Torque VS Horsepower... 100ftlbs TQ gain on a N/A J-Swap?

Patricio said:

Billy you can check and search any oem dyno sheets show the factory ecu cut's fuel off at 7800rpm unless it chipped.
there's at least 10 dynos just on the first page here on a thread you started that cut off at 7800, which is the same my car does on my tests.
http://www.nsxprime.com/forum/showthread.php/109312-NSX-Dyno-Library-Registry

some chips increase the rpm to 8300.
As you know the rpm tach is always off, its shows it cutting off higher than actuality..

Click to expand...

Out of the 9 cars on the first page, 4 of them went to ~7,800rpm and 5 went to 8,000. On page 2, Honcho and all of Jon K's dyno tests show 8,000 with factory ECUs and I don't know for certain if my car was chipped or not by the previous owner but it went to 8,300rpm. In my link on page 2, there are various dynos from the early 00s that went to 8,000rpm.

I agree the stock tach isn't accurate and its possible people lift at what they see is 8,000rpm on the tach (which may be ~7,800rom) instead of waiting for the rev limit or fuel cut at 8k or above.

Can you post your dyno and do you hit the rev limit before lifting?


Some people say the J does not sound as good or the same as a C. I have not heard them so I can't comment.

You haven't listed a few cons for the J:
-SOHC
-Long rockers in the valvetrain vs. The more direct DOHC action of the C engine (better for high rpm)
-I think ALL Js have VTEC only on the Intake while the C has intake & Exhaust.

stuntman said:

Some people say the J does not sound as good or the same as a C. I have not heard them so I can't comment.

-I think ALL Js have VTEC only on the Intake while the C has intake & Exhaust.

Click to expand...

I can't comment on the latest J series engines; but, the J series is my Pilot makes a churn above 3000 RPM that suggests that it is not happy operating there. The NSX mechanical noise is rather seamless as the RPM increases and enjoyable.


The latest Y4 and Y5 variants of the J35 have VTEC on both the intake and exhaust valves along with direct injection, the latter item probably facilitating the 11.5:1 compression ratio. The Y4 variant makes a claimed 310 hp @ 6500 RPM. Some of the J37 variants also have VTEC on the intake and exhaust valves.

Good catch, however the Direct Injected Y4&5 are probably not going to be used in many swaps. With a 6,800rpm factory redline, the valvetrain of the dual VTEC J motors looks to be very cumbersome and I question the longevity and integrity of all that mass for sustained high RPM.

stuntman said:

Good catch, however the Direct Injected Y4&5 are probably not going to be used in many swaps. With a 6,800rpm factory redline, the valvetrain of the dual VTEC J motors looks to be very cumbersome and I question the longevity and integrity of all that mass for sustained high RPM.

Click to expand...

I can't comment on the operation of the Y4 and Y5 valve train at elevated RPM, other than to note that it probably would not be the preferred choice if you were seeking the high RPM path to more horsepower. Based upon the commotion coming from the J in my Pilot, I would not be inclined to explore high RPM operation.

However, as an observation, a stock NA2 NSX will not pull red line or even make its horsepower peak (7500 RPM) in 6th gear. The J Y4 variant only puts out marginally more horsepower; but, it does it at 6500 RPM. I have not done the gear ratio numbers and estimates of power required versus speed; but, a stock j Y4 might net you a slightly higher top speed than a stock C32B, if that were your thing. The J Y4 variant puts out significantly more peak torque than the C32B (272 ft lb @ 4500 RPM versus 224 ft lb @ 4500 RPM) and I think that it is probably a safe bet that up to the horsepower peak on the J Y4 at 6500 RPM, it probably maintains that torque margin relative to the C32B. That higher torque output might make for a significant improvement in acceleration times. This would in part depend on whether the time lost by having to shift at a lower engine RPM (relative to the C32B) was offset by the increased torque output.

All of the preceding numbers are manufacturers claims at the crankshaft. Take them with the appropriate amount of salt; however, they are useful for comparison purposes.

At present, this is highly speculative as the Y4 variant only came out in 2014 and as such there are probably not a pile of them sitting in salvage yards waiting to be snatched up at bargain prices. The Y4's use of direct injection also complicates matters. I don't know whether Honda is using a mid pressure (I would guess so) or very high pressure fuel systems; but, DI fuel systems are probably less tolerant of 'back-yard' retrofits. That said, in 6 or 7 years, something like the Y4 variant could provide a reasonable transplant candidate for someone who needs a new engine, wants to stay close to OEM engine status and can't or doesn't want to put up the $ for a C30 / C32 rebuild. The flip side is that if you believe that the NSX is moving into collector car status, a J or and non C30 / c32 engine would seriously devalue it (as a collector car).

I'm not doubting the potential for increased NA hp/tq, however, there are a very limited number of J36 engines out there and no credible dyno graphs. All the numbers on the web are verbal. And even then, the numbers are not that impressive.

With that said, the cost for a J36 build is ~$5k and the retrofit kit (currently still incomplete) is another $2k. Putting in at least $7k and not having guaranteed results is going to be a tough call when compared to FI. I'm not knocking your J36 idea, in fact, I would do it too if there were credible results.

dablackgoku1234 said:

I'm not doubting the potential for increased NA hp/tq, however, there are a very limited number of J36 engines out there and no credible dyno graphs. All the numbers on the web are verbal. And even then, the numbers are not that impressive.

With that said, the cost for a J36 build is ~$5k and the retrofit kit (currently still incomplete) is another $2k. Putting in at least $7k and not having guaranteed results is going to be a tough call when compared to FI. I'm not knocking your J36 idea, in fact, I would do it too if there were credible results.

Click to expand...

i agree the information is limited but there are a few dyno's out there in the 280-290whp 260-270wtq plus jeff evans 440whp extreme build is undeniable thus showing that power can be extracted above the capabilities of any known N/A C30/32, obviously that 440whp drag motor would not apply to a road-going NSX but the capability and proof is there thus making it far from impossible to expect 300 to 340whp.... that car runs 9's..... no NSX has run 9's yet not even with 700whp. and of cousre i undersantd the nsx is not a drag machine, but that drag car is good example making it hard to deny that car has some serious power or claim the dyno is false..

but the cost is not 7k as you mention above because you will have your OEM C30/32 engine to sell for $5k-ish therefore the NET cost to you will be $2k in that scenario which is equal to the cost of new NSX headers installed for a result of 250whp / 190wtq

I'm not claiming any of this to be fact either, I created this post title with "?" mark because it is a quest for information, hopefully more people will research and maybe someone with more knowledge will come and help confirm what can be expected from the j series at different build levels.

Great thread....and all this time I thought the difference was HP=How fast you hit the wall & Torq=How far you move the wall after you hit it.
Seriously, great info here.

Coz said:

Great thread....and all this time I thought the difference was HP=How fast you hit the wall & Torq=How far you move the wall after you hit it.
Seriously, great info here.

Click to expand...

thanks,



------------------------------------------------

UPDATE:

I've called an met with various builders and owners of a few of the fastest all motor J engines i could find
And just figured to share the info i have found over past few months:
Conclusion the engines can make 325-400whp+ / 300-325+wtq and can spin 8000-8300 RPM on proper builds.
All this information was with the intention to make a road driven built engines to last years. (not drag racing)

Interpret the information as you wish


Sources:
power to rev racing: sean in FL
http://www.powerrevracing.com/
Largest manufacture of bolt-ons for the J series and one of first people to start swapping J series , and avid road racer shop car for fun. His personal preference is to use the very basic OEM parts build w/ 305whp and 275wtq stock J32a2, and pistons from j32a3 12:1 and bolt-ons. (yes that's 65-75lbs of tq and 30-40whp more than an NSX engine with all the bolt ons)
out of coincidence a local shop I am familiar with just a few minutes from my house that works on allot of ferrari challange race cars Force fed motorsports they are also the builders of most of the nobles in this country and their credentials are vast. Happens to be next door to where power to rev started out and fully they confirmed the success that power to rev has had with the setup they also have made excellent manifolds for the J .

inlinepro engines: in VA
https://www.inlinepro.com/s1/c-23-engine-builds.aspx
Built Jeff Evans 440whp N/A drag engine that the dyno is posted above here, car runs around low 10's (engine specs are included in inline pros email below)

evans tuning: Jeff evans in NJ
http://www.evans-tuning.com/
Well respected tuner shop in NJ owns/built/races a few 10 second cars, J engine as specified above engine built by inlinepro.

TB motorworx: San diego
http://tbmotorworx.com/
Owns races builds race motors, their J3.9 puts out N/A 500whp and runs consistent 9's
Fabricates the custom manifolds and/or will provide to a customer all the proper diameters and information necessary for proper manifold flow for an outside company to fabricate the manifolds using his formula.

to start some Info for the less less experienced: It very important when talking abut the J series to understand that they make ALLOT more Torque than the NSX' engine does.... so the WHP gain may appear low but TQ gain compared to our C30/32 is huge. they easily make Turbo level torque, when turbo guys talk about the huge benefits of 300lbs torque they get, the J can have close the same thing. The power band power compared to a 8psi C series will be just as strong and more predictable up until 5250RPM, after wards the turbo may climb to 400whp for the last 2000rpm and the built J series will only climb to 350-320 or 300 depending on the choices made during build. The difference is basically there will be no more waiting around for the engine to rev to 7000 to feel the acceleration, the acceleration will be as soon as you hit the gas everywhere in the power band. kind ok like electric cars get praised for having instantaneous pull.
Overall it will drive very similar to a CTSC but N/A, plus the J series provides a 61-70lbs weight reduction even more so when compared to CTSC 70-80 lbs weight addition that is a net difference of around 150 lbs over the rear axle of an already rear heavy car.


First the basics of why some forum dynos are low (amateur home builds):

Part 1
According to all the builders, the exhaust manifolds are a Crucial limitation of at least 30-40hp on even the most basic and OEM setup and there is currently no remotely acceptable aftermarket exhaust manifolds available. Therefore required for any engine, and the lower dynos found do not have proper manifolds.
The comparison and understanding is simple for us NSX guys to understand since even in an exotic as the NSX engineers still left 20+ hp in the header alone so you can imagine on the J series which is an even larger engine with even less header development and more restriction since they did not want to blow out automatic transmissions (this is also evidenced by honda including only single exhaust port on some of the jseries) they actually intentionally restricted the header.

Part 2
Compression,
The J series starts making allot more power around 11:1 and up preferably 12:1+
the easy answer to this is to use the J23a3 piston inside the J23a2 head, it bumps the compression to +/- 12

Part 3
there are some misc adapters and ect that power to rev racing makes, very inexpensive stuff $300-$400
and Manifold porting Porting

With Part 1, 2 & 3 taken care of plus a few other bolt-ons the choices using OEM Honda parts, the consensus is:
All of these include Custom exhaust Manifolds $1200-1500, Ported intake manifold $400-500, misc 300-500, and tune
J32a2 engine, w/ j32a3 pistons = 12ish compression will make 300whp 275wtq / RPM limt 7200
J32a2 engine, w/ j32a3 pistons = 12ish compression & J35 crank/rods = 300whp/300wtq / RPM limit 7000
J32a2 engine, w/ j32a3 pistons = 12ish compression & J37 crank/rods = 320whp 300wtq /RPM limit 6800
any of these options can be put together for around $3000 plus $2500 for bolt-ons & ect as mentioned above

With upgraded springs and retainers the RPM limits can be increased an additional 200 RPM conservatively.

That's the basic options, and results compared to a full bolt-ons NSX can get 50-60whp more and around 65 to 100 lbs of TQ MORE that is a massive difference in acceleration. sure you shift sooner but it does not matter because you don't have to force the car into max RPM..... it will pull immediate at almost any RPM...... since the Torque curve will be as flat as the earth was once believed to be...

I'm just sharing what I've found so far, from reputable builders that actually have produced real racing results.
please take it with a grain of salt as i have not built any of these myself..

Now on with the bigger builds and increased RPM limits, still for road, street ect, (not crazy drag limits)

Part 3
The third most important part is the cams, the stock cams are not designed for performance at all, similar to the NSX again but twice as much power left in the cams since these were made for economy cars.
Proper Billet Cams will bump any of those ratings up another 10-20hp
costs 1-2k

Part 4
Engine head flow Like any other car heads this can make huge difference
costs 2k-3k

With all the previous mods, plus heads those numbers will start climbing to 340whp+/ 320+wtq and RPM will support 8000-8300 RPM + $7,000
When adding built bottom ends with custom cranks, rods, bores, pistons ect power will be 350-400whp and 350+ wtq


They all spoke allot about how vastly Honda has developed the Race engine J series and still continues to do so and that the J series race engines are using a variety of OEM available parts, he claims almost all the parts Honda uses in the race engines are scatted along the model lineup somewhere, its up to you to find and choose those parts as needed. thus why some blocks are so much stronger than usual and hold crazy turbo power and some cranks and rods are forged from the factory and some pistons are more durable than others ect.





so now i will just forward you guys some of the emails and communication I've organised:

-----------------------------------------------------------------------------------------------

This is with POWER rev racing not allot on email since i have speaking on phone mostley.

Hi,

To get toe 300 WHP, you don't need a built motor. You just need the proper bolts ons and AEM tune.

https://www.youtube.com/watch?<wbr>v=VAxZv-nbdsM
(Bolt Ons list is listed in the video notes)

If you're looking to make more HP than this, then we have something at the moment that we might consider selling.

We just finished building a 3.5 block though its not assembled yet. Its being setup to make around 380 Hp with proper heads.
12.5 Compression Custom CP Pistons (Internal Milling, Special X Forging, Gas Reliefs, Coated Tops, WPC Treated Rings, WPC Treated Wrist Pins)
Cyro Treated OEM Rods, Custom ARP Rod Bolts, Shoot peened, and polished rods for final look
WPC Treated Crankshaft
WPC Treated Bearings
Block Line Bored
Bored .5mm over.
Whole assembly balanced together.

If we were to sell this block it would have to be for $4,600.

That would cover the cost we have in this block. Though this is supposed to be for our car. So it's not really up for sale, but we would be willing to sell it as I don't see us putting it in the car within the next year.

If you're really interested I could send you more pictures tomorrow when the sun is out.Hi,

------------------------------------------------------------------

basic email from Jeff Evans whom later refered me directly to inlinepro which is the next longer deatiled information

Jeff evans

Tiago,

A J36 would be the way to go. You could retain the OEM cams/valvetrain, but increase the static compression to around 11:1 on the J36 and will be in your 325-350 power range. The red line would be around 7,000 rpm maximum to keep it reliable for track events. Would you be interested in doing the entire long block, short block and would you need the core engine sourced?


Thanks!



Jeff Evans

Evans Tuning

www.evans-tuning.com

1.866.975.TUNE



This was conversation with INLINEPRO

Hello
I'm intrested in a turn key built J series engine to swap into an nsx
im open to your reccomendations, and looking for something 325-375whp N/A for HPDE and street usage if possible and have other NSX owners looking as well since as of a few months ago an engine swap kit has been made available and quite a few nsx owners are jumping on the band wagon
I started a thread seeking the capabilities of the J swap for the NSX and I’m sure others would be interested in finding a shop with J experience that could reliably provide built engines to drop in.
Some people are doing twin turbo 450+ j builds as well.
http://www.nsxprime.com/forum/showt...S-Horsepower-100ftlbs-TQ-gain-on-a-N-A-J-Swap

ANSWER: <[email protected]>Yes, we can do that for you. The hp will depend on your budget as we have many different build levels. Below are a list of pricing and build options available. For 325-335whp you could do the stage1 shortblock, stage1 cylinder head, and stage2 or stage3 Regrind. If you are looking at 350-400whp you would have to go up in stages. BTW: Jeff's 440whp build is a stage 2 shortblock with 14.5:1 compression, Stage3 Cylinder heads, and Stage3 Regrinds. His set up is streetable if you run lower compression 12-13:1

QUESTION: what would be a rough estimate of a turn key engine fully assembled and ready to drop in for the two examples you mentioned?
"For 325-335whp you could do the stage1 shortblock, stage1 cylinder head, and stage2 or stage3 Regrind. If you are looking at 350-400whp you would have to go up in stages.
Btw Jeff's build is a stage 2 shortblock with 14.5:1 compression, Stage3 Cylinder heads, and Stage3 Regrinds. His set up is streetable if you run lower compression 12-13:1"

ANSWER: $6600 for the 325-335whp. For the higher whp you would be looking at $9500. You would also need the core block which ranges from $500-$700.

QUESTION: and what are your thoughts on the upper RPM limits and performance on these setups since a few of us are worried about losing 500-1000 RPM compared to the 8000-8300RPM limit most of us run on the stock NSX motor.

ANSWER:On the stage1 shortblocks we would recommend around the stock J rev limit. If you build the stage2 block 8000-8300 would be fine for daily driving.

QUESTION: how long do your builds take?
ANSWER:Turn around time is 4-6 weeks for the builds

<[email protected]>
J-series build Options:

Stage1 Shortblock $2495 J32/J35/J37 Using existing Crankshaft (Recommended for All motor)
Includes: 89-89.5mm Cast High Compression piston set, Bearings, Gasket kit, Hot tank, Machining, Balance rotating assembly, Blueprint, and Assembly
Stage1 Shortblock $2495 J32/J35/J37 Upgrading the Crankshaft(Add $700-$1000 for OEM Parts) (Recommended for All motor)
Includes: 89-89.5mm Cast High Compression piston set, Bearings, Gasket kit, Hot tank, Machining, Balance rotating assembly, Blueprint, and Assembly

Stage2 Shortblock $3995 J32/J35/J37 Using existing Crankshaft
Includes: 89-89.5mm Forged High/Low Compression piston set, inlinePRO Connecting Rods, Bearings, Gasket kit, Hot tank, Machining, Balance rotating assembly, Blueprint, and Assembly
Stage2 Shortblock $3995 J32/J35/J37 Upgrading the Crankshaft(Add $500)
Includes: 89-89.5mm Forged High/Low Compression piston set, inlinePRO Connecting Rods, Bearings, Gasket kit, Hot tank, Machining, Balance rotating assembly, Blueprint, and Assembly

Stage3 Shortblock $6495 J32/J35/J37 Using existing Crankshaft
Includes: inlinePRO Ductile Iron Closed Deck Sleeves, 89-93mm Forged High/Low Compression piston set, inlinePRO Connecting Rods, Bearings, Gasket kit, Hot tank, Machining, Balance rotating assembly, Blueprint, and Assembly
Stage3 Shortblock $6495 J32/J35/J37 Upgrading the Crankshaft(Add $500)
Includes: inlinePRO Ductile Iron Closed Deck Sleeves, 89-93mm Forged High/Low Compression piston set, inlinePRO Connecting Rods, Bearings, Gasket kit, Hot tank, Machining, Balance rotating assembly, Blueprint, and Assembly

Stage 0 Cylinder Heads $1495 J32/J35/J37
Includes: inspect, disassemble, hot tank, soda blast, performance valve job, grind valves, guide seals, resurface deck, blueprint, and assembly.

Stage 1 Cylinder Heads $2125 J32/J35/J37
Includes: inspect, disassemble, hot tank, soda blast, performance valve job, grind valves, guide seals, resurface deck, blueprint, inlinePRO valvesprings/titanium retainers, and assembly.

Stage 3 Cylinder Heads $3495 J32/J35/J37
Includes: inspect, disassemble, hot tank, soda blast, Bronze Intake/Exhaust Guides, Port & Polish, performance valve job, grind valves, guide seals, resurface deck, blueprint, inlinePRO valvesprings/titanium retainers, and assembly.


Additional:
Longblock Assembly $750
Oring $375
Check Valve to valve and Valve to Piston $500
Stage 1,2,3,4,5,6 Billet Camshafts $1995
Stage1,2,3 Reground Factory Cams $995 (Core Fee)
36mm, 36.5mm, 37mm 21-4N Intake Valves $17.95 Each
30mm 21-4N Exhaust Valves $17.95 Each
30mm Inconel Exhaust Valves $27.95 Each
37mm Titanium Intake Valves $37.95 Each
30mm Titanium Exhaust Valves $37.95 Each
ITB Set (Call for Sizing) $6495
$549 Single Spring 75lbs Install/180lbs @.400" Lift/Coil bind .520"
$649 Single Beehive Spring 100lbs Install/[email protected]" Lift/Coil Bind .605"
$649 Dual Spring 80lbs Install/210lbs @ .400"/Coil Bind .570" (Requires Custom Bronze Guides $8 each)
Bronze Guides $8 Each
Main Stud Kit $175
Head Stud Kit $295




</[email protected]></[email protected]>

I thought the best reason to use a J was the built to to turbo charge and make a lot of power and have a relatively cheap motor to replace if it goes BOOM.

If that's your thing, sure.
Or for $10k (including the core engine cost) you can have all motor 350-375whp 325wtq and weigh 150lbs less in the rear than the OEM C including all the 75ish lbs of turbo parts/pipes/inter-coolers/fluid/hangers hanging back behind the axle.

and hopefully a little less overheating, plumbing, and heat in general,
the usual benefits of N/A, without getting into a Turbo vs N/A debate

I am trying to make a final decision to turbo or stay N/A
I have the whole turbo system ready to install and the AEM infinity already installed, and now having last minute thoughts.

If you were a joe schmo guy who putts around on a track day, it wouldn't really matter what you do. But for as fast as you are, and since you live in a hot FL, you should be prepared to spend ALOT of money on the cooling system of your car with high end intercoolers, radiators, oil coolers, etc... To keep the heat in check. All of that is weight and if you cheap out, you'll have to spend the money again (more) to do it right to keep cooling under control, or give up and be in a deeper financial hole when you're frustrated that all the random parts you bolted on do not work as efficiently and effectively as you hoped for.


- Edit -

Source of the OP's dynochart picture of a $10K+ built J35A8 (2005-2008 Acura RL &2007-2008 Acura TL Type-S) 3.5L with 12.0:1 compression ratio and ~ 11.56mm intake & 11.18mm exhaust lift (compared to the NSX's 10.2mm & 9.0mm) -which made 317whp/265wtq

http://acurazine.com/forums/perform...112/j35-12-1-heads-cam-build-complete-897606/




I'm still yet to see a 325whp+ dyno that wasn't a 13-14:1 compression ratio race motor.

The build above is an amateur build.. with the wrong J35a8 heads and without headers and crap cams.. his j35a8 heads have one single exhaust port on each head instead of 3 ports on each head. and he used various shops to complete, none with J experience since he was telling the shops what to do. "ended up costing roughly $4k just in labor. I probably chewed through $6k on the cams alone" and "there is at least 15-20whp left in the cams" and "skipped bismoto cams and went straight to the source" and "heads were milled, and we hit a limit of 40 thou on j35a8 heads" are a MASSIVE restriction, Huge mistake. and he milled the heads instead of using the right cams.

But even then, that dyno shows 317whp and 265wtq, (more wtq than a CTSC makes) so add headers with the right heads +20-40 whp plus add the right cams 10-20whp on and the goal of 350whp / 280wtq is very real. consider the 70lbs weight reduction from lighter engine. and its a winner

I already posted dyno of Evans engine pushes 440whp on stock block. Just reduce the compression form 14:1 to 12:1... everything else is oem parts build except rods and pistons (because 14:1 compression) the 3.65L total using J32 head, J37 crank, stock block, stock valves, cam is a regrind. it does have head work. De-tuned at 12:1 it will make 350whp. that torque curve is nuts! still making power at 8000RPM on a stroker is unheard of.

Any way... some analysis of piston speeds...

Its clear with honda's new philosophy is designs with longer strokes and thus also the J is inherently designed for higher piston speeds than a C for two main reasons that honda mentions frequently.. the 60 degree engine is much more inherently balanced than our 90 degree C, and second the SOHC is allot less moving parts. Honda is using smaller bores across their whole lineup and have chosen to stay at a 89mm bore even after experimenting with larger bores 93mm in C32's... these same components are even designed by oem to operate at J37's 96mm massive stroke...

J37 96mm @ 6800rpm 21.7 mps
J35 93mm @ 6800rpm 21.1 mps
J35 93mm @ 8000rpm 24.8 mps = 14% increase over stock
Evans J36 96mm [MENTION=4141]8000RPM[/MENTION] 25.6mps = 18% over stock

C30 78mm @ 8300rpm 21.5mps
SOS 3.6 88mm @ 8300rpm 24.3 mps = 13% increase over oem
TODA 3.5L 84mm @ 9000rpm 25.2 mps = 17% increase over oem

k24 99mm @ 7000rpm 23mps
K24 99mm @ 8000rpm 26.4mps = 15% increase over oem
K24 99mm @ 9000rpm 29.7mps = 29% increase over oem

Others for reference:
B16 77mm @ 9000rpm 23.1mps
F20 84mm @ 9000rpm 25.2mps
K20 86mm @ 9000rpm 25.8mps


It's clear newer hondas are being designed with higher piston speed capabilities.

Patricio said:

The build above is an amateur build.. with the wrong J35a8 heads and without headers and crap cams.. his j35a8 heads have one single exhaust port on each head instead of 3 ports on each head. and he used various shops to complete, none with J experience since he was telling the shops what to do. "ended up costing roughly $4k just in labor. I probably chewed through $6k on the cams alone" and "there is at least 15-20whp left in the cams" and "skipped bismoto cams and went straight to the source" and "heads were milled, and we hit a limit of 40 thou on j35a8 heads" are a MASSIVE restriction, Huge mistake. and he milled the heads instead of using the right cams.

But even then, that dyno shows 317whp and 265wtq, (more wtq than a CTSC makes) so add headers with the right heads +20-40 whp plus add the right cams 10-20whp on and the goal of 350whp / 280wtq is very real. consider the 70lbs weight reduction from lighter engine. and its a winner.

Click to expand...

Your knocking on the door of 300whp with just an intake and headers. Notice how the torque tanks and HP max is at 6,800rpm? It is not going to spin to 8K without better cams and more head work.

HP is a function of torque at a given RPM. Your motor is making close to 300whp at a higher RPM with less torque down low. A Camaro will make more torque off idle than a CTSC or J motor, but could make less peak power and less power up top. It all depends on what you're trying to do.

Patricio said:

I already posted dyno of Evans engine pushes 440whp on stock block. Just reduce the compression form 14:1 to 12:1... everything else is oem parts build except rods and pistons (because 14:1 compression) the 3.65L total using J32 head, J37 crank, stock block, stock valves, cam is a regrind. it does have head work. De-tuned at 12:1 it will make 350whp. that torque curve is nuts! still making power at 8000RPM on a stroker is unheard of.

Click to expand...

Conjecture. You don't know what the power will be at a given compression ratio until it's tested. You need to do headwork & cams to make power to 8K, and even then the piston speeds are very high and it'll be interesting to see how long the motor lasts outside of drag racing.

Patricio said:

Any way... some analysis of piston speeds...

Its clear with honda's new philosophy is designs with longer strokes and thus also the J is inherently designed for higher piston speeds than a C for two main reasons that honda mentions frequently.. the 60 degree engine is much more inherently balanced than our 90 degree C, and second the SOHC is allot less moving parts. Honda is using smaller bores across their whole lineup and have chosen to stay at a 89mm bore even after experimenting with larger bores 93mm in C32's... these same components are even designed by oem to operate at J37's 96mm massive stroke...

Click to expand...

Higher piston speeds aren't good. The 60 degree V6 is not that much more balanced than a 90 degree V6 when both have split pin cranks. The 60 degree is more compact (cube), and makes packaging much easier across a broad line of vehicles with smaller (but taller) engine bays. The smaller bore spacing, corresponding smaller bores, shorter rods, and smaller crank help shrink the size of the J-series motor which is important when mounted transversely in an engine bay -which most of the Js are.

The NSX was designed from scratch so fitting a small engine bay wasn't a determining factor. Honda was racing 80 degree turbo V6s in F1 years before their first production V6 (C20A) including a turbocharged variant. The lower center of gravity of the 90 degree was better for performance and handling than a taller, more compact 60 degree engine so the advantages of the 90 degree must have outweighed the disadvantages. It was also mounted longitudinally in the Legend, which had a low hood line.

With ever stringent crash standards, amortization of R&D and production of spreading an engine across multiple platforms, and need for more torque to move heavier and heavier cars, it makes sense to move away from a lower, high revving 90-degree V6 to a smaller, more compact, torquier 60 degree V6.

Patricio said:

J37 96mm @ 6800rpm 21.7 mps
J35 93mm @ 6800rpm 21.1 mps
J35 93mm @ 8000rpm 24.8 mps = 14% increase over stock
Evans J36 96mm [MENTION=4141]8000RPM[/MENTION] 25.6mps = 18% over stock

C30 78mm @ 8300rpm 21.5mps
SOS 3.6 88mm @ 8300rpm 24.3 mps = 13% increase over oem
TODA 3.5L 84mm @ 9000rpm 25.2 mps = 17% increase over oem

k24 99mm @ 7000rpm 23mps
K24 99mm @ 8000rpm 26.4mps = 15% increase over oem
K24 99mm @ 9000rpm 29.7mps = 29% increase over oem

Others for reference:
B16 77mm @ 9000rpm 23.1mps
F20 84mm @ 9000rpm 25.2mps
K20 86mm @ 9000rpm 25.8mps
C30 78mm @ 9500rpm 24.7mps

It's clear newer hondas are being designed with higher piston speed capabilities.

Click to expand...

-I don't recall SOS running a stroked C motor to 8,300rpm. I think they recommend a few hundred RPM less than 8K.
-Link to info on the Toda stroker?
-K24s rarely exceed 8K rpm, let alone 9K. Maybe they survive at 9K in drag racing but they're not many people doing it. Most consider 7,600-7,800 the limit.

You don't really want high piston speeds and 24mps is pretty high for any motor. Bad things start happening. But the J is cheap so try it and document the durability!

cptnsx said:

......Hell even the 458 Italia's claim is BS since pretty much every CUSTOMER dyno I've seen of the car only dynos around 320rwtq AT 4.5 liters. Hell the old 5.7 GM motors would only dyno around 300rwtq and the 4.6 Mustang GT was around 320rwtq.

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Wow. U made my day since I'm making around the same RWTQ.

Patricio said:

The build above is an amateur build.. with the wrong J35a8 heads and without headers and crap cams.. his j35a8 heads have one single exhaust port on each head instead of 3 ports on each head. and he used various shops to complete, none with J experience since he was telling the shops what to do. "ended up costing roughly $4k just in labor. I probably chewed through $6k on the cams alone" and "there is at least 15-20whp left in the cams" and "skipped bismoto cams and went straight to the source" and "heads were milled, and we hit a limit of 40 thou on j35a8 heads" are a MASSIVE restriction, Huge mistake. and he milled the heads instead of using the right cams.

But even then, that dyno shows 317whp and 265wtq, (more wtq than a CTSC makes) so add headers with the right heads +20-40 whp plus add the right cams 10-20whp on and the goal of 350whp / 280wtq is very real. consider the 70lbs weight reduction from lighter engine. and its a winner

I already posted dyno of Evans engine pushes 440whp on stock block. Just reduce the compression form 14:1 to 12:1... everything else is oem parts build except rods and pistons (because 14:1 compression) the 3.65L total using J32 head, J37 crank, stock block, stock valves, cam is a regrind. it does have head work. De-tuned at 12:1 it will make 350whp. that torque curve is nuts! still making power at 8000RPM on a stroker is unheard of.

Any way... some analysis of piston speeds...

Its clear with honda's new philosophy is designs with longer strokes and thus also the J is inherently designed for higher piston speeds than a C for two main reasons that honda mentions frequently.. the 60 degree engine is much more inherently balanced than our 90 degree C, and second the SOHC is allot less moving parts. Honda is using smaller bores across their whole lineup and have chosen to stay at a 89mm bore even after experimenting with larger bores 93mm in C32's... these same components are even designed by oem to operate at J37's 96mm massive stroke...

J37 96mm @ 6800rpm 21.7 mps
J35 93mm @ 6800rpm 21.1 mps
J35 93mm @ 8000rpm 24.8 mps = 14% increase over stock
Evans J36 96mm @8000RPM 25.6mps = 18% over stock

C30 78mm @ 8300rpm 21.5mps
SOS 3.6 88mm @ 8300rpm 24.3 mps = 13% increase over oem
TODA 3.5L 84mm @ 9000rpm 25.2 mps = 17% increase over oem

k24 99mm @ 7000rpm 23mps
K24 99mm @ 8000rpm 26.4mps = 15% increase over oem
K24 99mm @ 9000rpm 29.7mps = 29% increase over oem

Others for reference:
B16 77mm @ 9000rpm 23.1mps
F20 84mm @ 9000rpm 25.2mps
K20 86mm @ 9000rpm 25.8mps


It's clear newer hondas are being designed with higher piston speed capabilities.

Click to expand...

Please see the bottom of the thread, wrong car but right motor http://www.nsxprime.com/forum/showthread.php/175785-Cylinder-Head-Flow-Tested/page2

Mario92NSX said:

Please see the bottom of the thread, wrong car but right motor http://www.nsxprime.com/forum/showthread.php/175785-Cylinder-Head-Flow-Tested/page2

Click to expand...

I dont know what you meant by that statement? are you referring to the s2000 that puts down 450 at the engine/crank which equals 391whp?

NSX Stroker with ITB's is $20K for 390whp and a 4-6month build time and that does not include cost of the $6-$8k engine itself for a total cost of 25K+.
This thread is about getting nearly the same performance out of J35 for under 10K including the motor and with less than 1 month build time.


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Back to subject some new OEM specs to compare

these engines have the same exact Stroke and RPM limits we are seeking out of a built head J35 in an NSX

2006 Audi RS4 V8 8250rpm limit 93mm stroke = 25.2mps
2015 Mustang GT350 V8 8250rpm limit 93mm stroke = 25.2mps

the J35 is the same stroke and thus same 25.2mps at 8250rpm and only 24.8mps at 8000rpm

FWIW: Scott adams this past weekend ran a full track day with multiple 40 minutes sessions in his J swapped NSX. With 100% stock J35a3 motor with a 7500RPM limit with no issues. nothing was upgraded in that motor.

Bumping a semi-dead thread here... Have you checked out Velocitized work on the J-swap?

http://www.nsxprime.com/forum/showthread.php/189108-J-Swap-Motor-Mount-Adapter-Kit