Whats the most HP/TQ the Stock bottom end can handle? 3.0 and 3.2

[Dv8tion388]

I've searched around but can't find a satisfactory answer. At what point does the bottom end start needing stronger internals? N/A, F/I, Blown, Nitrous, 350,400,450? Factor in TQ as well please.

Any feedback would be great.


Thanks,

~Dv8

 

[Vega$ NSX]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

Actually it's been discussed several times in several different threads, but part of the problem is that it is a difficult question to answer. That is because there is no definitive answer that will be 100% safe.

Each NSX engine is built differently. Not to mention they will all have varying amounts of wear and tear and each turbo/SC system will be different too. Too many variables = uncertainty.

Having said that, one common answer and in my experience, 380-400 whp is about the limit of which a stock engine can handle reliably. However, that is no guarantee. Some people are pushing more than that and haven't had any problems. On the other hand, when I pushed 395 whp, I lifted my head gasket and when I hit 415 whp, I crushed a piston head. On one hand my engine had 142,000 miles on it, but on the other hand, a compression leak test came up very good (which is why we didn't go with the rebuild in the first place).

My advice: If you want to go FI, stay under 380 whp with a comptech SC or a turbo at no more than 8lbs of boost. Otherwise, just rebuild the engine and boost away. It will save you a ton of money, time and headaches in the long run.

 

[nsxotic911]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

I'll chime in here with my peice of data...
I have a CT Whipple HighBoost w/ AEM.
*About 390-400RWHP for the last 7,000+ miles.
*Reliability has been 'good. 'Good' for me means that, it hasn't blown up, I haven't felt the engine pre-detonate doesn't burn oil, and the compression check has been 200+ on all cylinders recently. Haven't done a leakdown, but will soon. Also want to get a oil analysis in the next couple of weeks.
*During 60/70F weather, I see max about .5 bar (7.5 PSI), but at night, I see more than that....

Nonetheless, I still do have general worry sometimes. I am scheduled to get it looked at and re-tuned with greater precession soon as I am putting the wideband in

With that said, more and more I am a believer that for the 'average Joe' the most hassle free and worry-free way is to keep it stock. Nonetheless, if you're not going to be happy with stock peformance (I wasn't, I know some people are, and some people are not), go boosted, it's absolutely amazing.

If one is smart and manages their risks well, the engine should last a very long time (and maybe longer), or so I hope

Engine wise, my understanding is that the 3.2 has slightly stronger engine characteristics, though with the added complexity of OBD-II

 

[Dv8tion388]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

I was just looking for a roundabout number, 400hp is what I keep seeing. Thank you. How about TQ? What would you say is the limit there on a healthy under 100k 3.2 engine.

Thanks again.

~Dv8

 

[AdvansCPAP]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

Stock internals weren't designed to handle 60-100% more power. From my experience, anything over 50% over stock HP/Tq on a factory NA motor is a ticking time bomb. 3.2's have stronger headgaskets than 3.0, but just consider that as a tiny bit of insurance. For a factory turbo'd motor (ie STI/ EVO), you can push them a hella lot more since they are built to handle boost.

Why you think that one of the reasons Comptech SC's are sold at the dealer? Not only because it's smog legal, but doesn't push the motor beyond safe limits. Look at all the big manufactures who produce reliable turbo/sc/NOS kits. They all basically put out the same power 30-50% increase over stock and boost the same 5-7 PSI. Why? Because they know it's safe and they do not need anyone bitching at them for blowing motors. Then you have the Mom and Pop kit builders. Sure they can build the kits, especially ones that put out impressive numbers for a good price too. Bonus huh? As always, people start blowing motors and all of the sudden no one talks about them anymore.

Look at what happened to Basch and Cybernation. I remember everyone was all excited when they were doing it and saying screw that weak Comptech SC. Now where are those kits? No one says anything about them anymore..hmmm. After that, everyone’s talking about the Comptech again and lusting after an AEM tune. Gruppe M and Bell kit always just lingered. Then comes SOS and Boostzilla kit. SOS never completed one. Boostzilla says you need a built engine after a certain PSI. Probably 6-7 pounds. Then Factor X and Lovefab jumps in..15G's just to get your feet wet? If your gonna spend that much money for a kit, you are a true dumbass for not forking out the 8+ g's to build the motor and do it right first time around. Oh, unless you just want to see how much you motor can take.:wink:

The best part is you will always hear about people bragging about how much they're putting out to the wheels or how much boost they're getting away with on a stock bottom end. Yah, yah, yah. The funny thing is, you rarely hear people saying they blew their motor and have to start all over, except -Vegas. How embarrassing and costly is that? Next thing you know, they're selling that "great" kit..lol. I'll take it, after I build my motor.:biggrin:

There's 3 guys on the forum running the new "gotta have" HP kit. All boosting 9.5-10+ PSI on a stock bottom end and putting out 400+ to the wheels. WOW!! Sure, everything is good for now and they're all happy. The one guy that has HP tune his car at the strip sounds like he pushing his engine and waiting for it to blow or something. By the way he talks, it seems like he's already prepared to rebuild it if it kabooms. Anyways, the question is if and when are they all going to pop?? How far can you go? We'll see with those Mom and Pop turbo/sc kit's running 400+ HP. Actually, any of the kits listed above are not to blame for a blown motor, but just a weak, non-built motor and bad tune is the problem.

I bet the majority would agree with no more then 50% above stock.
.

 

[Dv8tion388]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

I really appriciate all the advice. Ive lurked here from time to time reading various threads that have interested me. Hopefully you all wont be discouraged by the fact the Im the performance moderator of the Legend forums and that I dont actually own an NSX but have a Legend, for the past 8yrs. Although the two motros are very different they do have many things in common. I just posted 316WHP and 345WTQ On the stock RL bottomend and can push it further with bigger nitrous jetting. The NSX AEM EMS allowed me to take full advantage of the motor potential thus far.
Im considering a turbo setup now to make it all worthwhile, I have tons of nitrous experience, all the tools to make a custom kit happen, just want to know everything Im in for. Im not one to push, so 350-400 to the wheels out of a FWD car is fine with me. If I blow it being conservative then i'll wipe my brow and build it right.

If you all have more to add please do.
Thank you all again,

~Dv8

 

[JeffShoots]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

HP and TQ about 1k at the rear but for how LONG

 

[Semnos_NSX]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

Am I the only one with the mentality of “if it blows, that’s just an excuse to build the motor and crank up the boost”? Sure, no one wants their motor to blow, but if it happens, suck it up, build it, and have more fun than ever before! For the record, I have the CTSC high boost and dyno’d at 372. No problems so far (knock on wood)!

 

[CDX_NSX]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

Christian, my car was pushing about 400 rwhp for a number of years before a HG leak was detected. I do blame that on management, however. As for torque, I believe I was pushing about 289 lb-ft, but I'm sure that it will handle more.

As mentioned, 400 rwhp is "generally" what the motor can handle reliably, and 450 is really pushing it. Anything between that is almost luck of the draw as far as longevity of the stock motor is concerned. All this is certainly assuming a proper tune.

 

[JeffShoots]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

At what point does the bottom end start needing stronger internals?

Is the "bottom end" the crank and block? Or are we talking about a long block? W/ Rods, Pistons,....ect, STOCK

If it's a stock long block W/ stock pistons about ~400RWHP but the STOCK block and crank can be built for ~1k HP.

 

[brandonsan]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

Am I the only one with the mentality of “if it blows, that’s just an excuse to build the motor and crank up the boost”? Sure, no one wants their motor to blow, but if it happens, suck it up, build it, and have more fun than ever before! For the record, I have the CTSC high boost and dyno’d at 372. No problems so far (knock on wood)!

I'm with ya. I don't want to blow my engine because I would like to sell it once I drop my built engine in. I didn't build my engine right away because I only had 3500 miles on my car when I bought the Lovefab Turbo system. I thought it was stupid to put a built engine in the car anyway without making sure the turbo system itself was reliable and getting a chance to see if I even liked the new setup. I like to modify my car in stages anyway to keep it exciting.

 

[Flexer]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

I'm with ya. I don't want to blow my engine because I would like to sell it once I drop my built engine in. I didn't build my engine right away because I only had 3500 miles on my car when I bought the Lovefab Turbo system. I thought it was stupid to put a built engine in the car anyway without making sure the turbo system itself was reliable and getting a chance to see if I even liked the new setup. I like to modify my car in stages anyway to keep it exciting.

And to think you were going to sell it. :biggrin:

J. R.

 

[nsxman2001]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

I'm with ya. I don't want to blow my engine because I would like to sell it once I drop my built engine in. I didn't build my engine right away because I only had 3500 miles on my car when I bought the Lovefab Turbo system. I thought it was stupid to put a built engine in the car anyway without making sure the turbo system itself was reliable and getting a chance to see if I even liked the new setup. I like to modify my car in stages anyway to keep it exciting.

I'm just curious on why u would put all that money into your car then sell it? seems like a waste of time and money..just my opinion

 

[Hothonda]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

I'm just curious on why u would put all that money into your car then sell it? seems like a waste of time and money..just my opinion

He means the original engine not the car I believe.........

 

[Bob Kenney]

Re: Whats the most HP/TQ the Stock bottomend handle? 3.0 and 3.2

Is the "bottom end" the crank and block? Or are we talking about a long block? W/ Rods, Pistons,....ect, STOCK

If it's a stock long block W/ stock pistons about ~400RWHP but the STOCK block and crank can be built for ~1k HP.

May be we ought to define a built motor [bottom end] so we are all on the same page.

The stock pistons have to GO, they are cast and a potential weak point in the engine when pushing boost. This is also a good opportunity to adjust the compression ratio to a "more compatible level" for a boosted engine.

I believe most of the cars running higher boost have sleeved their blocks and some have dealt with the open deck design.

Rods usually can lead to lively discussion, some feel the stock rods are sufficient others see them as weak link. Rod replacement probably needs to be "considered" if one is taking boost beyond 15 PSI.

Replacing the oil pump gears with billet type should be considered; given what happens to the #4 connecting rod bearing if there is the slightest glitch in oil flow. An Accusump may also be considered prudent.

How about the heads? That could lead to some more interesting discussions.

 

[BD]

NA NSX with just bolt-on, I got 302 rwp. That's with Fujitsubo header, GT-One v.2 Titanium exhaust, test pipes, and Mugen AIS. It is a OBDII so I left the ECU comptetely stock.

Danny on the other hand, built his Turbo engine from ground up. He's got more than 1000 HP to the crank.

FI without internal mod such as CTSC can go up to 400rwp, +/- some depend on the year and blower.

Stock engine can handle up to about 450 rwp, and more than that, the piston is not strong enough to hold it.

 

[RacerX-21]

Like Vega$ NSX answered in the beginning, it depends on many variables.

I had a friend making 498 whp from a 3.0 that never had the valve covers off, but this was a show car that never saw use other then the dyno, and he understood that he was over the line and was prepared to buy a new engine if and when it let go.

I have also seen track cars with unopened and perfectly tuned 380 whp (3.0) and a 400 whp (3.2) crack ring lands in the pistons that were never designed to make that kind of power.

I have seen an experiment that took 700 chp on a stock 3.2 before the cylinder presumably let go.

I have seen a number of heavily tracked engines making 330 whp to 400 whp that had stretched main caps. This leads to poor oil pressure, then bearing failure, then…

I have never seen a rod failure, ever! With ARP bolts I have track engines making 700+.

I have only seen one crank break with 360 whp but I blame the circumstances around it, and not the crank. And this car likely had more track miles then any.

The pistons are the weak link, then the main caps, then the rod bolts (presumably), then the deck support. Then you have other weak areas like the oiling system and valve spring retainers.

If you drive the car on the street exclusively then I think 400 is a good number.

If you occasionally track the car but fatherly protect it then 380 is a good number, but protecting it doesn’t mean that your afraid to go over 120 mph and leave it in gear at 7700 rpm for the remaining half of the straightaway.

If you abuse your NSX but only occasionally then 350 is a good number.

If you abuse your car and work every month as a track instructor, then 300 might need to be your limit.

Now I’m not saying that you cant make more, way more, it just may be costly depending on the cards.

 

[clr1024]

I have never seen a rod failure, ever!

Check this link

http://www.nsxprime.com/forums/showpost.php?p=591079&postcount=13

Now you have:biggrin: KGP said he was pushing 500, I assume RWHP.

Bob Kenney in this thread noted a fracture after a teardown.

http://www.nsxprime.com/forums/showpost.php?p=591292&postcount=16

From this thread:

http://www.nsxprime.com/forums/showthread.php?p=591079#post591079

If I was tearing apart my motor, the cost to replace the rods seems pretty cheap compared to a rebuild, I would do it just for reassurance.

 

[Bob Kenney]

Check this link

Bob Kenney in this thread noted a fracture after a teardown.

http://www.nsxprime.com/forums/showpost.php?p=591292&postcount=16

The rod failure I found was in the #4 cap, it is fractured through the cap next to the boss for the bolt. This is a rod that spun a bearing, I suspect the rod cap failure was caused by the spun bearing and not the other way around given #4 is prone to bearing failure.

I have the highest respect for Rob [RacerX-21] and his level of experience far outstrips mine; I give the greatest weight to Rob's observations and advise. He has help me with that advise on other occasions and I have never found it to be flawed.

 

[RacerX-21]

Good info, thanks for the links.

After reading all the threads it didn’t seem conclusive that the cause of the 500 HP damage was rod related.
In fact I just got off the phone and it is confirmed inconclusive.
On the other hand Bob certainly has found a crack, and though the 500 case is inconclusive it's possibly a rod.
Fluke or a pattern that has not had any visibility in the NSX community?
I know some builders advise the purchase of their products, but is this opinion founded on failure experience, prediction or even profit? Possibly similar to the weak drive shaft predictions.
I went straight to using ARP bolts because of prior engine experience with different brands, if you ask me I will tell you that you need these bolts but it isn’t because I have seen the OE NSX bolts fail, it’s because I’m predicting.
I did not have the luxury of having an off the shelf rod when I started building NSX engines, so I listened to Realtime telling me that they are fine in the 600-700 whp range where I intended on being. I have never had a failure. Bobs experience is the first credible account I have seen where a rod is faulty. I don’t want to keep referencing Realtime but they should hold some credibility with winning professional World Challenge championships, and having million dollar budgets to minimize losses due to part failure.
They run OE rods (and drive shafts) in an engine making over 600 whp and it’s pushed harder then most will ever push. After improving many areas, their weak link was the cylinder walls.
As you said, “it’s cheap insurance” I’m not sure if aftermarket rods could be considered cheap unless it’s relative to all the NSX build cost.
How are all those aftermarket rod stroker engines holding out? Are they failing?
I only know of one who hard tracks his Comptech stroked car.

 

[Elite]

Check this link

http://www.nsxprime.com/forums/showpost.php?p=591079&postcount=13

Now you have:biggrin: KGP said he was pushing 500, I assume RWHP.


If I was tearing apart my motor, the cost to replace the rods seems pretty cheap compared to a rebuild, I would do it just for reassurance.

When KGP's motor let go, I spoke with him. I believe the rod was an innocent bystander which was taken for a ride because of a bearing issue. This is just my theory however, so take it as a grain of salt.

And after market TI rods are not cheap. Specially when stock rods can handle more power then 99% of the FI NSX's on the road will ever make.

 

[RacerX-21]

Three rods were broke in total, two of them were in the middle of the long neck with the pin and the big end intact. The crank was broke among other things like the block. The most fantastic thing is those two rods breaking in the middle. Two or three rods wouldn’t fail at the same time along with the crank and the block; something stopped that engine and broke the rest of the parts. I know obvious. So if one rod could break all these parts including two other rods, it’s equally plausible that a different part could have broken all the rods.

No answer, just thinking out loud.

Interesting story about some good local friends. The NSX owners run the largest DE school in the country and even before that they tracked this car more than most could because the family has two drivers so they run two run groups. Anyway, were going out to dinner one day and Mark is late (Not unusual). We get a call that he’s about a mile away with car troubles. I drive there where he explains a loud knock. I tell him to start the engine so I can determine if it’s catastrophic like a bearing or maybe something simple like the flywheel hitting the sheet metal cover. He fired it up and shut it down even before I need to tell him. Yes that was a loud knock, I told him it sounded like more then a bearing, and it sounded like the clutch was hitting the case maybe that’s a good thing?

After discovering that the crank was broken I took the engine apart. I found the two rear rods connected to one half and the four remaining rods connected to the other half. The incredible part of this long story is that this engine actually ran this way. Briefly or not this was amazing! I’m not talking a crack; this thing was two separate parts.

 

[Factor X Motorsports]

When KGP's motor let go, I spoke with him. I believe the rod was an innocent bystander which was taken for a ride because of a bearing issue. This is just my theory however, so take it as a grain of salt.

And after market TI rods are not cheap. Specially when stock rods can handle more power then 99% of the FI NSX's on the road will ever make.

Just to clarify, KGPs rod snapped in half, all exhaust valves were bent, and the bearings were perfect. We have experienced quite a bit more "parts" failures since we have been tracking the car extensively and for long periods of time. In most cases what most consider "hard" street driving many of these circumstances will not show up. Working with Rob has helped us address many of these other issues and has definitely given us an edge on the road course.

Aftermarket rods are definitely not cheap, but if you are already in there and have the budget along with knowledge that you are going to go more down the road they may be justified. We're just happy to be in the 1%:biggrin:

 

[Factor X Motorsports]

How are all those aftermarket rod stroker engines holding out? Are they failing?
I only know of one who hard tracks his Comptech stroked car.

We are also curious about how these are going to hold up to extended track abuse. Especially with the added boost and high rpms. We almost took the plunge but will leave it for someone else to find out this time

 

[clr1024]

Good info, thanks for the links.

After reading all the threads it didn’t seem conclusive that the cause of the 500 HP damage was rod related.

I didn't mean to imply that the failure was because of the rod, that could be a chicken or egg argument. I was just linking you to a picture of a failed rod.

As you said, “it’s cheap insurance” I’m not sure if aftermarket rods could be considered cheap unless it’s relative to all the NSX build cost.

You are correct, by cheap I mean relative to rebuilding the NSX engine.

I think part of the issue is that because the NSX is a low volume car and then on top of that the majority are not boosted and those that are, aren't pushing beyond 400 RWHP, we have a small group of cars from which to have data points.

So as with any machine there is some standard deviations to the norm and also some outliers. I.e. based on material properties and machining characteristics some may hold higher amounts of power with no issues and others may break at lower amounts of power, even with a proper tune.

In any case this has made for an interesting read.