guess my horsepower

[bruce91nsx]

I live in Boulder, Colorado... altitude 5,400 feet.

I installed the CT whipple through a group buy here on Prime maybe three years ago, added high boost, then AEM/FIC... and must add as background that my NSX is a daily driver that does a lot of track time on some of the best-known tracks in the country, but only club events.

Current dyno results below.

Max boost something around 7lbs, max torque around 255, max HP around 325.


I went to NSXPO in Portland, and Shad dynoed my car. Exact same setup, but had to shut it down at 6K rpm because my 370 injectors could not compensate for sea level air... much too lean, but achieved 10lbs of boost.... all we could do*was try to increase base fuel pressure, given the time available.

Here is that dyno in Portland at sea level A/F with torque; HP was 331, again, shutting it down at 6K

So... what can I do to achieve 10lbs of boost at an altitude that robs perhaps 2-3 lbs of boost versus sea level?

This is being installed this weekend:

...courtesy of Ken Sampson. It's a 2.3L whipple.

And... so is this, courtesy of Shad...

It's a custom intake made by Comptech specifically for a 2.3L whipple sometime in the mid-90s. I am proud to have it!

AND 550 INJECTORS.

(sorry, don't have pix of the 550 injectors.)

I have had countless conversations with Ken, Shad and titaniumdave about this setup... really, some very intense conversations. One of the first things Shad said was: "Why are you doing this?" My answer, which he accepted, was that I am spinning the l.6L whipple as fast as it can go, with fuel and timing management, but the best it can output at this altitude is less than 330hp. I have run out of options (and.. with a 2.3L whipple, I am suddenly opened up to many future modifications).

Ken had this 2.3L on a 3.2L with low compression pistons

Dave runs a different type of 2.3L with low compression pistons on a 3.0 liter engine..

I am going to run this with a stock 3.0 engine.

Science of Speed has come up with a new SC package that uses a 2.1L SC 8.5-9 PSI to achieve 380 wheel horsepower (also stock engine, but with*many options beyond that as well)
http://www.nsxprime.com/forums/showthread.php?t=116341

So... what's your best guess what my horsepower will be? I've given several hints.

I will not know myself until some time next week.

--bruce

 

[WillErickson]

So are you using some sort of custom pulley to achieve a specific boost target?

 

[bruce91nsx]

So are you using some sort of custom pulley to achieve a specific boost target?

I am going to use the CT high boost pulley that is currently on my 1.6L whipple as a starting point... I also have another one available is someone is interested....
--bruce

 

[Cozmo]

Put me down for 375. I have nothing to base that on but random guessing. :wink:

 

[BadCarma]

I am going to use the CT high boost pulley that is currently on my 1.6L whipple as a starting point... I also have another one available is someone is interested....
--bruce

dude, I remember your setup. you are living dangerous my man.

 

[bruce91nsx]

dude, I remember your setup. you are living dangerous my man.

Can you elaborate?

Anyway... doing some searching, I came across this site:
http://www.anycalculator.com/enginehorsepower.htm

which states:
"Elevation plays the biggest single role in the horsepower/performance equation. For every 1000 feet you climb above sea level, there is a reduction in air density of approximately 4.5 percent. So, for every 1000-foot gain in altitude, there is a corresponding loss of horsepower."

At my altitude, about 5,400 feet, this would amount to a 24.3 percent reduction in air density. The 2.3L Whipple moves about 30% more air than the 1.6L Whipple....

If I get about 7 lbs of boost at my altitude with the 1.6L Whipple, and about 10 lbs at sea level... I should be in the ballpark of 10lbs with the 2.3L Whipple at my altitude. I also have a larger pulley if needed, and we will be adjusting air/fuel with the F/IC.

Don't know if these are valid mathematical comparisons, but they seem to make sense.

--bruce

 

[swerve2007]

there is no reason why you couldn't adjust for altitude by raising boost- aircraft engines have done it for ages. since your only adjustment is mechanical (and a tune of course) you should be ok as long as you stay at that altitude.

 

[BadCarma]

his car is tuned for 5000 feet, the issue is one that has been beat to death and is two-fold:
stock engine or built with turbo n20 SC
safety system ensuring no 'severe detonation. 7 psi is safe as hell with a basic tune but not more imho....I should have let it go. sorry bruce. sounds like a case of speak before read all of postitis. you seem methodical enough.but isnt your car an automatic?

best regards david

 

[bruce91nsx]

his car is tuned for 5000 feet, the issue is one that has been beat to death and is two-fold:
stock engine or built with turbo n20 SC
safety system ensuring no 'severe detonation. 7 psi is safe as hell with a basic tune but not more imho....I should have let it go. sorry bruce. sounds like a case of speak before read all of postitis. you seem methodical enough.but isnt your car an automatic?

best regards david

Thanks, David, and I have read through all of the great work you have done with nos. The car is a five-speed manual, and I also have water/meth.

We have done a CAD of the new adapter plate and built one out of wood. Fits perfect, so we are proceeding (not with the wood piece, though :wink

--bruce

 

[bruce91nsx]

Getting closer.....

You can see the new adapter plate under the charger. The new charger is longer than the 1.6l whipple, so there wasn't room for the stock airbox.
Had to fabricate: the air filter tube and relocate the meth injection; a new mount plate for the electronic control box that used to reside under the old blower with a heat sink; throttle cable bracket; bypass tube; and had to relocate/lengthen two parts of the wire harness that ran too close to the blower.

The work is being done by Tobi Connell (formerly TC Performance) in Arvada, Colo., who did my F/IC install about a year ago and does just awesome, awesome work.

 

[bruce91nsx]

... switching to the larger pulley ...

We are going to use the low-boost from the original Comptech install. Tobi said he was having to pull too much timing with the high-boost pulley in the initial tuning. He was hitting up to 11 lbs of boost at 6K rpm while keeping fuel very rich with the new 550 injectors to keep things safe and felt it was too much. He was hitting 345 hp and 290 torque at 6k, though. I'm guessing we'll hit a max 9 lbs with the larger pulley and will be safer.

That would put me in the realm of Racerxjling (see http://www.nsxprime.com/forums/showthread.php?t=113144), who hit 427 hp and 284 torque at 9 lbs. I'm thinking that I probably won't reach those numbers with my car, but should know later this week.

--bruce

 

[SOURCE 1]

safely?
398hp and 281tq

 

[bruce91nsx]

I am quite pleased to achieve these levels of hp and tq at this altitude; once again I must thank Tobi, Ken, Shad, titaniumdave.

I've been looking over and over again about the linear hp, and the very straight line of torque.

Looks like a good tune to me, but I'd sure like to hear from you all about what you think.

I pick up the car Saturday, and might be inclined to post here about my observations then, but might better spend my time driving for hours through the mountains.....
--bruce

 

[WillErickson]

I am quite pleased to achieve these levels of hp and tq at this altitude; once again I must thank Tobi, Ken, Shad, titaniumdave.

I've been looking over and over again about the linear hp, and the very straight line of torque.

Looks like a good tune to me, but I'd sure like to hear from you all about what you think.

I pick up the car Saturday, and might be inclined to post here about my observations then, but might better spend my time driving for hours through the mountains.....
--bruce

Holy crap Bruce! I'm jealous!

What was max boost on this run? Do you have a boost plot?

 

[bruce91nsx]

Holy crap Bruce! I'm jealous!

What was max boost on this run? Do you have a boost plot?

I will post boost and a/f graphs as soon as I get them... but I am hitting maybe 9.5-10 psi across the rev range, with no detonation!!!

I just love the F/IC, and Tobi's expertise....

--bruce

 

[SOURCE 1]

I was off by 4 on both! Damn

I would like to see all the Af/r when you get thm

 

[bruce91nsx]

Here's the a/f:

 

[SOURCE 1]

Good deal thanks for sharing!

Have fun with that beast!

 

[latzke]

Nice job. I can't wait to take her for a drive. :wink:

Looks great.

Given your choice of engine cover...get a cover for your coolant bottle or cover the top half with some kind of coating or the UV will cause it to age/fail prematurely...especially at this altitude...especially since it's a daily driver.

 

[bruce91nsx]

I was off by 4 on both! Damn

I would like to see all the Af/r when you get thm

Man, that was close!!!!
--bruce

 

[bruce91nsx]

Nice job. I can't wait to take her for a drive. :wink:

Looks great.

Given your choice of engine cover...get a cover for your coolant bottle or cover the top half with some kind of coating or the UV will cause it to age/fail prematurely...especially at this altitude...especially since it's a daily driver.

Thanks!
What I really like is that I am at about 250 tq at about 2,700 rpm, then the torque curve shoots straight across the revs... straight as someone firing a bullet! My previous max torque was 255!

Ready for a Ride through the Rockies!

...and, yeah.... I'm on my second coolant tank since I put that cover on.....

....and... congrats on your new daughter!

--bruce

 

[ffffanman]

So let me ask you and confirm.
You are running a 3.0 engine and had originally a 1.6 whipple.
You said you where running the high boost pulley.
There where 4 pulleys made for this whipple.
For the 3.0 engine we had a 4.2 low boost and a 4.0 high boost.
Is the 4.0 the pulley you had just before the change to the bigger whipple?
The two next smaller pulleys where for the 3.2 engine and where 3.8 for low boost and 3.6 for high boost.
I have the 3.8 on my 91 and 1.6 whipple now and hit 8.5 psi at 2200 feet.
Friend has the 3.6 and hits 10.5 here as well.
Did you ever try these two 3.2 litre pulleys before you started the big makeover?
Thanks
Nice numbers sir.
Trev

 

[bruce91nsx]

So let me ask you and confirm.
You are running a 3.0 engine and had originally a 1.6 whipple.
You said you where running the high boost pulley.
There where 4 pulleys made for this whipple.
For the 3.0 engine we had a 4.2 low boost and a 4.0 high boost.
Is the 4.0 the pulley you had just before the change to the bigger whipple?
The two next smaller pulleys where for the 3.2 engine and where 3.8 for low boost and 3.6 for high boost.
I have the 3.8 on my 91 and 1.6 whipple now and hit 8.5 psi at 2200 feet.
Friend has the 3.6 and hits 10.5 here as well.
Did you ever try these two 3.2 litre pulleys before you started the big makeover?
Thanks
Nice numbers sir.
Trev

Trev:
Thanks!

I had the Science of Speed 88mm pulley, which (according to a conversion calculator) is 3.46456 inches (see http://www.scienceofspeed.com/produ...SX/ScienceofSpeed/Comptech_high_boost_pulley/) on my 1.6L Whipple, and that's what I started with on the 2.3L... but it was generating too much boost to tune safely.

With the 88mm pulley on the 1.6L, I was getting about 7.2 pounds of boost at my altitude, and hit 10 lbs with it at sea level.

I think I have now found a sweet spot with the 4.2 inch pulley on this setup... i do not think I would go smaller here without low-compression pistons.

cheers,
--bruce