Corey does his magic

[32valvesftw]

I picked up my 91 in March, it had Bola exhaust on it but was otherwise stock as far as I know. I removed the resonator and added an X pipe, then gave it to Corey H for headers and tune. Just got the dyno results 382 whp / 373 tq. Im impressed, I haven't driven the car yet but I can't wait to feel the difference.

[A26B]

That's about 450Hp at the crank. You'll feel that in the SOTP dyno! Tell him I said hello :-)

[FU]

Now let Corey hog out the plenum & injector housing's for 400+ RWHP.

[Paul Workman]

Yeah, it shows ta go ya just how stifled these motors are. The second gen LT5 made 550 hp on the engine dyno, according to Graham Behan.

Oh...the lost opportunities and possibilities....

[32valvesftw]

450 at the crank? I was thinking about 430, 12% drivetrain loss, but you guys have much more experience than me with these numbers.

[mike100]

There was documented evidence of factory dyno testing that showed 440 crank hp on a brake dyno when the engine had headers and an optimized tune for the '90 engines if I recall correctly. So... mid 400's is a good estimate. Headers seem to wake these cars up.

[32valvesftw]

Cool, the Corey effect adds the extra 10 hp.

[XfireZ51]

I have the utmost respect for Corey, but for a motor that starts out at ~ 335-345 rwhp stock, 40rwhp bump on headers and a tune sounds a bit high to me.
If it is there, it's outstanding work and Corey is the guy to do it.

[Billy Mild]

Comparison to the Haibeck tunes?

[Vette73]

Comparison to the Haibeck tunes?

Yes I would like to see the comparisons also....I remember when I did headers,exhaust and installed Marc's chip (was mailed to me from Chicago) I live in NY- the car def did pick up power..

450 crank horsepower? Seems a little high to me also since I'm guessing the tune is the same.....Not too familiar with the tuning process when it comes to chips........Goid luck with car...

[A26B]

It's all subjective unless the engine is tested on an engine dyno instead of a chassis dyno. It's really not that big of a deal.

[grahambehan]

Yeah, it shows ta go ya just how stifled these motors are. The second gen LT5 made 550 hp on the engine dyno, according to Graham Behan.

Oh...the lost opportunities and possibilities....


That would be 528 Hp 431 Tq.

Graham.

[32valvesftw]

First off I do not have a baseline number before the tune, I do not know much about the history of the car regarding if it had any mods. The peak power came on at about 5600, so according to Corey the plenum is probably not ported. That said I think there are always deviations in HP depending on who builds the motor. My understanding is that the LT5 is essentially a hand built motor, so there will be variation from motor to motor. In any case I agree its not a real big deal, I was just pleasantly surprised. Cant wait to drive it!

[RussMcB]

Comparison to the Haibeck tunes?It's hard to imagine one of those guys having a way better tune than the other.

[Vette73]

First off I do not have a baseline number before the tune, I do not know much about the history of the car regarding if it had any mods. The peak power came on at about 5600, so according to Corey the plenum is probably not ported. That said I think there are always deviations in HP depending on who builds the motor. My understanding is that the LT5 is essentially a hand built motor, so there will be variation from motor to motor. In any case I agree its not a real big deal, I was just pleasantly surprised. Cant wait to drive it!

Yes from what I understand they were all hand built...My theory is if there all the same displacement same cams same valves same spark plugs,I would tend to believe they would basically perform the same....I'm sure after they were assembled they had to be checked for proper compression and just basic assembly...

Let us know how you like it when you drive it..Safe driving...

[32valvesftw]

It was also usually chilly when she was on the dyno. So there is that.

[XfireZ51]

A tune AND headers isn't additive. The headers are going to add hp by reducing restriction in the exhaust. A "tune" will take advantage of the modification, it won't "add" horsepower beyond what the exhaust modification makes possible.
As Jerry stated, this is subjective given the fact that Dino's, even of the same make, can have significantly different results. Dyno results are valuable from the standpoint of establishing a benchmark, and then tracking changes and the results of those changes.

[1990 quasar blue]

Could be the correction factor. Maybe STD as opposed to SAE. Regardless, congrats on the new power.
Porting the plenum and injector housings will compliment those headers nicely. :cheers:

[XfireZ51]

Could be the correction factor. Maybe STD as opposed to SAE. Regardless, congrats on the new power.
Porting the plenum and injector housings will compliment those headers nicely. :cheers:

Frankly, that should be stated. For the most part, people that post dyno results use SAE. I know I do, and pretty sure Marc does. A dyno chart would be nice to see to determine the basis used for measurement.
Having said that, the upgrade in power is like scuba diving "rapture of the deep".
The further you travel down, the further you want to travel down. Power is intoxicating and the LT-5, at 500hp+ levels really is a blast. ENJOY!

[Paul Workman]

That would be 528 Hp 431 Tq.

Graham.

Thanks for that correction, Graham.:)

[XfireZ51]

Graham,

Any thoughts on the Mercury Marine heads mated to an LSx block?

[grahambehan]

Graham,

Any thoughts on the Mercury Marine heads mated to an LSx block?

Should be good if they ever get to fruition, I hope they do and look forward to working on such an engine.

Graham.

[XfireZ51]

Should be good if they ever get to fruition, I hope they do and look forward to working on such an engine.

Graham.Would make for an interesting alternative to the LT-5.

[grahambehan]

Just a few comments on information stated earlier in this thread:

The LT5 was a premium fuel recommended application, so the production released ignition timing was about 5 degrees from borderline detonation.

In test 1 form, as installed in vehicle with vehicle intake, exhaust and calibration the 1993 engine made 405 hp SAE corrected.

In test 20 form, max potential, with open inlet, headers and LBT/MBT it made 445 hp.

So there is easy power to be made from ignition timing and fuel on a stock system, add headers and more timing can be added, reducing back pressure tends to make the knock limit higher.

Graham.

[XfireZ51]

Graham,

When dyno tuning my motor, I have found that knock appears to occur at ~4500-5500rpm range. However, beyond that the LT-5 appears to be knock tolerant. I've had WOT timing up around 34-35d with no indication of knock occurring at that level. Just a loss of power. AFR is ~ 12.8:1. How does that square w your experience and expectations?

[grahambehan]

On 93 octane fuel I would agree with the above.

Graham.

[XfireZ51]

On 93 octane fuel I would agree with the above.

Graham.

Yes it's 93 Octane 10% Ethanol. Which brings up the question of doing E85 on an LT-5.¢

[Fully Vetted]

I picked up my 91 in March, it had Bola exhaust on it but was otherwise stock as far as I know. I removed the resonator and added an X pipe, then gave it to Corey H for headers and tune. Just got the dyno results 382 whp / 373 tq. Im impressed, I haven't driven the car yet but I can't wait to feel the difference.

Congrats! Yes, Corey is def an ace when it comes to tuning. We're fortunate to have him in our backyard. You'll love the difference.

[32valvesftw]

The tires do appear to be slipperier, than they were before.