How dyno numbers are utilized by ITAC

[Bob Roth]

I believe the thing the ITAC criteria misses is considering the original hp per liter. Sure a 105 hp 9 to 1, 16 valve honda CRX that was limited to 6500 rpm might be bumped up to 130 hp with at 7500 rpm and headers and tuning. So big deal, its now .85 hp per liter.

The problem with the rules is how they treat an engine that is already 8200 hp readline and 1 hp per liter such as the the 99 civic si, del sol VTEC, S2000 or teg type R. How do these engines get to 1.25 hp per liter? Do you expect them to rev to 10,200?

My point is the ITAC assumes all engines can get to about.,9 hp per liter under the rules, the problem is cars shipped with engines at 1 hp per liter such as Honda S2000, VTEC or Type R are really badly classified. As the rules sit today, these cars have little development potential.and in fact are classed about a class above their potential when considered on a hp basis.

[JoshS]

The problem with the rules is how they treat an engine that is already 8200 hp readline and 1 hp per liter such as the the 99 civic si, del sol VTEC, S2000 or teg type R. How do these engines get to 1.25 hp per liter? Do you expect them to rev to 10,200?

This is why it is a process, not a formula. Those cars are not expected to get a 25% gain, or in some cases they get a weight break based on torque or displacement, or sometimes both.

[JeffYoung]

There is some truth to this but it doesn't hold water in all cases.

Case in point: Integra GSR. 1.8 liters and 170 hp stock. 185 whp or so in IT trim. Doing just fine.

Josh's point holds. If you can show that your motor does not make the expected gain, an adjustment will be considered.

I believe the thing the ITAC criteria misses is considering the original hp per liter. Sure a 105 hp 9 to 1, 16 valve honda CRX that was limited to 6500 rpm might be bumped up to 130 hp with at 7500 rpm and headers and tuning. So big deal, its now .85 hp per liter.

The problem with the rules is how they treat an engine that is already 8200 hp readline and 1 hp per liter such as the the 99 civic si, del sol VTEC, S2000 or teg type R. How do these engines get to 1.25 hp per liter? Do you expect them to rev to 10,200?

My point is the ITAC assumes all engines can get to about.,9 hp per liter under the rules, the problem is cars shipped with engines at 1 hp per liter such as Honda S2000, VTEC or Type R are really badly classified. As the rules sit today, these cars have little development potential.and in fact are classed about a class above their potential when considered on a hp basis.

[gran racing]

So without several dyno sheets being submitted with full builds, is there much value in one dyno plot? Seems like there needs to be a lot of trust and respect on both ends.

[Andy Bettencourt]

There is some truth to this but it doesn't hold water in all cases.

Case in point: Integra GSR. 1.8 liters and 170 hp stock. 185 whp or so in IT trim. Doing just fine.

Josh's point holds. If you can show that your motor does not make the expected gain, an adjustment will be considered.

Do you think a letter would get consideration for STOCK hp/liter? This car has a 1.6 and makes 160hp. Very similar to the S2000 and Type R, both that were seemingly accurately classes below 25%.

[JeffYoung]

Nope (at least for me) because we don't know what the gain might be. It could be a high revving low displacement motor that responds well to IT mods (the GSR motor) or one that does not (apparently the S2000 motor).

There does not seem to be a hard and fast rule in practice as Mr. Roth would suggest.

Do you think a letter would get consideration for STOCK hp/liter? This car has a 1.6 and makes 160hp. Very similar to the S2000 and Type R, both that were seemingly accurately classes below 25%.

[Chip42]

stock volumetric efficiency is not always a good indicator of IT Ve. it's a good gut check but not a good predictor using "expected" numbers. it's all about the efficiency of the system, and the resultant output will be driven by the weakest link. how IT allowances change this system tends to drive the gain over stock - if you replace a poor manifold wiht a good one, you will see more gains than replacing a good manifold with a very good one. if the head is crap, no amount of exhaust work will get you to 90% volumetric efficiency.

it's about as useful as expected gains, though, as they really are basically the same thing. the math on gains is easier to run and more digestable, so The Process, as is, is both just as good and easier to work with.

I can tell you from experience that a 20% gain on a B16 in ITS trim is not out of the question. 25% might be optimistic, but bolt ons will take it to ~15%+ assuming a 15% driveline loss.

as you noted, though Ve tends to be inversely proportional to displacement, or really a function of RPM. peak output of a well designed system will fall along a line for bhp/l vs RPM, but we can't use that as a universal predictor in IT.

my own car (AW11 MR2) breaks from the "norm" so I'm sensitive to the fact that all of these predictive mechanisms are general rules, NOT universal truths.

general gut check values I use:

a fixed cam car can often make as much as ~0.8-0.9 hp/L. age and displacement tend to drive the maximum for a given engine.

fixed profile, variable timing cams will typically inch this up by ~0.05-0.1

multi-profile cams or variable lift systems (VTEC, VVTLi) can often see 1.0-1.15+

[bamfp]

There is some truth to this but it doesn't hold water in all cases.

Case in point: Integra GSR. 1.8 liters and 170 hp stock. 185 whp or so in IT trim. Doing just fine.

Josh's point holds. If you can show that your motor does not make the expected gain, an adjustment will be considered.

I can tell you that we are making nowhere near 185 whp with Zsolt's GSR. We have not taken it to the "happy" dyno yet. But on my Dynojet at work and the Dynopac it is under 170whp. No BS.

[Greg Amy]

With 10.9:1 compression, better-than-stock cams (but not STL-optimized), titanium springs and retainers, and adjustable cam gears (otherwise, an ITS legal engine) we were making 186whp on a Dyno Dynamics (well, before the crappy cam gear broke, anyway).

And although we are currently about 150 pounds lighter than an ITS Acura Integra GSR, I've twice lost STL lap records (and two races) to ITS-legal Mazda RX-7s (Lime Rock and New Hampshire).

I'd careful out there on that Island Of Conclusions you're jumping to...

On edit: also forgot to mention that we removed the GS-R's intake manifold butterfly/plate (no clue if it makes a difference), disabled all the intake manifold/throttle body coolant hoses, and we're also running an aluminum flywheel. And, to the chassis performance, we're also running an ITS non-compliant close-ratio Integra Type R gearbox (OS Giken LSD). All this, and I'm still friggin fighting with ITS RX-7s...maybe I just suck...

[Jeremy Billiel]

Our ITS GSR just before it blew up (i.e making its peak power being loose) made 168 WHP on a dynopak.... A VERY long way from 185 WHP

In ITS you will NEVER, EVER get to 185 WHP

The notion that GSR's take well to mods is laughable... 15-20% gains is all you will get.

[gran racing]

18 HP difference between the two dynos? Or were there other differences from one reading to the next?

[Jeremy Billiel]

18 HP difference between the two dynos? Or were there other differences from one reading to the next?

Two different engines dave

ITS Trim: 168 WHP dynapak
STL Trim: 185WHP dyno dynamics

[Greg Amy]

I am referring to this year's STL engine with all those listed mods, the one I lost at Watkins Glen last weekend due to cam gear failure. That dyno tuning and testing was done at Xenocron's Dyno Dynamics dyno the Friday before the MARRS4 weekend.

Billiel is (awkwardly) referring to last year's ITS-legal engine, the one that we lost the oil pump on at the 2010 Runoffs. His dyno numbers are from Kessler's Dynapack.

[JeffYoung]

Zsolt told me higher numbers, but I don't want to get into an internet discussion about it.

I've been on track against that car and fast ITS legal RX7s and it's not hurting for power. I think its aero top end helps it, but it isn't loosing races to the Steve Eckerich and Kent Thompsons and Chuck Hines of the world due to power. Helll the vid of Zsolt rolling Chuck on the backstretch at RA was pretty damn impressive.

FWIW, my peak number is 181, but most pulls were high 170s, and I run at 2670, and Zsolt and my car are very close on the straight.

I can tell you that we are making nowhere near 185 whp with Zsolt's GSR. We have not taken it to the "happy" dyno yet. But on my Dynojet at work and the Dynopac it is under 170whp. No BS.

[JeffYoung]

Jeremy it's impossible for me to take that seriously when you didn't even try on the ITS motor.

Our ITS GSR just before it blew up (i.e making its peak power being loose) made 168 WHP on a dynopak.... A VERY long way from 185 WHP

In ITS you will NEVER, EVER get to 185 WHP

The notion that GSR's take well to mods is laughable... 15-20% gains is all you will get.

[Jeremy Billiel]

Jeremy it's impossible for me to take that seriously when you didn't even try on the ITS motor.

Thats fine. Use Blake/Zolts number. Same HP. Why? Because GSR's do NOT take to modifications easily.

Don't kill us just because Greg and I saw the writing on the wall and that the motor was not going to make that kind of power. Blake/Zsolt have done more development and spent more money and are still in the same range for hp.

[JeffYoung]

I'm not trying to kill anybody. I understand you guys made a call based on what you believed to be true about the ITS GSR.

I just don't think that conclusion is accurate. Scott Seck's car wins races against some of the best ITS RX7s at Daytona, a pure power track. Zsolt's car runs the straights just fine with my car, and other cars that I know make 170+ whp.

The GSR is not at a power deficiency in ITS.

Thats fine. Use Blake/Zolts number. Same HP. Why? Because GSR's do NOT take to modifications easily.

Don't kill us just because Greg and I saw the writing on the wall and that the motor was not going to make that kind of power. Blake/Zsolt have done more development and spent more money and are still in the same range for hp.

[Jeremy Billiel]

Jeff - This discussion had nothing to do with on track performance....

And I quote "Case in point: Integra GSR. 1.8 liters and 170 hp stock. 185 whp or so in IT trim. Doing just fine."

Your statement is just flat out WRONG. It may be ok on the track for other reasons (I don't buy it), but this conversation started because you are making blanket hp statements that are crazy. This exact statement is what makes all the IT membrship pissed off when dyno sheets and projected hp numbers come into play.

Show me a full out ITS GSR build that makes a 185 WHP. I know what Scott's makes and its not even close....

[Greg Amy]

Jeff, you have my encouragement to say "I told you so" when an Acura Integra GS-R is pulling 1:39s at Road Atlanta. Or, maybe when an Acura Integra GS-R is keeping up with the BMW E46s up here in the Northeast (the ones that are setting lap records and are usually winning overall in the ITS/ITR group.) I'll even personally buy - and bring to you - that six-pack of your favorite beverage to drink while watching me eat my hat.

Remember, there's a much bigger world out there than a few tracks in the Southeast...just sayin'...

GA

[JeffYoung]

Turn around is fair game -- there is a bigger world out there than LRP and Pocono and Watkins Glen. Those "few tracks in the Southeast" include places where some of the very best RX7s and Z cars run (we do not have the E46s you guys do in ITS).

I'm confident that the GSR is one of the cars to have in ITS, and I'm confident it can make north of 180 whp. I wouldn't "vote" that way on the ITCS without data to back it up, but from what I've seen that's my personal conclusion and I think it is based on better experience than Jeremy's honestly.

I've heard the GSR guys say they think it can run 1:40 at RA. There is only one car/driver combo that runs under that recently, and I think anyone who looks at that situation objectively will admit it's the driver and not the car responsible for it.

The GSR is not at a power deficit in ITS. In fact, whether it is aero or power, from what I've seen, there is not a faster car in ITS above 125 (although I've not seen the ITS E46s).

May not be at a 100% "I told you so" place right now, but we are rounding third and headed for home.

Jeff, you have my encouragement to say "I told you so" when an Acura Integra GS-R is pulling 1:39s at Road Atlanta. Or, maybe when an Acura Integra GS-R is keeping up with the BMW E46s up here in the Northeast (the ones that are setting lap records and are usually winning overall in the ITS/ITR group.) I'll even personally buy - and bring to you - that six-pack of your favorite beverage to drink while watching me eat my hat.

Remember, there's a much bigger world out there than a few tracks in the Southeast...just sayin'...

GA