IS300 in ITS?

[Ron Earp]

Originally posted by Andy Bettencourt@Sep 20 2005, 01:21 AM
Ron L,

Using 195 on a Mustang dyno and 18% driveline losses, what crank HP would you estimate?

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If someone were to report to me, or I would think any operator of a Dynojet dyno, that their car made 195 rwhp on a Mustang Dyno then one could reasonable assume the following, given similar (within +/- 300 ft density altitude) conditions:

*The least the car would made on a Dynojet would be 210.6 hp at peak (assuming 8% difference between Mustang and Dynojet).

*The most the car would make on a Dynojet would be 226.2 hp at peak (assuming 16% difference between Mustang and Dynojet).

You need not worry about drivetrain losses, same car, same drivetrain losses. The difference between the two has been hard to nail down, but at least a range is available. I personally have run none of my street or race cars on a Mustang Dyno, but have see some run on them before and seen the differences in peak numbers. But, don't take my word for it, all you need to do is to casually scan the various car forums (Mustang, Viper, Audi, VW, Porsche, BMW, Lightning, Lotus, GT40 etc.) to see that everyone recognizes that Mustang dynos read lower than Dynojet dynos.

If the BMW in question made 195 rwhp on a Mustang Dyno, then it is pretty stout, much stouter than Steve's RX7 in the post above and having witnessed Steve getting smoked my top notch BMWs, I know the score. I also know Steve's car is very well done and certainly represents a top RX7 build and that his car could run anywhere in the country well. Except of course, when BMWs are involved.

Anyhow, to answer your question to crank hp: I don't like flat percentages on losses due to some info I presented a few pages ago. But, if we were to take a 13% driveline loss, the number I prefer because I don't like the larger 20% figures I think them too high, then crank shaft figures are:

237 hp to 255hp, based on a conversion from Mustang to Dynojet numbers. A stout car when compared to the rest in ITS.

It's all numbers though, just look at the laptimes and see what happens, at VIR the BMWs run away with the show.

Ron

 

[Andy Bettencourt]

For the record:

Leverone's RX-7 just made 176whp and 129ft lbs on a DynoJet in Worcester, MA during our last development session. Seems in-line with Steve's car.

AB

 

[Ron Earp]

Originally posted by Andy Bettencourt@Sep 20 2005, 02:03 AM
For the record:
Leverone's RX-7 just made 176whp and 129ft lbs on a DynoJet in Worcester, MA during our last development session.  Seems in-line with Steve's car.
AB

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So using around 13% loss then he would be about 198 fwhp and 146 fw fp/lbs. Not a lot when compared to BMWs.

Ron

 

[robits325is]

It is my opinion that achieved horsepower has no relevance. Unless you can find a 100% developed example of every car in every class then get them to the same place at the same time for controlled dyno runs then this entire issue should be put to rest.

Factory horsepower ratings and curb weight should be the main factors in car classification.

following from a previous post:

1 911 T&E (70-72) 2485 175 14.20
2 Prelude non-SH (97-98) 2825 195 14.49
3 Del Sol V-tec (94-96) 2360 160 14.75
4 Calais/Achieva/Grand-Am (86-93)2655 180 14.75
5 Civic Si (99) 2360 160 14.75
6 Prelude (97-98) 2905 195 14.90
7 Corrado 2680 178 15.06
8 325 e36 (92-95) 2850 189 15.08
9 944S (87-88) 2850 188 15.16
10 Milano 3.0 (87-89) 2780 183 15.19
11 Prelude V-tec (93-96) 2905 190 15.29
12 Golf Vr6 (95-99.5) 2680 172 15.58
13 Jetta Vr6 (94-96) 2680 172 15.58
14 Cougar (99) 2650 170 15.59
15 Integra GSR (94-99) 2690 170 15.82

the following is from a previous post

ARRC 2004 - Chet 1:40.936 BMW
ARRC 2004 qual. - Ed York 1:40.890 BMW
ARRC 2001 qual. - Sylvain Tremblay 1:40.372 RX-7

If these numbers are correct then why wasn't there an uproar in 2001?

Dyno correction factors is an interesting discussion but if there is that much variation from one dyno manufacturer to another then how can these numbers be used to make competitive adjustments?

 

[lateapex911]

Veeeery interesting!

So the 210.6 lines up with the info I had....errrr scratch that, I forgot, I made it up...it's lies and fabrications according to DD..

Let's flip this another way...

First, the Dynojets are pretty polular these days, and the numbers I have heard are fairly consistant. THe RX 7 numbers are Dynojet if I'm not mistaken.

So, max hp you can squeeze from a 7 is, lets just say 180. On a Mustang that would be 165. (at the min recognized difference).

Apples to apples then that nets out to 30 hp between a 165 RX-7, and 195 Bimmer. (A not to the limit Bimmer BTW)

So, 30 hp equates to ALOT of weight difference if the cars are to be spec'ed properly . The current specs are 2680 for the 7, and 2850 for the E36. Thats 170 pounds......which is less than half what the process suggests as a starting point.

Keep in mind we're using conservative numbers...an engine that has left a little bit on the table, and the minumm conversion factors for the dyno...........

Thoughts???

 

[Andy Bettencourt]

Originally posted by robits325is@Sep 19 2005, 09:23 PM
It is my opinion that achieved horsepower has no relevance.  Unless you can find a 100% developed example of every car in every class then get them to the same place at the same time for controlled dyno runs then this entire issue should be put to rest. 

Factory horsepower ratings and curb weight should be the main factors in car classification. 

following from a previous post:

1 911 T&E (70-72) 2485 175 14.20
2 Prelude non-SH (97-98) 2825 195 14.49
3 Del Sol V-tec (94-96) 2360 160 14.75
4 Calais/Achieva/Grand-Am (86-93)2655 180 14.75
5 Civic Si (99) 2360 160 14.75
6 Prelude (97-98) 2905 195 14.90
7 Corrado 2680 178 15.06
8 325 e36 (92-95) 2850 189 15.08
9 944S (87-88) 2850 188 15.16
10 Milano 3.0 (87-89) 2780 183 15.19
11 Prelude V-tec (93-96) 2905 190 15.29
12 Golf Vr6 (95-99.5) 2680 172 15.58
13 Jetta Vr6 (94-96) 2680 172 15.58
14 Cougar (99) 2650 170 15.59
15 Integra GSR (94-99) 2690 170 15.82

the following is from a previous post

ARRC 2004 - Chet 1:40.936 BMW
ARRC 2004 qual. - Ed York 1:40.890 BMW
ARRC 2001 qual. - Sylvain Tremblay 1:40.372 RX-7

If these numbers are correct then why wasn't there an uproar in 2001?

Dyno correction factors is an interesting discussion but if there is that much variation from one dyno manufacturer to another then how can these numbers be used to make competitive adjustments?

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Rob,

While there may be some that agree with you, I couldn't be further from your outlook.

Achieved HP is EVERYTHING. Different types of motors respond differently to IT-prep. 2V, SOHC, DOHC, muti-valve, VTEC, Rotory, etc...if you pigeon-hole everyone based on advertised CW's and hp figures, you CREATE the potential for HUGE overdogs. I can't even get a grip on this train of thought.

Add to that curb weight...CURB WEIGHT? The resultant weight that makes up CW is different for each type of car. Curb weight is defined as: the weight of an automobile with standard equipment and fuel, oil, and coolant. This means that the curb weight varies between the same car with different options...and what about fuel tank size? A car with a large tank would have an 'artificially' high CW everything else being equal. That figure is irrelevant.

Minimum weight needs to be set based on performance potential. Estimating that potential is no exact science but when you run cars through the same, repeatable process - you can get close IMHO.

As far as the lap times you quote, how can you compare this stuff year to year without any data on track conditions, weather etc? This past month, the Spec Miata track record was SMASHED at NHIS during qualifying by the top 5 drivers. 2 SECONDS. Everyone was picking their jaws off the pavement...2nd run group, after big-bore, cool air, warm and clean track...absolutely PERFECT conditions. You have to compare apples to apples.

Maybe I am way off base and you can show me how these numbers can work. Help me.

AB

 

[lateapex911]

Originally posted by robits325is@Sep 19 2005, 10:23 PM
It is my opinion that achieved horsepower has no relevance.

Huh????????????

That is a sure way to get things out of whack! Car A comes with 179 hp, but is really restricted from the factory, and pops 45 more hp in race trim. Car B comes with 179 from the factory, but is tweaked to the nines, and only gets 20 in race trim. Result? car A runs away, then backpeddles thru the last half of the race.

  Unless you can find a 100% developed example of every car in every class then get them to the same place at the same time for controlled dyno runs then this entire issue should be put to rest.

You must live in a perfect world....

I don't. But I'm not going to give up because the info isn't handed to me on a silver platter, signed off by an accounting firm. No, we dig, we make comparisions, and we can glean information from a broad base of sources. Things become apparent, patterns emerge. Will we nail it to the 1/10th of a HP? Ummm no. But we want to get as close as possible, and overall, across the classes, I think we are on that path.

Factory horsepower ratings and curb weight should be the main factors in car classification. 

following from a previous post:

1 911 T&E (70-72) 2485 175 14.20
8 325 e36 (92-95) 2850 189 15.08

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Interesting list, thanks for re posting. It proves the point of why stock HP is not the best choice....

The 911 uses pre SAE HP, and only the S made that number. (Remember the ratings system changed in the 73/74 era, and stock ratings plummeted after). Some worse than others. There is no way the air cooled, mechanically injected motor can be made to gain a bunch. There is no cat to lose, the engine was pretty much tweaked from the factory. And getting the MFI to run well is a mjor challenge. Getting 165 to the ground in an E, or an S even, is a TALL order. I highly doubt it can be done. But the E36 is KNOWN to put in the neighborhood of 200+ down.

Net net?? OK, lets say, the 911 puts down 160. At it's spec weight, thats 15.5 lbs/hp

The BMW, at 2850, and being conservative, putting down 205, nets to 13.9 lbs /hp.
(And at 210 hp, it's 13.5 lbs per hp, which a 2 pound delta.)

So, thats a great example of why using stock hp isn't always the best way.

BTW, the process uses stock weight as a check, but weight is the main classing variable.

 

[zracre]

Ok i was in the reading room looking at the latest Grassroots motorsports magazine (October 2005) and I got to page 120...a direct comparison of a hotted up M3...Mustang vs. Dynojet...anyone want to look and see? :119: it also has interesting stuff on the 325...stir stir stir...hehe

 

[Bill Miller]

These terms are used as subtle attempt to diminish the relevancy of the (unpopular) data that I submitted to the SCCA. I'd like to see any popular make of car being raced that is not buying off the shelf performance parts when they are available and the best

Unpopular data? C'mon Bruce. What's 'unpopular', is that those numbers would land you 200 - 250 # of lead.

You mentioned the shop you had your car dynoed at as being a 'top BMW tuner'. How many championship winning ITS cars have they built? How many ITS lap records are held by their cars?

As Darin said, if you think that the off-the-shelf parts available for a car that's undergoing active development by multiple shops, are the 'best available', you're in for a surprise.

And I'll ask you again, how did the restrictor impact YOUR lap times?

 

[zracre]

<quote Bill Miller>You mentioned the shop you had your car dynoed at as being a 'top BMW tuner'. How many championship winning ITS cars have they built? How many ITS lap records are held by their cars?

Um i think Bruce holds the Sebring short record...

 

[ITANorm]

Originally posted by robits325is@Sep 19 2005, 09:23 PM
Unless you can find a 100% developed example of every car in every class then get them to the same place at the same time for controlled dyno runs then this entire issue should be put to rest.

Interesting you should say that - and totally OT, but . . ..

To the ITAC:

Pick a dyno somewhere in the middle of the country (Topeka, maybe - it's only a 10 hour pull for me, and it has certain uhhh. . . logistical connotations), and I'll drag my car out there. I don't think you'll find anyone who will argue that it is a less than fully prepped car - arguably the most "limit-of-the-rules" MR2 in the country. If you can get anywhere near the RWHP out of it (bring your own master tuners!) you think I should be able to get, I'll be thrilled.

Otherwise, quit with the "performance potential" BS, and drop the MR2 down to ITB.

Now, sorry for the hijack, and . . . BTT.

 

[Banzai240]

I just got home tonight so I haven't had time to catch up on this thread, but here are the dyno sheets that Mr. Shafer so graciously gave me permission to post.

Most notable on this sheet is the largely written "Baseline" across the front page, as well as the notes that indicate that this is a "Baseline run with Bimmerworld chip"... Additionally, the note that mentions that the "AFR still has some lean spots..."


This is obviously an example from a car that has yet to achieve full potential, and yet it still produces a wide powerband and 194.37HP... Now, this dyno may read high, or this dyno may read low, but one thing is certain... It was accurate enough for Mr. Shafer to believe it would prove his point in the note I prevously posted from him to the CRB... That same degree of confidence is what I have that it's a good example of an average car that still has some HP left to find... Something that vast majority of BMW examples we are likely to have in common... Perhaps this decribes many of you attacking the CRB/ITAC on this issue???

 

[Ron Earp]

Or you might want to look at it this way:

That is a strong car if this is on a Mustang dyno, that is for sure. It is strong for a Dynojet too, stronger than anything else in the class with a table flat toque curve throughout the entire RPM range.

Even a better torque curve than Jeff's TR8, 3.5L V8. You can see a Dynojet plot of it here:

http://www.carolinaautomasters.com/dynographs/JeffTR8.JPG

It is not fully developed though and that was out first attempt, it'll do better next time we think.

Ron

 

[Bill Miller]

Thanks Ron, I was going to do that myself.

Now, take the 2nd page of data, and continue that out to 7000 rpm

 

[Andy Bettencourt]

Originally posted by ITANorm@Sep 19 2005, 11:51 PM
Interesting you should say that - and totally OT, but .  .  ..

To the ITAC:

Pick a dyno somewhere in the middle of the country (Topeka, maybe - it's only a 10 hour pull for me, and it has certain uhhh.  .  .  logistical connotations), and I'll drag my car out there.  I don't think you'll find anyone who will argue that it is a less than fully prepped car - arguably the most "limit-of-the-rules" MR2 in the country.  If you can get anywhere near the RWHP out of it (bring your own master tuners!) you think I should be able to get, I'll be thrilled.

Otherwise, quit with the "performance potential" BS, and drop the MR2 down to ITB.

Now, sorry for the hijack, and .  .  . BTT.

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You have to use an educated performance potential guesstimate when classing cars. Having said that, you also should use data that shows 'excessive' PP as well as 'limited' PP - then take those numbers into account and evaluate the situations.

As far as the MR2 and ITB, the ITAC is split on a move downward. The car is part of the current proposed tweaks to IT, however. Cross your fingers.

AB

 

[Ron Earp]

Done.

 

[Banzai240]

Originally posted by Andy Bettencourt@Sep 20 2005, 12:51 PM
As far as the MR2 and ITB, the ITAC is split on a move downward.

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I also effected by the cage rules... Can't move it down and add weight because of tubing size limitations... Any car built to the extent of the rules today would be renerered illegal if more than 10lbs was added...

 

[lateapex911]

Originally posted by ITANorm@Sep 20 2005, 12:51 AM
Interesting you should say that - and totally OT, but .  .  ..

To the ITAC:


Otherwise, quit with the "performance potential" BS, and drop the MR2 down to ITB.

Now, sorry for the hijack, and .  .  . BTT.

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Trust me Norm, I feel your pain......the RX-7 is in the same basic position.

 

[DoubleD]

Originally posted by lateapex911@Sep 19 2005, 09:24 PM
Veeeery interesting!

So the 210.6 lines up with the info I had....errrr scratch that, I forgot, I made it up...it's lies and fabrications according to DD..


Thoughts???

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Please read post #200 of this thread (bottom of page 10). If you're going to misrepresent what I've said, at least be clever about it.

 

[its66]

couldn't resist...300