SIR TEST RESULTS

[Greg Amy]

Oh, pardon me; did I wander into the Bimmerworld Forums again by mistake...?

[mlytle]

Oh, pardon me; did I wander into the Bimmerworld Forums again by mistake...?
[/b]

that would be the bimmerforums, and geez, i hope not!

[Ron Earp]

How about using a single dyno and running the same car with and without restrictor within minutes of one another? I'd love to oversee one of those tests.

Hey, I'll cover the costs if anyone wants to bring their BMW to the Dynojet in Raleigh NC. Haywood's Custom Speed shop, used it a number of times for various street cars as well as IT cars. $100 an hour, no limit to pulls for the hour. I'll pay, you bring the car well-prepped BMW 325, you bring the SIR. Think there are more than a few top running candidates in the area. I'll be there, Jeff Young will be there, and any other local IT'er that wants to check it out. Be an interesting test conducted by a non-involved indivdual(s).

R

[lateapex911]

OK, guys, I am almost finished shoveling, so.....

First, the CRB is on your side. They are not going to make any decision that could endanger the competiveness of the E36. If it means pushing back the implementation date, then they are open to that. I like your comment DJ, about radicals and rationals. What I saw this weekend was the CRB being very rational, and bending over backwards to get this resolved properly. I know that we got off on the wrong foot with the timing and the lack of data.....the CRB and the ITAC agree, and are going to attend to those issues.

Second, this is a tricky bit of business, as has been pointed out. Where do results come from? If I had MY way, I would hire Sunbelt to build me a top notch legal motor, and then go testing, with lots of SIRs, application parts, and on every dyno I could find. I would end up with a ton of data points and a lot of confidence in my final decision.

But this is the real world. So we are relying on an effort that is being put forth by members of the CRB, the ITAC guys, and actual competitors, like yourselves. Obviously, it's a difficult process, and to some degree, judgement and trust are part of the formula.

So, we are pressing forward with an evolving plan to aquire as many data points as possible.

This weekend was a major step, and we got to do some good back to back to back testing of various setups, and we owe a debt of gratitude to a competitor and a CRB member who opened his personal shop up for the day so we could make noise and burn gas.

One downside to the testing is that we are using real guys and real cars, and their privacy needs to be respected when requested. Another is that of course, no two dynos are created equal. Another reason we are trying to get many data points.

We have scheduled another test this coming weekend, with a different car, and a different size SIR, then, the weekend after that, we will be back at it with more SIR sizes, plus the ones already tested for repeatability, and at this point it looks like we will have the car we tested this weekend, AND another car.

At that pont, we will have a better picture, and can make more decisions. I have a further plan in mind, but I am not sure of it's liklihood, as it is rather ambitious.

I hear what you guys are saying about repeatabilty, legality concerns, and so on, and I assure you that we will do the best we can. I can promise that the effort will be far and above anything IT has ever seen.

Now, I know you want data and numbers, but at this point I can't release them. I can say that we see the need to do more testing, as the numbers that we have gotten so far from various sources are not showing the repeatability that is desired.

This is a process, and we are at the begining, with much more to come.

The dyno used in this test was a Clayton, a roller based chassis dyno. It uses lighter rollers, and the standard procedure is to bring the car up to speed, then drag it down, gradually increasing the load. It will not be the only type used, as we have scheduled testing on other makes as I mentioned above.

Stay tuned!

[dj10]

The dyno used in this test was a Clayton, a roller based chassis dyno. It uses lighter rollers, and the standard procedure is to bring the car up to speed, then drag it down, gradually increasing the load. It will not be the only type used, as we have scheduled testing on other makes as I mentioned above.

Stay tuned!
[/b]

Jake, From what i know, correct me if I'm wrong, the 2 most common dynos are dynojet and mustang? I heard mustang dyno read low and dynojets read high. If we are to shoot for a target hp reading wouldn't we need to use 1 or the other or both if we have a conversion scale. NASA uses all dyno jet and uses a 14.5 weight/hp ratio. Maybe this is the way to go?.
Having seen the results Jake, I think you should post what ever results you have BUT PLEASE also post your conclusions as well. You just told us you want to do another test we will abide by that. I'd like to see your pictures if you have any.
Thanks
dj

[Ron Earp]

Jake, From what i know, correct me if I'm wrong, the 2 most common dynos are dynojet and mustang? I heard mustang dyno read low and dynojets read high
dj
[/b]

This is essentially correct. The Dynojet reads higher than the Mustang dyno might be a more correct way to say it because the Dynojet seems to jive pretty well with published stock hp figures. Could be Mustangs read low while Dynojets are about right.

Anyway, Dynojets are by far the most popular of the two and can be found all over. Never heard of a Clayton dyno. I understand the logistical challenge of doing something like this, but, if you are not going to use an instrument that folks know and understand, then you are opening the entire procedure up to ridicule and nitpicking. In the end you might not have buy in from the people that matter, the BMW drivers. But, you might not have buy in from them anyhow.

Anyone wants to do tests in Raleigh I'll buy.

Ron

[Joe Harlan]

This is essentially correct. The Dynojet reads higher than the Mustang dyno might be a more correct way to say it because the Dynojet seems to jive pretty well with published stock hp figures. Could be Mustangs read low while Dynojets are about right.

Anyway, Dynojets are by far the most popular of the two and can be found all over. Never heard of a Clayton dyno. I understand the logistical challenge of doing something like this, but, if you are not going to use an instrument that folks know and understand, then you are opening the entire procedure up to ridicule and nitpicking. In the end you might not have buy in from the people that matter, the BMW drivers. But, you might not have buy in from them anyhow.

Anyone wants to do tests in Raleigh I'll buy.

Ron
[/b]

If my memory is correct the Dynojet is an inertia type dyno (with optional eddy loadcell) The mustang is a single or double roller type dyno with the eddy loadcell standard. The Clayton is normally a double roller loadable type dyno that works much like a water break engine dyno. All of them are good for reading peak numbers and should be pretty close in those numbers. I would not bother going to a dyno shop that cannot load and hold individual rpm ranges for proper tuning of those rpm and load ranges. Clayton is the old grand daddy of dynos and have always been good units. I would have no problem with results from this type of dyno.

[gpeluso]

Joe,
Glad you think it's a good dyno,but that not what Ron,DJ,and myself are talking about. We are talking about comparing apples to apples. Many HP numbers have been thrown around. AB, talked about an RX7 putting out 182 whp. I'm concerned that the goal itself maybe flawed with 220chp. If that is the goal the BMW would seem heavy. It just seemed like on Friday this information was going to be very open. Time is not on your side. I really seem to like someone like Ron helping out. He seems like a voicce of reason.

Greg

If my memory is correct the Dynojet is an inertia type dyno (with optional eddy loadcell) The mustang is a single or double roller type dyno with the eddy loadcell standard. The Clayton is normally a double roller loadable type dyno that works much like a water break engine dyno. All of them are good for reading peak numbers and should be pretty close in those numbers. I would not bother going to a dyno shop that cannot load and hold individual rpm ranges for proper tuning of those rpm and load ranges. Clayton is the old grand daddy of dynos and have always been good units. I would have no problem with results from this type of dyno.
[/b]

[lateapex911]

Well, good points on the different dynos, and we are aware of them, and we would love to run the full set of tests on all of them, LOL. Sadly practicality does enter the equation, but the results will be interpolated, and testing on different types of dynos is part of the plan. And DJ, not just one more test, but many more pulls. We did about 4 or 5 hours on Saturday.

Ron, back to back has already been done, and will be done again, numerous times. I like your offer! I encourage any and everyone to take Ron up on it.

Pictures! I forgot! lets see what I have...
The first pic it the opening, then the exit. The third is a view of the assembled unit, the sizing insert is alongside.

hmmmm. picture posting issues..lets try that again.

odd...i have done this before with success...but it isn't working now.

[dj10]

Well, good points on the different dynos, and we are aware of them, and we would love to run the full set of tests on all of them, LOL. Sadly practicality does enter the equation, but the results will be interpolated, and testing on different types of dynos is part of the plan. And DJ, not just one more test, but many more pulls. We did about 4 or 5 hours on Saturday.
[/b]

Jake, I didn't mean you should test on all the different dynos, I brought that up to show everyone that there are differences and no one should be blind to this. Example: if I'm 181 rwhp on a mustang dyno I might be 195 rwhp on a dynojet. The SIR is limiting us to 220 CHP if you calculate this is 180.4 rwhp using the 18% crank to rear wheel loss. So the target number of 220 CHP came from where and which dyno, if any? If the rx7's are using, as another example, a mustang dyno and the SIR is based on a dynojet, we would get killed.
If you won't give us any info about Sat. tests at least give us your personal conclusions and did the SIR's you had even come close to your expectations?? Damn Jake, give us something to think about.
dj

[lateapex911]

LOL......yeah, been there, done that, never agian!

they win the prize!

[AntonioGG]

Here's an interesting thread to read about dyno differences:
http://forum.specmiata.com/cgi-bin/ultimat...0786;p=0#000000

As far as the test results...the suspense is killing me! This is worse than watching "24".

Antonio
--no dog in this hunt, but curious about the results

[MMiskoe]

This might be considered a dumb question but I'll risk that.

If there is so much riding on this testing and so much effort being put into it, why screw around w/ a chassi dyno? Although engine dynos are harder to get set up initially, they have much better ability to provide consistant numbers because of the environmental controls they can provide.

Get the SIR worked out on the engine dyno where its easy to make the changes, then do some pulls on different chassi dynos to show driveline losses & differences between dynos.

You can test forever, but if you don't cmpare apples to apples you are wasting your time.

Tell me where am I wrong in this idea.

Matt

[Andy Bettencourt]

This might be considered a dumb question but I'll risk that.

If there is so much riding on this testing and so much effort being put into it, why screw around w/ a chassi dyno? Although engine dynos are harder to get set up initially, they have much better ability to provide consistant numbers because of the environmental controls they can provide.

Get the SIR worked out on the engine dyno where its easy to make the changes, then do some pulls on different chassi dynos to show driveline losses & differences between dynos.

You can test forever, but if you don't cmpare apples to apples you are wasting your time.

Tell me where am I wrong in this idea.

Matt [/b]

Your not wrong Matt. That would be a perfect solution in a perfect world. It just may not be practical at this point.

AB

[gpeluso]

AB,
Don't ge me this perfect world shit. The SCCA should have the means and the know how to perform the test. We are not talking about thousands of dollars, and if we were the SCCA could/should do it. The Club members are paying for the ProRacing, how about some of that money come back to the club level. Some guys are spending $50,000 on cars to race. Even years ago SpeedSource wanted $36,000 for an ITS RX7. If you make rules don't act like its impossible to run tests to prove them. AB, is the SCCA a nickle and dime operation. The SCCA has the ability to reach out to many resources. The engine dyno question is a great one. Hell, put the other competitive car brands on it to show data. You form your opinions from what ever data you have, but in a PERFECT world we would have the apple to apple comparision . Don't act like this is impossible. Are you afraid that you are wrong?

Greg

Your not wrong Matt. That would be a perfect solution in a perfect world. It just may not be practical at this point.

AB
[/b]

AB,
If they have the same HP shouldn't they weight the same ?

Same crank and wheel hp for the BMW and RX-7...why is the BMW 'heavy'? If they are the same hp, do you agree or disagree that the BMW is still as good as the RX-7?


[/b]

[zracre]

AB,
Don't ge me this perfect world shit. The SCCA should have the means and the know how to perform the test. We are not talking about thousands of dollars, and if we were the SCCA could/should do it. The Club members are paying for the ProRacing, how about some of that money come back to the club level. Some guys are spending $50,000 on cars to race. Even years ago SpeedSource wanted $36,000 for an ITS RX7. If you make rules don't act like its impossible to run tests to prove them. AB, is the SCCA a nickle and dime operation. The SCCA has the ability to reach out to many resources. The engine dyno question is a great one. Hell, put the other competitive car brands on it to show data. You form your opinions from what ever data you have, but in a PERFECT world we would have the apple to apple comparision . Don't act like this is impossible. Are you afraid that you are wrong?

Greg


AB,
If they have the same HP shouldn't they weight the same ?
[/b]

good point...we pay for it...why skimp on dyno time...im sure thee are plenty of members willing to offer up their ride for dyno tuning time...IT is a bigger force than most national classes...

[Andy Bettencourt]

True, but read the last paragraph on the second page of the ITCS. Many BMW drivers have called that weight 'extreme'. I can only surmise that the CRB was trying to have the best of both worlds.

AB

[steve s]

now why couldn't our club have done this testing b4 doing the comp. adjustment ???
they could have gotten the top 5 manufacturer cars from the ARRC and done some testing with them.
that is the top 5 bmw
top 5 rx7
top 5 nissans
etc . i am sure some of them would glad for the dyno time.since the top guys were taken apart to some degree and all found to be legal they would be the best choice for this test ???
now if any camp decides not to subject their car to this testing then don't complain about the results being flawed.

[Fastfred92]

Where did the 182 whp # for the RX7 come from??? what level of prep are we talking here? Huffmasters car ??? I may be wrong but I suspect a decent prep but not motec type RX7.....

[MMiskoe]

Back to the testing process.

Testing this motor w/ different levels of prep and different types/sizes of restrictor seems like a no brainer.

So why is there any time wasted on a chassi dyno or even moreso, why any time wasted arguing about the numbers measured there. Results are only as good as the test done.

Having just jumped into reading this, I can't believe this approach hasn't been explored.

4 motors w/ different levels of build, all get run w/ the flat plate & the SIR. From what I read on the SIR it will top out the performance of the motor regardless of what else is done to it internally (curious to see this). Start at the bottom see what you get, then move up & see how it affects performance.


Motor 1 - stock, minimal if any changes - run it w/ the SIR and the flat plate
Motor 2 - moderate IT change - run it w/ the SIR and the flat plate, compare differences
Motor 3 - fullblown IT motor
Motor 4 - bump compression & better cams (to show the envelope above what can be done legally)

Then while you're at it, better get a decent, or full blown 13B motor on the stand. Probably ought to get a Datsun L28 (L28 or L24 in the 240z?) motor there too.

The idea that SCCA hasn't already done this w/ other cars somewhere between WC and TransAm would suprise me. Should be some previously done tests that can be repeated on the BWM motor.

Meanwhile there are three choices:

Send the E36 to ITE
Raise the Weight
Let them drive off into the winner circle and remember we're racing for bowling trophies.