SIR testing?

[MikeBlaszczak]

Did the SCCA actually test and measure the SIR setup they've mandated for the E36 cars in ITS? I've read that a lot of experience was drawn from cars in GTL -- but was a real BMW used with the restrictor setup and run at a track and timed, or run at a dyno? What were the results?

The stock air intake plumbing has a diameter of 80mm. The throttle body is about 56mm or so, so the 27mm restriction means a huge reduction in air volume. The area of the intake cross section is reduced by 66 percent!

I finally had the time to call a couple of the well-known BMW racing parts suppliers. One said that the SIR can't possibly be the right solution, and that the car won't even run with such a restriction. The other shop said they tried it and it cost them such a substantial amount of horsepower that the car isn't possibly competitive.

Both vendors said that the SCCA hadn't done their homework; that they didn't test the design and just went with a guess. Perhaps more disappointingly, neither vendor is working on a product to solve the problem! They both believe the rule will be corrected, and said they're working with the SCCA to get them to understand the issue.

Are other BMW drivers having better luck in preparing for the season?

[mlytle]

Did the SCCA actually test and measure the SIR setup they've mandated for the E36 cars in ITS? I've read that a lot of experience was drawn from cars in GTL -- but was a real BMW used with the restrictor setup and run at a track and timed, or run at a dyno? What were the results?

The stock air intake plumbing has a diameter of 80mm. The throttle body is about 56mm or so, so the 27mm restriction means a huge reduction in air volume. The area of the intake cross section is reduced by 66 percent!

I finally had the time to call a couple of the well-known BMW racing parts suppliers. One said that the SIR can't possibly be the right solution, and that the car won't even run with such a restriction. The other shop said they tried it and it cost them such a substantial amount of horsepower that the car isn't possibly competitive.

Both vendors said that the SCCA hadn't done their homework; that they didn't test the design and just went with a guess. Perhaps more disappointingly, neither vendor is working on a product to solve the problem! They both believe the rule will be corrected, and said they're working with the SCCA to get them to understand the issue.

Are other BMW drivers having better luck in preparing for the season?
[/b]

nope. scca did ZERO testing of this application on the target car before mandating us to be guinea pigs. lots of theory and extrapolation from other implentations of sirs, but no actual reality check of the mandated size on the affected car. supposedly a member of the itac was going to witness a test fit and dyno run this week, but have not heard back.

in theory, the sir should work....unfortunately, we don't race "in theory".

in talking with a number of other scca bmw drivers, there is a lot of discussion going on about moving to nasa or bmwcca. coincidence maybe, but there seems to be a bump in the number of its bmw's for sale.

marshall
racing plans on hold for 2006

[Andy Bettencourt]

Did the SCCA actually test and measure the SIR setup they've mandated for the E36 cars in ITS? I've read that a lot of experience was drawn from cars in GTL -- but was a real BMW used with the restrictor setup and run at a track and timed, or run at a dyno? What were the results?

The stock air intake plumbing has a diameter of 80mm. The throttle body is about 56mm or so, so the 27mm restriction means a huge reduction in air volume. The area of the intake cross section is reduced by 66 percent!

I finally had the time to call a couple of the well-known BMW racing parts suppliers. One said that the SIR can't possibly be the right solution, and that the car won't even run with such a restriction. The other shop said they tried it and it cost them such a substantial amount of horsepower that the car isn't possibly competitive.

Both vendors said that the SCCA hadn't done their homework; that they didn't test the design and just went with a guess. Perhaps more disappointingly, neither vendor is working on a product to solve the problem! They both believe the rule will be corrected, and said they're working with the SCCA to get them to understand the issue.

Are other BMW drivers having better luck in preparing for the season? [/b]

Mike,

First off, I personally appreciate the issues at hand. The timing is tough. The ITAC knows it and the CRB knows it. The CRB has heard the shouting and has verified agin with Finch that the 27mm SIR is the right size for the 220hp target.

Second, it is clear that you aren't fully up to speed on SIR technology. It is not simply a 66% reduction in airflow like a 27mm flat-plate would be. Two TOTALLY different technologies. When talking with "BMW Supplier" #1, who said the car wouldn't even run, it is clear that they also don't understand SIR technology, or it wasn't expalined to them properly. I can see how you could get that response if the question was "what is a 27mm restrictor plate gonna do to my power?" was the question.

Thirdly, where is the info that the second shop came up with? They tried the 27mm SIR and the results were bad? Where are they? Any interest in having them send the before and after results, plus a description of the parts they used to install the set-up? crb AT scca.com Simple.

Both vendors said the SCCA didn't do their homework? Haven't received any letter from anyone but Bimmerworld and they made no mention of having ANY experience with SIR's and no data or theory to support their skeptisism. The opposite is true with the CRB - they worked with Finch to size it and (yes, I know) in theory it (the SIR) doesn't care what application it is in.

We have ZERO letters from anyone telling us why 27mm is wrong, suggesting any 'corrections' in the context of SIR's, or helping us 'understand the issues'. Just complaints.

I will be the first one to stand up and say we screwed the pooch if the testing (which is scheduled now on an E36 and warmly accepted by anyone who actually has data) shows too much power is being taken away. I would hope all of the people who have said the CRB is crazy and the sizing is way low would stand up and say they over-reacted if/when the power numbers are correct. Frankly, if it's OVER-sized, ya'll will be the first ones to write in and say you are making too much than the target, right?

Again, I understand the timing sucks - and the perception it's a shot in the dark -but the CRB is ULTRA confident that this is sized right AND it's the right thing to do for the class/car.

AB

[MikeBlaszczak]

Second, it is clear that you aren't fully up to speed on SIR technology. It is not simply a 66% reduction in airflow like a 27mm flat-plate would be. [/b]

Of course I'm not, Andy. I'm an amateur mechanic and a club racer, not a aeronautical engineer. Anyway, I said it was a 66% reduction in the cross-section area, not a 66% reduction in flow. (You quoted it in your response, so I know you saw it.)

Any interest in having them send the before and after results, plus a description of the parts they used to install the set-up?[/b]

I don't know. Feel free to ask them.

We have ZERO letters from anyone telling us why 27mm is wrong, suggesting any 'corrections' in the context of SIR's, or helping us 'understand the issues'. Just complaints.[/b]

Conversely, where would I find information describing why 27mm is correct? I haven't seen any real help in understanding the issues; just assertions that it's correct, unbiased, and so forth.

Meanwhile, you've missed gone on about these other points and missed my most important question: I'm interested in hearing what other BMW racers are doing to prep their cars. As far as I can tell, just mounting the part requires custom fabbing duct work (to match the diameters of the SIR to the MAF), or finding a supplier who can make an SIR with the correct diameter. If I can find other drivers who are solving this same problem, it would help greatly; it's my hobby, and not my business, so having such a substantial workload dumped on me at the last moment is prohibitive.

In fact, at this point, I just can't imagine competing in ITS this year; I just don't see how I can get the fab work done, end up with something that works, aand so on, in time to have a successful season. Switching to a different class looks far easier.

[Joe Harlan]

Of course I'm not, Andy. I'm an amateur mechanic and a club racer, not a aeronautical engineer. Anyway, I said it was a 66% reduction in the cross-section area, not a 66% reduction in flow. (You quoted it in your response, so I know you saw it.)
I don't know. Feel free to ask them.
Conversely, where would I find information describing why 27mm is correct? I haven't seen any real help in understanding the issues; just assertions that it's correct, unbiased, and so forth.

Meanwhile, you've missed gone on about these other points and missed my most important question: I'm interested in hearing what other BMW racers are doing to prep their cars. As far as I can tell, just mounting the part requires custom fabbing duct work (to match the diameters of the SIR to the MAF), or finding a supplier who can make an SIR with the correct diameter. If I can find other drivers who are solving this same problem, it would help greatly; it's my hobby, and not my business, so having such a substantial workload dumped on me at the last moment is prohibitive.

In fact, at this point, I just can't imagine competing in ITS this year; I just don't see how I can get the fab work done, end up with something that works, aand so on, in time to have a successful season. Switching to a different class looks far easier.
[/b]

So Mike let me undersdtand are you saying even as an amatuer mechanic that you can't install a tube in a tube? Next I checked the SCCA results for oregon region and part of Nw region and I don't find you listed in ITS? If you race a different class is SCCA loosing your entry?

[robits325is]

So Mike let me undersdtand are you saying even as an amatuer mechanic that you can't install a tube in a tube? Next I checked the SCCA results for oregon region and part of Nw region and I don't find you listed in ITS? If you race a different class is SCCA loosing your entry?
[/b]

What a rude response. He never said he is a current ITS racer - maybe he was looking to start this year and he is turned off by the latest rule changes. The SCCA may be potentially losing future entries - why not embrace them instead of insulting them?

[Joe Harlan]

What a rude response. He never said he is a current ITS racer - maybe he was looking to start this year and he is turned off by the latest rule changes. The SCCA may be potentially losing future entries - why not embrace them instead of insulting them?
[/b]

Your right Rob It was rude even though I didn't mean tit that way. I just don't type my thoughts well. I have embraced it by trying to give some help on placement and parts in the other thread. What you don't understand is I know where Mike races and it's not SCCA so saying he is considering taking his ball and playing some where else is a little bit off the point. My shop is 4 hours south and I first offered several free hours of help and even a trip the dyno. So please don't get in my face about not offering help or trying to run folks off. People just need to be a bit more honest when they say the threaten to leave a class in a public forum. Sorry for the unintended insult.

[BMW RACER]

Well, my SIR arrived from Raetech today, looks nice, the hole looks awful small though!

I've got a race coming up on the 26th at Willow Springs. I'll take my 2005 set up with me as well. I'll try them both and report back.

Sure would have been nice if SCCA had done some real homework before making this kneejerk decision. If it turns out to be a bad idea, I doubt they'd be so quick to make any improvements.

[Joe Harlan]

Well, my SIR arrived from Raetech today, looks nice, the hole looks awful small though!

I've got a race coming up on the 26th at Willow Springs. I'll take my 2005 set up with me as well. I'll try them both and report back.

Sure would have been nice if SCCA had done some real homework before making this kneejerk decision. If it turns out to be a bad idea, I doubt they'd be so quick to make any improvements.
[/b]

John, I have a first hand promise that if we can't make it work they will fix it period. Balance is what they are after not killing these cars off. I think Frank will be there with the 300z If I can break away from work I may rip down just to check it out and offer any help i could.

[lateapex911]

Well, my SIR arrived from Raetech today, looks nice, the hole looks awful small though!

I've got a race coming up on the 26th at Willow Springs. I'll take my 2005 set up with me as well. I'll try them both and report back.

Sure would have been nice if SCCA had done some real homework before making this kneejerk decision. If it turns out to be a bad idea, I doubt they'd be so quick to make any improvements.
[/b]

I'm only one voice of the ITAC, but I will say that MY goal is to fix any issues that arise, and my impression, from what our liason with the CRB has said, is that if there are legitimate issues, they will handle them quickly.

I am troubled that Mike thinks it will take him a season to get the item mounted to his satisfaction. But I do encourage him to continue to share information with his fellow racers. I can honestly say that I would be happy to assist any E36 guy, and I think the general nature of racers is such that anyone local would as well.

[Matt Rowe]

I'm only one voice of the ITAC, but I will say that MY goal is to fix any issues that arise, and my impression, from what our liason with the CRB has said, is that if there are legitimate issues, they will handle them quickly.
[/b]

The CRB made the statement in the CRB town hall meeting at the convention that if the SIR sizing i shown to be wrong it will addressed quickly. At least that is what I heard, but there were dozens of other witnesses.

[dj10]

The CRB made the statement in the CRB town hall meeting at the convention that if the SIR sizing i shown to be wrong it will addressed quickly. At least that is what I heard, but there were dozens of other witnesses.
[/b]

I for one am watching how this is playing out VERY CLOSELY! I have another month at least before we can test. I would feel a whole hell of a lot better to see some test results, than to hear theroy from AB and the CRB. No disrespect intended AB or CRB.
dj

[Andy Bettencourt]

I would feel a whole hell of a lot better to see some test results, than to hear theroy from AB and the CRB. No disrespect intended AB or CRB.
dj [/b]

And that position is MORE than reasonable. But...we have to undertsnad that this isn't all theory. This is a technology that has been in use for years by other organizations, and by the SCCA for more than a year. The sizing formula has been developed through actual testing and results. While not on an E36 specifically prior to the ruling, the data has shown that effectiveness does not change by application.

The data and history shows a 27mm SIR will provide 220chp - the only missing link is the application - and that is supposed to be moot.

We have two ITAC guys in the NE who wold love to validate dyno runs/SIR results, should anyone want us there. I doubt it, because it has just as much potential to make more hp than it does less.

AB

[mlytle]

I for one am watching how this is playing out VERY CLOSELY! I have another month at least before we can test. I would feel a whole hell of a lot better to see some test results, than to hear theroy from AB and the CRB. No disrespect intended AB or CRB.
dj
[/b]

for the cost of an sir, all these "easy to find" connection parts and some dyno time, the crb could have just done some basic testing and eliminated most all of the issues that have been thrashed about in these forums and made a bunch of drivers more comfortable. would that have been that hard?

instead, we get...do it, if YOU find problems with OUR solution, tell us and we will fix it. in the mean time, races have gone by and dollars have been wasted.

i ain't saying that an sir is the wrong solution. just saying AGAIN that it isn't fair to make us do mass r&d work on a theory. if scca thinks it will work, then scca should PROVE that it works.

[Joe Harlan]

for the cost of an sir, all these "easy to find" connection parts and some dyno time, the crb could have just done some basic testing and eliminated most all of the issues that have been thrashed about in these forums and made a bunch of drivers more comfortable. would that have been that hard?

instead, we get...do it, if YOU find problems with OUR solution, tell us and we will fix it. in the mean time, races have gone by and dollars have been wasted.

i ain't saying that an sir is the wrong solution. just saying AGAIN that it isn't fair to make us do mass r&d work on a theory. if scca thinks it will work, then scca should PROVE that it works.
[/b]

Who exactly do you guys think the SCCA is? It is you and me and everyone that pays a membership fee. So SCCA (via Dave Finch) did the modeling free of charge to you (The SCCA member) so we (the SCCA Club) didn't spend 50k in the research to help the adhoc (The SCCA ) solve an issue that has be running off other (SCCA) members. I think the SCCA has been doing its homework here and trying not to spend a fortune on this technology. So for anyone to say the SCCA has not worked on this deal is not quite be honest or fair. I believe others are working on dyno information as fast as they can. I have found that Schucks or Kragens stock alot of these silicon boots and adapters in different shapes and colors for those that have them close by.

[mikeblas]

People just need to be a bit more honest when they say the threaten to leave a class in a public forum. Sorry for the unintended insult.
[/b]

You're sorry for the insult, but now you're accusing me of being dishonest?

I'm not sure how all this gets me closer to answers for any of my questions.

Well, my SIR arrived from Raetech today, looks nice, the hole looks awful small though!

I've got a race coming up on the 26th at Willow Springs. I'll take my 2005 set up with me as well. I'll try them both and report back.

Sure would have been nice if SCCA had done some real homework before making this kneejerk decision. If it turns out to be a bad idea, I doubt they'd be so quick to make any improvements.
[/b]

Please do report back as soon as you can, John. I'm particularly interested in learning how you fit the device to your car and I'd love to be able to learn from your experience.

I'm not sure it was a knee-jerk decision, but I'd sure love to learn the details of their testing and study they did themselves before recommending this approach.

I am troubled that Mike thinks it will take him a season to get the item mounted to his satisfaction. But I do encourage him to continue to share information with his fellow racers. I can honestly say that I would be happy to assist any E36 guy, and I think the general nature of racers is such that anyone local would as well.
[/b]

There's only a couple of E36 ITS cars in my region. One guy races very infrequently; the other guy races occasionally, but mostly rents his car out for novice races and driver coaching.

Meanwhile Jake, I never said it would take a season. If it only six weeks, the process has completely devestated my test-and-tune time and my shakedown time. This cascades into the rest of my season, and in a competitive class, I can't afford to loose points or whole races.

Six weeks might sound unreasonably long to you if you run a shop or have a ton of fabrication experience. There's plenty of racers like me, who are using the sport to also become better mechanics. For now, six weeks seems like far too little time.

Thanks for your offer to help. My questions about fitment are in this thread. At the moment, I can't find a commercially available reducer to get from the the thin, plastic flange on my MAF (which is 80mm in diameter) to the 3.0-inch (76mm) exhaust flange on the SIR. That part also needs to be flexible; or have a bend in it, so I can route the SIR doward in the engine bay.

[mlytle]

Who exactly do you guys think the SCCA is? It is you and me and everyone that pays a membership fee. So SCCA (via Dave Finch) did the modeling free of charge to you (The SCCA member) so we (the SCCA Club) didn't spend 50k in the research to help the adhoc (The SCCA ) solve an issue that has be running off other (SCCA) members. I think the SCCA has been doing its homework here and trying not to spend a fortune on this technology. So for anyone to say the SCCA has not worked on this deal is not quite be honest or fair. I believe others are working on dyno information as fast as they can. I have found that Schucks or Kragens stock alot of these silicon boots and adapters in different shapes and colors for those that have them close by.
[/b]

i think the scca is a very large, member run organization that could have very easily spent a grand or two in order to do some basic reality check testing on something for its members before forcing them to do it.

$50k? are you kidding? if you are serious, then it is even worse that the scca has dumped this on a small group of its members.

scca has not fully worked through this deal. volunteer or for profit, the same basic customer service principles apply. i think i am being honest and fair.

you asked.

[BMW RACER]

Thanks for the words of encouragement. At this point I'm going for it and then decide after some track time. I don't think fitment should be too hard. I've found a source for aluminum tubing: www.burnsstainless.com

I'm thinking of getting some 3" tubing in straight and curved sections. Then cutting and welding it kind of like how people fabricate exhaust systems.

Routing wise, I'm thinking 45 deg out of the air mass sensor, down through the hole under the left headlight, kind of like most aftermarket "cold air systems" Then making a right turn that will run in front of the radiator over to the area behind the right fog light. I'll keep you posted on the results.

The hoses shouldn't be too tough I'm thinking 3" tubing, 4mm difference should be workable. Once again I'll get back to you on that.

[dj10]

But...we have to undertsnad that this isn't all theory. This is a technology that has been in use for years by other organizations, and by the SCCA for more than a year. The sizing formula has been developed through actual testing and results. While not on an E36 specifically prior to the ruling, the data has shown that effectiveness does not change by application.

The data and history shows a 27mm SIR will provide 220chp - the only missing link is the application - and that is supposed to be moot.

We have two ITAC guys in the NE who wold love to validate dyno runs/SIR results, should anyone want us there. I doubt it, because it has just as much potential to make more hp than it does less.

AB
[/b]

AB, I ask you, where is the DATA? You keep telling there is data but, where is it? I want to see it and for it to pertain to MY BMW. I want to know if there is any limitations on my rpms & ECU. Are my shift points changing? Is a different geared differential needed?
Lets break down the costs that the CRB want us to absorb.
200.00 for new hose and air filter that will work.
400.00 We all know that this is for the SIR
$$$$.$$ 650 mile round trip to the Dyno & Home (only guy I trust)
$$$.$$ Taking at 2 days off from work.
ALL THIS TO MAKE YOUR CAR GO SLOWER!!!!!!!! PRICELESS!!!!
You add this all up and honestly tell me that the SCCA or CRB shouldn't or couldn't come up with a better plan? Just tell me where the data is for my BMW? Moot to you, not to me and others.
FOR EVERY ACTION THERE IS A EQUAL AND OPPOSITE REACTION
dj

[Andy Bettencourt]

Are you expecting me to have it on my PC? The CRB made a decision based on the data they have.

I told you that the SIR doesn't care what application it is in. Don't know how else to explain it. Your questions can only be answered by you on the track. I suspect you will have minimal issues except a loos of top-end power - should you have more than 220 now. If not, you won't be effected. This is what SIR's do.

If you are concerned about cost, go to a closer one on a Saturday. Nobody is forcing you to spend all that money. How do you know you will go slower? Only if you have more than 220hp. And that would mean your car didn't fit in ITS.

The CRB is testing these this weekend IIRC. If an adjustment in size is needed, IT WILL BE DONE.

What do you think the equal and opposite REACTION is going to be?

I am hoping no adjustment is needed. If it is, it will be.

I am sympathetic to the situation butI believe the CRB acted in good faith.

AB