SIR Discussion

[RussMcB]

This topic was created so we wouldn't need to continue highjacking another thread.

I like the SIR from the point of view that it will greatly reduce the HP deficit for someone who chooses to run a stock, unopened engine.

With the SIR, front runners will still spend the same amount of their expendable dollars to have the highest HP they can afford, but they may be 10-15 HP more than me rather than 20-40.

Yes, that's a selfish view, but I don't have much sympathy for people who spend many tens of thousands of dollars for engine development for amatuer club racing.

I realize that the SIR would require extra mounting, but I can do that on the cheap in the scheme of things.

I admit that I do not know how much an SIR itself costs. Maybe SCCA will provide them for free at each races to discourage tampering. :-).

on edit: SIR might keep my 2005 engine more competitive for more years. I didn't build my car thinking I'd need to reengineer engine mounts every few years. An SIR would mean I'd be fewer seconds off the pace of the fastest spenders, I mean, drivers.

[Wren]

as someone with good access to engineering software, an engineering background, lots of free time, and a cnc lathe, I'm all for it. I'm not even sure what kind of crazy venturis I'd end up with, but it is just another place for people to spend money.

Seriously, the reserach literature on the subject shows not much difference between different restrictors and intake designs on 600cc bike motor engines for FSAE. Most of the difference is in the tuning and I do see this as a great place for people to blow a lot of money on chassis dyno time.

What would be the logistics of requiring sealed motors and having the different engine builders seal them?

[RobLav]

You guys already know my position against the SIR here (not always popular btw - lol)

But I will leave the class in a heartbeat if we have sealed engines. At one point in our rulemaking process, I had agreed to a SIR if it limited it to about 175HP - no less.

But like I mentioned on the other post, if we do restrictors, we need to allow for two. Hopefully, this will never happen.

[Brands]

I'm with Rob I'm afraid! I've never liked the SIR idea and using it on a bike motor makes no sense to me. I'm already a few bhp down on a 07 GSXR so I'll just have to brake later!
Ben

[carnut169]

I like the SIR. It needs to be at about 185 so the best, legal motors are not restricted but anyone running cheater parts can't take advantage of it. I'd like to know that my competitors are straight-up, and for them to know I am.

It also needs to be sourced from a single supplier so there is no hanky panky.

[RobLav]

All the usual suspects reply!

I might could go with 185HP... but still think we need dual inlets.

Good Luck at the ARRC.

[RussMcB]

As racers, we all want the most HP we can get. However if everyone has 175 HP then it's more of a driver's class and parts are less stressed. You know what that means? You can do more racing for the same amount of money and that racing is going to be more competitive and fun. The best drivers/engineers have a better chance to compete against people spending more money.

[Stan Clayton]

Without taking sides in this issue I have a few data points for you to consider.

First, a motorcycle engine has to be able to make at least 112% (at the countershaft) of the SIR target power for the same engine to deliver the target hp with an SIR. For a 185 hp SIR, that means that the very same engine has to be able to make 185 x 1.12 = 207 hp without an SIR to make 185 with one. That sounds like DSR prep level to me.

BTW, that's why the GSXR that Arnie Loyning ran on the dyno last year made only 140 hp at the countershaft. According to Sportrider Magazine, it made 162 at the rear tire. Account for SIR and chain losses and it sounds pretty close to me.

Second, IIRC the argument last year was whether to permit DSR engine prep and require an SIR, or to stick with stock internals to keep the cost down. At the time there was strong support for forgoing the SIR and its associated costs.

Finally, we have been using SIRs from a number of suppliers for several years in other classes, and policing them -- avoiding any hanky-panky -- has been a snap. Measure the diameter, then unplug the MAP sensor and administer the tennis ball check. Piece of cake...and no need to spec a sole-source.

Stan

[Billy Wight]

There are ways to cheat a SIR as well... If someone really wants to cheat, they can always find a way. It just might be a little more difficult with the SIR.

I personally like the idea of a SIR; it allows the older engines to have a chance against the latest and greatest and in some cases even makes them more competitive than a newer high revving engine. An older engine with a smaller bore and longer stroke (and lower revving) than the newer engines typically produces more torque with less horsepower at lower RPM's. The SIR will essentially limit the RPM levels of all the engines, but since the older engines make their torque and power at lower RPM's they will be less effected.

[carnut169]

First, a motorcycle engine has to be able to make at least 112% (at the countershaft) of the SIR target power for the same engine to deliver the target hp with an SIR. For a 185 hp SIR, that means that the very same engine has to be able to make 185 x 1.12 = 207 hp without an SIR to make 185 with one. That sounds like DSR prep level to me.

Stan

Wow. I had no idea it had that effect on the motor. No, I don't want my 185hp engine choked down to 165hp. How does it effect torque?

[stonebridge20]

You guys want to open a VERY large can of worms with SIR's ? Go over to the GT site and do a search on SIR's. You can find EVERYTHING you ever wanted to know there about SIR's ! http://www.gt-racecar.com/forums/default.asp I do know one thing about them,...You buy them from www.raetechmotorsports.com for BIG money if you want HP. Or you try one of the many others that DO NOT make the same HP. Then there's the tricks that you do with it (which I know) to "make it work". SIR's,...It's one of the reasons I sold my GT3 car and came back to F/F !

Have fun, Mike

[Brandon Dixon]

I really hope that we do NOT go to a SIR. I like the fact that we are buying awsome engines for low cost. The engine managment systems on these things are very sophisticated and it's clearly part of the reson that they work so well and remain so driveable. A SIR is likely to screw all of that up. I don't want to spend a bunch of time and money redoing the engine management because it now is breathing through a restrictor.

[George Dean]

Hi Guys, Have I missed somthing here? I thought we were supposed to have a rule in place that required us to use OEM components only. Russ states that someone with enough money spent will have 20-40 more horsepower than him unless a SIR is in place then it will be more like 15 -20. On my best day I can not make 20- 40 more horsepower using OEM parts. Every one of the engines that has come through my shop that I have tested for formula 1000 this includes 05-06-07 GSXR1000 engines has been within 5 horsepower of the stock motorcycles I have tested of the same year. I have played with restrictors on some mini sprint engines this last year. Believe me you dont want to go there. The cost of your engine program if you want the cutting edge of restricted engines just went up.

George

[RussMcB]

Thanks, George. Your view points carry plenty of weight. I'm glad to hear that there aren't a lot of gains to be had from race prepped engines over stock engines (I'm assuming both are same manufacturer and year).

I might be happy with no SIR depending on your answer to this question.

(Assumption: Each year motorcycles will continue to gain HP.)

If I do all the relatively easy mods to my 2005 Kawasaki engine, such as decent exhaust, Power Commander, TRE, & air box (am I leaving anything out?), what can I expect to see for a gap between my bottom-of-the-price-range engine compared to the current year's engine with all your typical mods? Is it going to grow each year so that the choice is either fall further behind or get newer model engines every so often?

Of course, I don't expect to run with someone spending a lot more money than me, but at the same time, wouldn't everyone (except the very rich) benefit from something that can stabilize HP and not require chassis changes to match physical changes to newer engines?

As a comparison, can you think of any other classes where you need to discard your engine for a newer better model regularly?

[Wren]

As a comparison, can you think of any other classes where you need to discard your engine for a newer better model regularly?

the last rebuild of my vee engine cost $2500 and the builder gave me a cam for free after it wiped two lobes on the dyno. That engine might go 10 weekends if I baby it, or it might put a rod through the block if I screw up at all and cost me $5000 for a new one.

I can get two '07 GSXR 1000 motors for $2500(if I try hard enough), they will be relatively trouble free, EFI engines that will last longer than 10 weekends.

[Brands]

I know I've mentioned this before but when I was racing back in the UK in the Formula Honda Championship we had a year cap on the motors (at the time nothing newer than the 'FW' motor) and several regulated positions for wire seals. If a motor was protested then it could be sealed and inspected at a later date. I worked fine and this was in a national championship. Of course one guy did a motor swap between qualifying and the race and 'accidentally' fitted a 900cc motor when we where all running 600's!

On another note it looks like I may have to pull out of the ARRC much to my dismay. Engine wiring issues being the primary reason.

Ben

[RussMcB]

I can get two '07 GSXR 1000 motors for $2500(if I try hard enough), they will be relatively trouble free, EFI engines that will last longer than 10 weekends.

Yep, and you'll be sitting pretty for, what one or two years? Then what are your options? If the 2008 & 2009 engines make more HP and you want to compete with people who have them, your two options will be to live with it and be unhappy that you're down on power or sell your 2007 engines (to whom?), modify your chassis, buy one or two more 2009 engines and make whatever changes needed to make them fit and perform.

What I'm hoping for is something that keeps 2+ year old engines in the hunt.

[George Dean]

Russ, I guess I still dont understand what you are saying about the guys that spend the most money getting the most horsepower from their engines. The rules as they were told to me were that all engine internals were to remain stock. The clutch could be modified and the oil system could be modified. Compression ratio must remain stock. I live by these rules. So when a brand new motor comes to my shop the customer usually asks for a clutch basket and maybe a oil pump mod. Mostly the motor gets put on my dyno and run for about 45 minutes to 1 hour for breakin. During this time I am monitoring all tempretures and pressures, as well as changing throttle positions. The engines that come to my shop that have been run I do take apart and put new bearings in and do a valve adjustment. Before putting them through the same dyno treatment. Then after all of the heat cycles and it cools down I bring it up to tempreture once more to do some dyno pulls and reflash the ECU (on Suzukis). Then the motor is shipped. I have not seen a difference between the engines that I have put new bearings in and the brand new engines. The only cost difference is the bearings and labor for the engine freshen. A DSR engine is a completely different story! I still think we have the most cost effective form of racing.
Yes buying a new motor every year as the new ones come out to keep up with the most power output may be in the cards for some but I dont know if you really have to. I have almost 14,000 dyno pulls in my computer now and here are some numbers you can crunch on: 04 GSXR1000 with pipe and good airbox 167hp 83ft lbs
05-06 GSXR1000 with pipe and airbox 173hp 85ft lbs
07 GSXR1000 with pipe and airbox 181hp 85ft lbs
05 ZX10 with good pipe and airbox 171hp 84ft lbs
07 ZX10 IMSA spec pipe and airbox 176hp 85ft lbs
07 R1 motorcycle graves pipe PC 176hp 84ft lbs

I hope this answers some of your questions I am here to help

George

[George Dean]

Ben, If I were to get you a wire harness would you be able to run?

George

[VehDyn]

George's numbers are at the wheel, by the way. I am a George Dean customer and am very happy. He does great work, is a straight shooter, and always available to answer a question. For me, its a no brainer to be a return customer for him.

Ken Tandy

[Purple Frog]

I really like what George is saying. I see the point about the costs of engineering around an SIR building cost.

If we don't go with a SIR or equivalent, then I suppose we just go on the "honor" system until it is perceived to be failing. I know from experience that unless the the circumstances are extreme, formula car racers don't protest other's motors. I haven't heard about one in the last ten years (maybe Clayton has statistics?) There might be a lot of grumbling, but rarely a protest. If the grumbling builds into a perception, it could hurt the growth of the class.

And suppose there was a protest. Who's the independent judge and how does the motor get there if no provisions are made for seals? Don't expect SCCA to have inspectors at national races that know a stock R1 rod from a trick one. Just thoughts for next summer...

I love the class. But, I know it's doomed if there becomes a DSR-like engine war, or even a perception of one.


hum...maybe a old-fashioned claimer rule...

[Wren]

Yep, and you'll be sitting pretty for, what one or two years? Then what are your options? If the 2008 & 2009 engines make more HP and you want to compete with people who have them, your two options will be to live with it and be unhappy that you're down on power or sell your 2007 engines (to whom?), modify your chassis, buy one or two more 2009 engines and make whatever changes needed to make them fit and perform.

What I'm hoping for is something that keeps 2+ year old engines in the hunt.

but I'll still be in for less money than the rebuilds on a vee engine, I don't even know what guys are paying for pinto/kent rebuilds, but I bet it's a lot more than $2500.

If you go back through the archive you'll see where Lee Stohr talks about putting in junkyard motors and going faster than built Loyning's motors.

With an SIR, it will still be a matter of buying the latest engine, it just means we'll spend more time in front of a flowbench and building different SIR's to test.

[RussMcB]

It's encouraging that people are thinking that our "stock internals" rule is sufficient to keep engines relatively equal. That will be great if true.

I'm extremely grateful that we do not DSR engine rules. I wouldn't be in the class if that were the case.

Regarding our F1000 costs vs something like FV. I agree we kick butt, and that was a big draw for me to F1000. However, it doesn't really matter what our costs are compared to other classes once you're in. Now I only care about my costs vs. other FB competitors. In other words, I want relatively low costs for all F1000 owners. That will help me enjoy the class with the financial level I can afford.

George, my gripe is less with someone spending money to optimize their engine than it is with someone spending money to buy the next year's engine because it makes more base HP. Then the goal posts keep moving further away each year. In other formula classes you generally don't have to worry about constant improvements being readily available and legal every year. Imagine something like that happening in FE.

I guess we can simply hope that 1 liter engines hit their own ceiling.

George, (sidebar), if you can help Brands (aka Ben) get his engine running in time for the ARRC, that would be fantastic. He (like many of us) has been working hard to make this race. It would be a shame after all of the planning. His mum flew over from England to see him debut his new car!

[Sean Maisey]

George,

Thanks for the data on recent engines. You recently mentioned that one of the key differences in the horsepower 'increases' at least for the GSXRs is that the newer engines rev higher, increasing the torque multiplier. This implies that the peak torque is more telling for relative performance, and these numbers are remarkably similar.

Can you supply peak torque/HP rpms for these examples?

Sean

P.S. Ben, Take George up on his offer. Bring your car, and we'll all pitch in to get it running if necessary.

[RobLav]

I agree with Sean M. That's the first thing I noticed about George's numbers - the similarities in torque.

But I'd say that it is way too soon anyway to decide on SIR or not. And one good race (ARRC) is not enough to make that decision. We need at least another year (maybe two). I'm sure it'll be a hot topic at the Runoffs if we get there in 2009.

[RussMcB]

Good discussion. Good points being raised.

I need to be reminded about the difference between HP & torque in practical terms. If the following two similar cars pull out of a slow corner together onto a long straight (like Rd Atl T7 - T10a), will the newer engine reach a higher top speed and arrive at the braking zone noticeably earlier?

07 GSXR1000 with pipe and airbox 181hp 85ft lbs
05 ZX10 with good pipe and airbox 171hp 84ft lbs

In other words, is 10 extra HP going to allow the newer engine to gradually pull away or is the torque even enough so they'll stay side by side?

[Brandon Dixon]

Good discussion. Good points being raised.

I need to be reminded about the difference between HP & torque in practical terms. If the following two similar cars pull out of a slow corner together onto a long straight (like Rd Atl T7 - T10a), will the newer engine reach a higher top speed and arrive at the braking zone noticeably earlier?

07 GSXR1000 with pipe and airbox 181hp 85ft lbs
05 ZX10 with good pipe and airbox 171hp 84ft lbs

In other words, is 10 extra HP going to allow the newer engine to gradually pull away or is the torque even enough so they'll stay side by side?

I think that there are more important things than which of the two engines above that you have. These cars have very impressive power to weight ratios, so putting all the power down from either engine coming off the corner will be a challenge. I think that driver skill and car setup will dictate who gets off the corner best.

At the far end of the straight the aerodynamic configuration of the cars is going to make more difference. Some of these cars are set up for big downforce with the associated high speed drag. Some are converted FC cars where the downforce and drag levels are lower, some are in between. These are going to be very interesting tradeoffs to compare.

[RussMcB]

I should have stated identical cars/drivers skill/set up/conditions. And maybe replace the T7 - T10a scenario with a rolling start from 50 MPH for a distance of 1/2 mile. What will be the difference between those two engines at the end of the 1/2 mile? Inches? Feet? Car lengths?

[stonebridge20]

I think FEET. Because the guy with the 05ZX10 will tuck behind the guy with the 07 GSXR and catch a draft. He will then pull out just before the 1/2 mile marker and they will cross the line ALMOST side by side!

Seriously,..You would need to see dyno sheets and where these two engines make their peak HP and Tq and how long those "curves" are. If both engines were on a SIR,...The engine with the most Tq below the "curve" prior to the SIR going sonic would be the "winner".

Usual disclaimers apply.

[Eric Cruz]

Hi Russ,
Power is the RATE of making torque. Here's the relationship:

Power (hp) = Torque (ft-lb) * RPM / 5252

That's why power and torque curves for a given motor, plotted on the same graph, will always cross at 5252 RPM (except things like my Duramax Diesel that never even rev that high...).

Anyway, a practical way to look at this relationship is what you are after, not another equation. Remember that it is the torque at the rear wheels that accelerates the car. Let's assume that both cars get the same launch out of 7 as limited by traction. Once you get into higher gears (and more speed/downforce) breaking the rear loose will not be an issue. Acceleration down the straight will be a function of how much torque can be delivered to the rear wheels.

You can make all the torque you want at the rear wheels with gears. But the lower you gear it the sooner you run out of revs. (You can drive a Sherman Tank up Pikes Peak with an electric razor motor and enough gearing, you just won't do it very quickly...somebody famous said something like that.)

If the two motors in question make the same torque, but one makes more power, then it is making that torque at a higher rpm. (Oversimplified, but we don't have the curves in front of us...) So a way to think of it is with the more powerful motor, you could run shorter gearing (bigger sprocket in the back), develop more torque at the wheel, and accelerate quicker than the car with the other motor, up to the same car speed.

Or you could run the same gearing and perhaps reach a higher top end. It depends on a lot of things, like aero drag, power to weight, length of the straight etc., but you should always be able to optimize the car with more power to go quicker than the one with less.


See you at RA in a couple of days.

Best regards,
Eric

[Daryl DeArman]

Perhaps it is time to revisit the suggestion of motor eligibility dates.

For example for 2008-2012 seasons all motor years 2008 and older. That will give the class at least 5 years of growth with increasing availibility of used motors without having to worry about the 09-12 model year 'motors to have'. Have a little bit of stability while the class gets off the ground.

In 2012 discuss whether it is desirable to keep the concept and change the rule to 2013-2017 all motors 2013 or older.

I've been there, for a short time and done that. I don't think you want to have to upgrade motors as quickly as the factories improve these things. Some of the horsepower deltas are being downplayed because a)the class is trying to grow and b)there are enough other variables right now that the HP isn't going to make that much difference. However, in short order the pointy end will be killing for the extra 5-10HP. Don't think so? look at FF, FC, and FV tell me how much money is being spent for an extra couple of horsepower in those classes and then tell me that same kind of effort isn't going to be spent on an extra 10!

[RussMcB]

Thanks, Eric. Good explanation.

Daryl, I like that idea. It seems like it would accomplish the goal of avoiding frequent engine upgrades and keeping the field more even (better competition).

Any down sides?

[Purple Frog]

Locking into an engine year for a 5 year period sounds like a bad thing for F1000. The class has a foundation based on wizzy new bike motors. And, more importantly availability of low cost from wrecks. Stay current, stay sexy.
Five years seems like a long long time to a 20 year old.

How many of you own 5 year old laptops?

[Stan Clayton]

How many of you own 5 year old laptops?

Hand goes up...

[RussMcB]

Locking into an engine year for a 5 year period sounds like a bad thing for F1000. The class has a foundation based on wizzy new bike motors. And, more importantly availability of low cost from wrecks. Stay current, stay sexy.
Five years seems like a long long time to a 20 year old.

How many of you own 5 year old laptops?

Laptops are appliances. They're not often in competition. That's like saying how old is your refrigerator.

Would you feel the same about the attractiveness of the latest wizzy thing if you had an F1000 car and engine sitting in your garage wondering what you're going to need to do each year or two to keep it competitive?

I think it's pretty safe to say that motorcycle manufacturers have little incentive to keep engine physical characteristics the same each year. That means chassis modifications every time you want to stay wizzy current.

[Daryl DeArman]

Locking into an engine year for a 5 year period sounds like a bad thing for F1000. The class has a foundation based on wizzy new bike motors. And, more importantly availability of low cost from wrecks. Stay current, stay sexy.
Five years seems like a long long time to a 20 year old.

I am not a F1000 owner so I shouldn't have any say on whether it is a bad thing or not. I do know that the HP and technology with bike motors is a constant evolution. Changing motors every year or two is probably worse for the class than some sort of enforced stability.

I am pretty confident that 5 years from now someone isn't going to look at a 12,000 rpm FI motor with variable intake runner length, traction control and variable cam timing as too old school. And if they do, the very next season they can upgrade the old lump for a 2013 model.

[racer27]

I think some guys, myself included, are looking at F1000, as a lower maintaince alternative to running a Pinto FC.

I am hoping the F1000 class is one where routine maintance on the powerplant is less then the maintiance with the Pinto.
I was told by an FB Owner @ Summitt, that his F1000 (Powerplant wise) was for most part gas and go. He was dealing with carburation/ign issues on his Pinto FC that weekend.

I'm hoping with F1000 to be able to keep the engine in the back of the car until it breaks.

[cparsons]

Leave restrictor plate racing to Nascar, no SIR in FB please.
The hp and torque of the major Japanese manufacturers, for a given year, are very close. Susuki has had a slight edge for a few years but never more than 10 hp between the strongest and the weakest motor for a given year. Pactically NO difference in torque, a ft. lb. or 2. There were dyno charts posted on a previous thread a few months back that proved this. The motors have gotten stronger through the years, but they ALL have gotten stronger. The "big 4" Japanese manufacturers have agreed to a 186hp cap to put an end to the hp war. However, Aprilia has a v4 1kcc 200+ hp that is rumored to be released in 2008. Honda also has a v4 1kcc in development. We don't need to worry about cheaters. The guys with the deep pockets just need to buy a stock 08 Aprilia or Honda v4 and dust all of us runing inline 4's.

[RussMcB]

Funny title to your post. I almost missed that. :-).

When you say that ALL have gotten stronger, that's true, but I don't think that's a good thing if it means engines constantly become more uncompetitive each year that passes.

However, I'm glad you pointed out the 186 HP agreement. That's encouraging. If true, that would be great for giving engines a better chance to stay competitive longer.

[jerry freeman]

I don't like the SIR rule. If you want to limit the year model I think that would be better. you could limit the motors for 2-3 years and then up the years 2-3 years at the end of the last restriction. Policing the SIR is just another pain and added expense. No matter what you do the guys with money will always be able to buy more motors, freshen them up, dyno them, and pick the best one. you can't beat money in any kind of racing. Period. I don't like it any more than anyone else since I have probably the smallest budget out there, but I know how the system works. And, on the subject of sealed motors, I will go to formula super before I race any class with sealed motors that you have to send to somebody to pay to seal. Just my oppion.

Jerry