It's here...

[Fastfred92]

Andy
I think that curb weight can be useful only in that it might shed light into how much stuff you can ditch... If we established spec line weight based only on curb weight minus xxx lbs and used the same amount for all cars ( say 150 lbs ) then that would be a very uniform approach. Who cares if I can only pull out 200 lbs out of my car and I weight 260lbs. Some cars can loose more but if we use the same loss it seems less arbitrary. I think I can get a e36 down to 2500 but it will not do me any good ( legally), and I think the RX7 should be less based on it's curb weight..

 

[Bill Miller]

Jeff and Ron

I still have my 94 325 and directly from the BMW owners manual it has curb weight of 3021 lbs ( 3086 A/T) and list 189 hp @5900 and 181 ftlbs @ 4000. My co workers RX7 (1991) list curb weight 2787 with 160 hp @ 6000 and 140 tq @4000. Maybe the BMW is listed light but for IT specs it is not at all unreasonable to loose 170 lbs, The Mazda only get to loose 107, maybe it should be listed at 2600 lbs. My VR6 GTI SSB car has a listed curb weight of 2830 but runs ITS at 2680 or 150 lbs less... Did anybody explore lowering the Mazda weight ? I think it is reasonable to think that any IT car should weigh 150 lbs ( w/driver ) less than its curb with all the stuff you can junk....
[/b]

Comparing spec weights to curb weights, is about the biggest red herring there is. It's my understanding, that the only time they're even looked at, is to see if it's reasonable to expect that they can get to their spec weight, w/o too much trouble (if at all). Some cars will run under their curb weight, some will run over. At 3150#, that's less than a 5% increase over the curb weight. Hell, even w/ the 100# weight break, the ITB Rabbit GTI still runs ~4% over its curb weight.

 

[Jeremy Billiel]

130 ft-lbs is about all you will see in a full built GSR motor at the wheels. My car is making 125 ft lbs and that is with 4 hours or dyno tuning to fatten up the mid-range.

As far as VTEC goes, you want to get the second lobes to come on as early as possible. If you fall out of this range (tight turn, etc) forget about it. Down shift, rev the piss out of it and hope for the best. the VTEC motors make great hp for the 1.8 L, but tq is the downside. The LS motor (non-VTEC) usually has more tq than the VTEC counterpart.

You are right VTEC doesn't effect RPM, but with the RPM's and big lobes the car can breath to make HP and not tq.

Scott Seck is quite fast, but he would chime in and say the car is heavy and with small brakes it only makes the car harder to manage at the end of runs. A 100 lbs weight reduction woudl put the GSR much closer to the ITS front pack runners IMO, even with the SIR on the BMW's.

 

[Andy Bettencourt]

130 ft-lbs is about all you will see in a full built *** motor at the wheels. My car is making 125 ft lbs and that is with 4 hours or dyno tuning to fatten up the mid-range.
If you fall out of this range (tight turn, etc) forget about it. Down shift, rev the piss out of it and hope for the best. the *** motors make great hp for the ***, but tq is the downside.
[/b]

Edited out specific reference to the HondAcura...just so you know, your post can be interchanged INDENTICALLY with an RX-7.

Peak power is at around 7800, revs can go as high as 9K as long as you have the expensive seals should you want to hold a gear longer - but it ain't making any usable power.

AB

 

[seckerich]

Fred, thank you. That is helpful. Perhaps the real solution was to add 100 lbs to the BMW and take 100 off the Z, the RX7, and others. I could lose 100 lbs on my car easily. Can the others? Steve E., can 100 come off an RX7?
[/b]

Jeff it would be no problem for the RX to loose some weight. I believe we should have been given some weight in the adjustments to make it easier to bring the slower cars up. Give us 50 and reduce the drop in the other cars the same amount. Would give the Z cars a better chance to make weight and still have a safe cage. Not the best option given our low torque numbers, but it would be fair. I always wanted a 60 gallon cooler for my cool suit anyway!! :119: :119:

 

[Andy Bettencourt]

Andy
I think that curb weight can be useful only in that it might shed light into how much stuff you can ditch... If we established spec line weight based only on curb weight minus xxx lbs and used the same amount for all cars ( say 150 lbs ) then that would be a very uniform approach. Who cares if I can only pull out 200 lbs out of my car and I weight 260lbs. Some cars can loose more but if we use the same loss it seems less arbitrary. I think I can get a e36 down to 2500 but it will not do me any good ( legally), and I think the RX7 should be less based on it's curb weight.. [/b]

Fred,

Help me out here. You first sentence I agree with 100%, but from there you lose me.

When does horsepower, suspension design and other intangibles come into play? What complete forula would you like to use?

If you took 150 lbs off of 2 example cars that had the same curb weight - are you saying the minimum weights could be set as easy as that?

 

[Fastfred92]

Fred,

Help me out here. You first sentence I agree with 100%, but from there you lose me.

When does horsepower, suspension design and other intangibles come into play? What complete forula would you like to use?

If you took 150 lbs off of 2 example cars that had the same curb weight - are you saying the minimum weights could be set as easy as that?
[/b]

I think you missed my point or my point was not clear, just saying using a set subtraction ( or addition whatever ) to a OEM curb weight and using that same amount for all cars would be more uniform. From that point you could apply the process and in the end add weight to its base or shed weight for adjustments... I guess that is similar to what is happening now with the exception of the current "black magic" spec line weights.. But who am I, I still want SIR's for all cars so that their max hp is defined and limited.......

 

[Andy Bettencourt]

I think you missed my point or my point was not clear, just saying using a set subtraction ( or addition whatever ) to a OEM curb weight and using that same amount for all cars would be more uniform. From that point you could apply the process and in the end add weight to its base or shed weight for adjustments... I guess that is similar to what is happening now with the exception of the current "black magic" spec line weights.. But who am I, I still want SIR's for all cars so that their max hp is defined and limited.......
[/b]

Maybe I am just missing what is right in front of me. Could you lay out an example or 3 of how this could work with 3 real cars?

 

[Fastfred92]

Maybe I am just missing what is right in front of me. Could you lay out an example or 3 of how this could work with 3 real cars?
[/b]

Just a starting point based off curb weight:
BMW 3021 -150= 2871 189hp x.20 = 226= 12.7
RX7 2780 -150= 2630 160hp x .20= 192= 13.7
VW 2830 -150= 2680 172hp x .20= 206= 13.0
Apply a base weight correction factor to achieve 13/1 so the BMW gets 70 base pounds added, the RX gets to shed 130 and the VW stays the same.
BMW 2940
Mazda 2500
VW 2680
so then a table for adjustments ( made public ) would apply, something like: +50lbs for variable valve timing, + 50 lbs frontal area under XXX or -50 for frontal area over XXX, + 25 for a arm suspension, -50 lbs for torsion bar susp, -50 lbs for SOHC or OHV etc etc.
Thus: BMW gets 50 for vanos, Mazda gets 50 for aero 50 for eng and VW gets to loose 50 for engine architecture and loose 50 for aero
BMW 2990
Mazda 2600
Vw 2580
VW still sucks but it has a black and white method to its madness

 

[lateapex911]

Guys, the problem with chopping 100 pounds (or whatever) off the RX-7 and every car beneath it is that it doesn't end there. Look at the recently published list of adjustments for ITS.

A lot of cars got weight breaks.

I got a personal note from an ITS driver I have never met commenting on a post of mine, who thanked the ITAC for trying to balance the class. He said he thought he could get very close to the new target, and was really happy that we took the approach we chose. Now, if we took the "100 off everybody" approach, two things happen.

1- Some cars lose 100, but all the cars on the adjustment list [/b] lose whatever is listed for them, plus an additional hundred pounds! Just not possible for most cars to acheive that. The guy who wrote me would not see the realignment benefit as he has the potential to now.

2- Now an ENTIRE class is forced to re-engineer their car...a very considerable expense for some in terms of both time and money. Again, it's spreading the issues that are really traceable to ONE car, and loading them to the entire class. Not the fairest solution.

Pragmatically, and from a physical possibilities point of view, this just wouldn't work

A note on curb weights and the idea of a "standard reduction amount". Some cars, and the E36 is a great example of this, are so loaded with extra "stuff", (seat motors, thick insulation) that taking weight off is easy. Others struggle to lose weight once the cage is in.

Curb weight, and real world knowledge are used as checks and balances in the classing process.

 

[stevel]

Edited out specific reference to the HondAcura...just so you know, your post can be interchanged INDENTICALLY with an RX-7.

Peak power is at around 7800, revs can go as high as 9K as long as you have the expensive seals should you want to hold a gear longer - but it ain't making any usable power.

AB
[/b]

Except for the fact that the Mazda is RWD and the Acura is FWD which IS a disadvantage because it's that much more wear on the fronts which is the downfall of this car. And the Mazda has a MUCH better 5th gear, which a FD can't make up for. It's that spacing from 4th to 5th that can really kill the speed. AND, I bet the Mazda has much better weight distribution, which doesn't put as much weight over the front considering how light those rotary engines are and there's no driveline bits behind the front axles of the Acura to shift weight around. So, the fronts on the Acura are just getting abused, if you wanted to make a comparison.

I believe the GSR needs a good 80lb weight break also based on this. AND while we would NEVER use on track performance as an indicator for a change, I think it just SUPPORTS that the Acura just can't hang with the Mazda given all the equality that may exist on paper.

s

Lets see what does Vtec have to do with it? How about the best of both worlds. With prper programming you have the best of both cam curves. You can maximize the torque and yet you still can bring in the extra lift when the HP is needed. Torque is great but some cars are designed to be driven flat out.
[/b]

Joe,

Like has been said here, if you fall off of the high cam lobes, you're screwed. Most people actually LOWER the VTEC crossover point on these cars just to make sure that they don't fall off the high cam, cause if you do you can just watch the 5 guys behind you go right by. For all intents, if you could lock the VTEC pins legally, it would be worth doing.

edit: yeah, the RX7 was pretty damned close to 50/50 which I suspected. The Acura is dealing with 61/39. Oh, and the RX7 has a lower drag Coefficient.

s

 

[Jeremy Billiel]

Except for the fact that the Mazda is RWD and the Acura is FWD which IS a disadvantage because it's that much more wear on the fronts which is the downfall of this car. And the Mazda has a MUCH better 5th gear, which a FD can't make up for. It's that spacing from 4th to 5th that can really kill the speed. AND, I bet the Mazda has much better weight distribution, which doesn't put as much weight over the front considering how light those rotary engines are and there's no driveline bits behind the front axles of the Acura to shift weight around. So, the fronts on the Acura are just getting abused, if you wanted to make a comparison.

I believe the GSR needs a good 80lb weight break also based on this. AND while we would NEVER use on track performance as an indicator for a change, I think it just SUPPORTS that the Acura just can't hang with the Mazda given all the equality that may exist on paper.

s
Joe,

Like has been said here, if you fall off of the high cam lobes, you're screwed. Most people actually LOWER the VTEC crossover point on these cars just to make sure that they don't fall off the high cam, cause if you do you can just watch the 5 guys behind you go right by. For all intents, if you could lock the VTEC pins legally, it would be worth doing.

s
[/b]

Well put Steve! I couldn't have said it better!

 

[Joe Harlan]

Well put Steve! I couldn't have said it better!
[/b]

So let me get this right. This is the 170hp stock engine? Since the Vtec Is ecu controled pinning with software is legal? is it not? The rules allow reprogramming and the Vtec is a function that is ECU controlled? So with all the IT mods this thing has to be making 215 at the flywheel pretty easy. given a 14% loss in the transaxle....185whp. Please don't tell me how bad that FWD car is, I have raced 2 of them many times and those cars rock for a FWD car. While an adjustment may be needed I am not convinced 80 lbs would be in order.

 

[stevel]

So let me get this right. This is the 170hp stock engine? Since the Vtec Is ecu controled pinning with software is legal? is it not? The rules allow reprogramming and the Vtec is a function that is ECU controlled? So with all the IT mods this thing has to be making 215 at the flywheel pretty easy. given a 14% loss in the transaxle....185whp. Please don't tell me how bad that FWD car is, I have raced 2 of them many times and those cars rock for a FWD car. While an adjustment may be needed I am not convinced 80 lbs would be in order.
[/b]

Yes, they do rock for a FWD car. Can they hang with an RX7 at equal weights? I believe it's a big N-O. And yes you can change VTEC activation in the ECU, quite easily. Which is done and that's what Jeremy's car has. The VTEC crossover point is at 4200rpm. If you're below 4200rpm, you're screwed. And the most you'll likely see out of these cars is 180hp to the wheels (on a dynojet) and it doesn't come easy. That's a full tilt, best case scenario IT built motor. And they do handle great, I won't deny that. But the front tires get heated up so much and the front brakes are just abused. They cannot hang with the RX7's for an entire race. They can't. All that weight over the front axles PLUS the FWD just makes the front brakes and tires go away so much that 2/3 thru the race they're toasted. When you've got 2 cars with equal weight, equal power bands, equal brake size, but one has 50/50 weight distribution and is RWD, and the other is 60/40 and FWD, which do you think has the advantage?

s

 

[Joe Harlan]

Yes, they do rock for a FWD car. Can they hang with an RX7 at equal weights? I believe it's a big N-O. And yes you can change VTEC activation in the ECU, quite easily. Which is done and that's what Jeremy's car has. The VTEC crossover point is at 4200rpm. If you're below 4200rpm, you're screwed. And the most you'll likely see out of these cars is 180hp to the wheels (on a dynojet) and it doesn't come easy. That's a full tilt, best case scenario IT built motor. And they do handle great, I won't deny that. But the front tires get heated up so much and the front brakes are just abused. They cannot hang with the RX7's for an entire race. They can't. All that weight over the front axles PLUS the FWD just makes the front brakes and tires go away so much that 2/3 thru the race they're toasted. When you've got 2 cars with equal weight, equal power bands, equal brake size, but one has 50/50 weight distribution and is RWD, and the other is 60/40 and FWD, which do you think has the advantage?

s
[/b]

Well i am not sure how to say it. But that is as close as they are likely to get. That is closer than many combinations all the way through IT. I am pretty confident that that would be a very good race on most tracks. I have the thrill of raing against a couple of these cars and I know how well they handle. I would be shocked of there wasn't more in them.

 

[Andy Bettencourt]

Except for the fact that the Mazda is RWD and the Acura is FWD which IS a disadvantage because it's that much more wear on the fronts which is the downfall of this car. And the Mazda has a MUCH better 5th gear, which a FD can't make up for. It's that spacing from 4th to 5th that can really kill the speed. AND, I bet the Mazda has much better weight distribution, which doesn't put as much weight over the front considering how light those rotary engines are and there's no driveline bits behind the front axles of the Acura to shift weight around. So, the fronts on the Acura are just getting abused, if you wanted to make a comparison.

I believe the GSR needs a good 80lb weight break also based on this. AND while we would NEVER use on track performance as an indicator for a change, I think it just SUPPORTS that the Acura just can't hang with the Mazda given all the equality that may exist on paper.

s


edit: yeah, the RX7 was pretty damned close to 50/50 which I suspected. The Acura is dealing with 61/39. Oh, and the RX7 has a lower drag Coefficient.

s [/b]

I didn't know we were talking about anything but the Integra's supposed lack of torque as compared to the RX-7.

AB

 

[zracre]

Well i am not sure how to say it. But that is as close as they are likely to get. That is closer than many combinations all the way through IT. I am pretty confident that that would be a very good race on most tracks. I have the thrill of raing against a couple of these cars and I know how well they handle. I would be shocked of there wasn't more in them.
[/b]

Joe, Honda does a good job on the VTEC cars for optimising HP...but with the mods allowed, legally, 180 is a real good number. I race a FWD Acura in ITA and If it is run at the level needed to win ITS it would surely go away before the all mighty BMW's and RX7's are caught...you have to rev the crap out of them to get the power...if you dont you are passed instantly.

 

[Joe Harlan]

Joe, Honda does a good job on the VTEC cars for optimising HP...but with the mods allowed, legally, 180 is a real good number. I race a FWD Acura in ITA and If it is run at the level needed to win ITS it would surely go away before the all mighty BMW's and RX7's are caught...you have to rev the crap out of them to get the power...if you dont you are passed instantly.
[/b]

I agree Honda does a good job. I also know there are things that will make them better, they cost money but i think that other 5 HP I mentioned is in there with an expensive header exhaust and maybe a few other IT tricks. I understand the Honda makes its power at high revs and thats the downside to ownign one. But that does not change the fact that they can and if you want to win races you will have to run them that high. The 240z peks out at 7100 RPM and stars breaking the ends off of valve springs at 7300 so you have to rely on torque where we can't run gears to make up for it. It's a toss no matter what you do. I am pretty comforatable saying that with the BMW pulled back the GSR the RX7 and the Z car will be pretty good when you look over 10 different tracks.

 

[zracre]

Time to test the theory...i just won a GSR ssb car on ebay!!


im so stupid sometimes but there it is...the future ITS car

 

[stevel]

I didn't know we were talking about anything but the Integra's supposed lack of torque as compared to the RX-7.

AB
[/b]

Well, keep up! I think my arguments are a good case for why the Acura should get a weight break.

s