Newest MW/GL GTS2 build

[scottbm3]

shoo-shiddily-diddily, Trevor. That's the hardest I've laughed at a post in a long time!

 

I'm 230, so I'm shooting for a wt of the car to be around 2900--real easy to do and costs $0. I expect I'll be way under that and have to ballast up.

 

For the experts (and Scott ), what would be a reasonably competitive competition wt on a GTS3 car with stock power (okay, I've got underdrive pullies and a ltw fly)?

 

Kyle,

 

I'm definetly not an expert, but if your car is basically stock you'll probablly be around 210 whp. That would allow you to get down to 2365 lbs(not realistic) Do you still have your heater core, sunroof, sound deadening material on the floorboard etc. You'll fnd that without a lot of mods your car will be heavy. Probably around 2900-3000 lbs.w/driver maybe more being your size. The curb weight from the factory was 3175. That would put you very close to the mininum high side number for wt/hp(14.49 for GTS3). You can add some weight and fall into GTS2. Being competetive is a another topic completely. Best of luck with your build and look forward to seeing you out there running in GTS whichever class you choose. The more the better.

 

Cheers, Scott B.

[cosm3os]

Thanks, Scott. I guess I'm just bench building at this point; holding my pecker till I get it on the scales and dyno.

[cstreit911]

Not that this is news to anyone, I always vote for lighter vs. more HP. Easier on all the components. However at faster tracks the HP does have an advantage (RA for example). My car weighs in 2280# with me and a few gallons of gas and 40# of ballast (2025# dry). I used 50% of one set of brake pads this season. (4 axles, 3 transmissions, and 2 splitters lol)

 

You bimmer guys chap my @#%$ though. 3000# cars that still seem to handle better than my 911.

 

It'll be great to see another new car out in the MW this year!

[JSG1901]

Thanks, Scott. I guess I'm just bench building at this point; holding my pecker till I get it on the scales and dyno.

Wow...your pecker is so big you need to weigh it? I'm impressed. Definitely a GTS3 guy.

[cosm3os]

Thanks, Scott. I guess I'm just bench building at this point; holding my pecker till I get it on the scales and dyno.

Wow...your pecker is so big you need to weigh it? I'm impressed. Definitely a GTS3 guy.

 

Yep. Need a all wheel dyno to handle it, too!

[ELEPHANT1]

Most other things being equal one thing to consider is whether or not they'll be running mostly at tracks where the lighter cars will handle that much better through the corners than the heavier cars. Of course there are many factors here too...level of suspension and set up (as Wonger mentioned), tires.....

 

I too am in the camp of lighter rather than higher HP but that's because I'm not willing to put much $$$ or effort yet into making the motor more powerful. Right now it's stock, legal in every way for any stock class that might exist. I do plan on adding a few things which will make it absolutely not stock class legal (or IT or prepared for that matter) but I don't expect much HP gain, it's more in the name of weight.

 

I'm already getting pretty excited for GTS2 next year!

[jvanhouten]

I too prefer the lighter car over the heavier car and I do think there is a advantage, to a point. Once you get to too large a power deficit however, you just get crushed down the straights.

 

Case and point, Nationals this year. Since my E30 M3 wasn't going to be done in time, we took a Spec E30 car, put a good suspension on it (AST 4300s) with slicks, better brakes and dropped some weight to fit into GTS/2. It ended up with an average HP/TQ of ~157 and a target weight of ~2500 lbs. Based on a quick look at the windshield tags, most cars were 400+lbs heavier and with the "better" DOT-R ratio, much more power.

 

In the rain on Friday when power doesn't matter as much, I was very competitive, finishing 3rd in class/15th overall (2nd/14th after a DQ), <5 sec off Scott in 1st. That was very encouraging and we thought that we made the right call on going light weight/low power. However, as track dried and the weekend played out, it became clear that I had just too little power. No matter how much I gained in the turns it was more than offset by the loss down the straights.

 

Now the car wasn't fully optimized (~90lbs overweight, suspension needs some more dialing in, driver needs more seat time ), but it was pretty clear--even though I would gain in the corners, I had way to little power to even draft down the straights. It was frustrating to leave the keyhole with a couple of lengths and better exit speed to have 10+ lengths pulled by the trailing car into brake zone at 7. Now the fact that the E30 is an aero brick doesn't help, but it became pretty clear that you need to at least be "in the ballpark" on power to be competitive. Some of it is the "worse" ratio of the slicks, for sure, but still, it was dramatic.

 

Anyway, that's my experience. I had an absolute blast and will be back next year for sure. I'm still building the E30 M3 and it is being built to be light, but I'm now reconsidering what motor to put in the car--I've got a BMW V8 that's sitting around--humm...

 

John

[Hornswoggler]

One other idea to consider is the possibility of PTD or PTA. In kicking around the idea of GTS3 next year, I think it can be a good PTA car as well. Sounds like your GTS2 build could stay PTD. Even if ya slip to PTC, I bet you could still be competitive.

[JSG1901]

John,

 

That's a really interesting example. I would love to know how competitive you'd have been if you could have got down to the DOT-tire minimum weight of 2,276. Last year at Nationals I was on slicks, too (my car was too heavy by 250lbs or so) and I didn't think they made up enough. This year, on DOTs but with the car's weight running near the minmum, I'm quite competitive.

 

Interesting dilemma. Add in, as you said, the aero differences...hard to know.

[jvanhouten]

Scott-

 

I hear you--given that this was/is a Spec E30 car (once I undo all the GTS changes), we were limited in what we could do. Given the weight and power of the car going in, GTS/2 on slicks was the best option in that 1. I could dial in the weight without doing too much and/or making irreversible changes that would make it illegal for Spec E30, 2. I wasn't going to open up the engine to put in a cam, etc. so it only had a few bolt-ons, 3. I had the right sized slicks sitting around Going any lighter than ~2370 lbs the car weighs now will require lexan/CF/FG panels, stripped wiring harness, etc. and that was just too much $/work for a car that will be Spec E30 again shortly. Now, the E30 M3's target weight is <2100 lbs, so we'll see...

 

I think at the lower classes (GTS/1,2 maybe 3) the spread for slicks is to great to be overcome at Mid-Ohio--Grattan might be a different story Once I figure out what motor I'm going to go with, unless it's big power (GTS4/5) I'm going to target DOT-R weight.

 

All that being said, there was at least another second in setup/driver available and given the car was put together <3 weeks before Nationals, I was pretty happy with how it turned out. However, none of that second would have been down the straight At a minimum, we learned a lot for next year, so look out!

Edited September 26, 2008 by Guest

[cosm3os]

Colin:

 

Although the rest of the car will remain unchanged, the cage to the rear strut towers will bump me to TTC. That being said, I don't think the PT classes get a whole lot of action around here (certaninlynot as much as GTS).

[ELEPHANT1]

Hey that reminds me of a question about ballast that I'm unclear on. Perhaps if I reread it a few times it would become more clear but maybe it's already clear to everyone else.

 

How much ballast can we add within the rules? I recall it's 100lbs (probably not including a spare wheel/tire) but do the GTS rules supercede that and we can run what we need to run?

 

I'm curious because with the one engine mod I'm doing it's going to add some power and as it was my car was going to be pretty darn close on weight. I don't want to be in a position of needing to add 200lbs of ballast and not having a rules compliant way to do it.

 

Cheers.

[bmw22]

One other idea to consider is the possibility of PTD or PTA. In kicking around the idea of GTS3 next year, I think it can be a good PTA car as well. Sounds like your GTS2 build could stay PTD. Even if ya slip to PTC, I bet you could still be competitive.

 

 

Eric Wong finished 3rd in GTS3 and 2nd in PTA with his M3

[JSG1901]

I know of at least one GTS car that ran well over 200lbs of ballast, FWIW. I don't know of any limitations (but I might not know what I'm talking about).

[ELEPHANT1]

I know of at least one GTS car that ran well over 200lbs of ballast, FWIW. I don't know of any limitations (but I might not know what I'm talking about).

 

Yeah, I'll reread it over and over and see if I can understand it. Admittedly I probably didn't spend enough time reading it. My bad.

[scottbm3]

I know of at least one GTS car that ran well over 200lbs of ballast, FWIW. I don't know of any limitations (but I might not know what I'm talking about).

 

Yeah, I'll reread it over and over and see if I can understand it. Admittedly I probably didn't spend enough time reading it. My bad.

 

See, and you thought it was so easy to interpert the rules from BMWCR..... J/K

 

 

-Scott B.

[ELEPHANT1]

I know of at least one GTS car that ran well over 200lbs of ballast, FWIW. I don't know of any limitations (but I might not know what I'm talking about).

 

Yeah, I'll reread it over and over and see if I can understand it. Admittedly I probably didn't spend enough time reading it. My bad.

 

See, and you thought it was so easy to interpert the rules from BMWCR..... J/K

 

 

-Scott B.

 

Well sure, that's easy when you cowrite them. ; )

 

Actually I searched the entire CCR and could not even find the term 'ballast'. I also searched weight, lead, lbs.,pound....nothing related to ballast came up. I'll keep looking though, there has to be something in there about it. Unless of course they leave that up to specific class/series rules which may be the case.

 

Cheers.

[Damon in STL]

Case and point, Nationals this year. Since my E30 M3 wasn't going to be done in time, we took a Spec E30 car, put a good suspension on it (AST 4300s) with slicks, better brakes and dropped some weight to fit into GTS/2. It ended up with an average HP/TQ of ~157 and a target weight of ~2500 lbs. Based on a quick look at the windshield tags, most cars were 400+lbs heavier and with the "better" DOT-R ratio, much more power.

 

 

I'm curious about what you are referring to when you say "with the "better" DOT-R ratio" above?

 

I've decided to move back to the Hankook DOT-Rs from the F200 slicks since there are no more to be had for $100 a pop! And, I wasn't able to reduce camber (in the rear) to really make use of the slicks anyway. I've got right at 300 lbs. I can loose by making the switch.

 

Where I'm hoping there can be some time made up is under braking with the lighter weight and also higher corner exit speed.

 

Damon in STL

[ELEPHANT1]

Case and point, Nationals this year. Since my E30 M3 wasn't going to be done in time, we took a Spec E30 car, put a good suspension on it (AST 4300s) with slicks, better brakes and dropped some weight to fit into GTS/2. It ended up with an average HP/TQ of ~157 and a target weight of ~2500 lbs. Based on a quick look at the windshield tags, most cars were 400+lbs heavier and with the "better" DOT-R ratio, much more power.

 

 

I'm curious about what you are referring to when you say "with the "better" DOT-R ratio" above?

 

I've decided to move back to the Hankook DOT-Rs from the F200 slicks since there are no more to be had for $100 a pop! And, I wasn't able to reduce camber (in the rear) to really make use of the slicks anyway. I've got right at 300 lbs. I can loose by making the switch.

 

Where I'm hoping there can be some time made up is under braking with the lighter weight and also higher corner exit speed.

 

Damon in STL

 

My suspicion is maybe Hoosiers given that they offer a decent contingency now. We actually have a few good sources for Hoosiers so it's not so much more expensive for us to run them as it was years ago. I'm interested in the BFG's but with no contingency I don't see it. Hankook is still a decent looking choice but gotta do some testing.

 

Cheers.

[scottbm3]

Case and point, Nationals this year. Since my E30 M3 wasn't going to be done in time, we took a Spec E30 car, put a good suspension on it (AST 4300s) with slicks, better brakes and dropped some weight to fit into GTS/2. It ended up with an average HP/TQ of ~157 and a target weight of ~2500 lbs. Based on a quick look at the windshield tags, most cars were 400+lbs heavier and with the "better" DOT-R ratio, much more power.

 

 

I'm curious about what you are referring to when you say "with the "better" DOT-R ratio" above?

 

I've decided to move back to the Hankook DOT-Rs from the F200 slicks since there are no more to be had for $100 a pop! And, I wasn't able to reduce camber (in the rear) to really make use of the slicks anyway. I've got right at 300 lbs. I can loose by making the switch.

 

 

 

 

Where I'm hoping there can be some time made up is under braking with the lighter weight and also higher corner exit speed.

 

Damon in STL

 

My suspicion is maybe Hoosiers given that they offer a decent contingency now. We actually have a few good sources for Hoosiers so it's not so much more expensive for us to run them as it was years ago. I'm interested in the BFG's but with no contingency I don't see it. Hankook is still a decent looking choice but gotta do some testing.

 

Cheers.

 

I've heard from guys running the BFG's that they are pretty good to start but fall off pretty bad if pushed really hard. I know some really fast guys that run the Hankooks and the Kuhmo V710s. The biggest draw back on thoses is availability. Many times during the middle of the season, they haven't been available. I believe some of the Hankook drivers at Nationals ran another tire, because they couldn't get the Kooks.

 

That being said, I really like the Hoosiers and have never had a problem getting them. I've been on them from the get-go and they seem to work well even when pushed hard !!! They also have a great contingency program with NASA and thier engineers are always available for help and info when needed. Plus they are only about an hour and 20 minutes up the road from me, not across the ocean....

[ELEPHANT1]

I've heard from guys running the BFG's that they are pretty good to start but fall off pretty bad if pushed really hard. I know some really fast guys that run the Hankooks and the Kuhmo V710s. The biggest draw back on thoses is availability. Many times during the middle of the season, they haven't been available. I believe some of the Hankook drivers at Nationals ran another tire, because they couldn't get the Kooks.

 

That being said, I really like the Hoosiers and have never had a problem getting them. I've been on them from the get-go and they seem to work well even when pushed hard !!! They also have a great contingency program with NASA and thier engineers are always available for help and info when needed. Plus they are only about an hour and 20 minutes up the road from me, not across the ocean....

 

Yeah, was very interested in the Kooks but if supply is a problem and Hoosier is stepping up contingency then I might as well stick with something I know and love. ; ) Time to rekindle my relationship with my good Hoosier source. ; )

 

Cheers.

[jvanhouten]

I'm curious about what you are referring to when you say "with the "better" DOT-R ratio" above?

 

Just that you can have 1.5 less lbs per HP with DOTs--14.5 vs 16. So with my car at ~157 HP/TQ and at 2500lbs (closer to 2600 in race trim), I don't think the slicks make up for the 10-% less lbs or 10+% more HP you can run with DOTs in that HP/weight range.

 

I've decided to move back to the Hankook DOT-Rs from the F200 slicks since there are no more to be had for $100 a pop! And, I wasn't able to reduce camber (in the rear) to really make use of the slicks anyway. I've got right at 300 lbs. I can loose by making the switch.

 

Luckily, I was able to get the camber/toe right at where the Hoosier bias slicks like it--.5 deg in the rear and 1.25 deg in the front on my car. The nice things about the tires is that they are _so_ much lighter than the DOTs. They certainly drive a lot different (much higher slip angles) and I wasn't driving them at the limit everywhere. It is a very different feel that wouls take some getting used to.

[cosm3os]

UPDATE:

 

I'm ready for the cage. The doors are gutted, all the tar is out, most of the wiring is out, HVAC stuff is all out. Need to weigh and dyno to find out where I will class, but I'm pretty sure I'll need about 200 lbs of ballast to stay in GTS2. Got the fire system and the cool shirt system ready to install.

 

 

Pics:

 

[cosm3os]

Still getting tar out. Wiring's done. Decided to preview the livery: