Battling Jeff Young's TR8 at VIR

[SPiFF]

CMP isn't the greatest either. But, damn, it is awesome at VIR and RA. Just need to have 3 boxes for this car.

* RA/VIR/RRR (and probably AMP)
* CMP and other mickey mouse tracks
* Daytona/Lowes

[Matt93SE]

Good food for thought Matt! I've been figuring out what to do about that stuff myself... What size tire/wheel do you run? I currently have 45r15's and have to go to 5th at 88 or something like that :/ At LRP I shift to 5th going down the hill!

So yea, to the OP I don't like my 5th either! lol

Chris, I run 235/40/17 on my car in STU. it's a pretty short tire.
At the TMS race two weeks ago I was running 245/45/17 hoosier wets. I was at redline in 5th with the 4.6. doing the math, that was like 134 or 136mph. in the rain!

This goes against everything people have been doing for years. Zsolt's box will only work at few tracks like this. At Daytona there is no way it would work.

Eh? what you mean? the issue is the horrid spacing between stock gears in tons of street cars. In my case at that track, I can use gears 2-3-4 with the 4.1 rear end or I can run 3-4-5 with the 4.6 rear.

with the 4.1, my final ratios in each gear are: 13.55, 7.76, 5.34, 4.08, 3.10

With the 4.6, ratios are: 15.28, 8.75, 6.02, 4.6, 3.50

So if I use the 4.1, my USED gear ratios in 2,3,4 gears are: 7.76, 5.34, 4.08
If I use the 4.6, my USED ratios are: 6.02, 4.6, 3.50

My overall ratios are shorter with the 4.1, which means more revs/mile. that means more power pulses put to the ground and overall more speed.

It sounds counter-intuitive to run a taller final drive, but in my case it makes sense when you do the math and it works.

[bamfp]

Chris, I run 235/40/17 on my car in STU. it's a pretty short tire.
At the TMS race two weeks ago I was running 245/45/17 hoosier wets. I was at redline in 5th with the 4.6. doing the math, that was like 134 or 136mph. in the rain!



Eh? what you mean? the issue is the horrid spacing between stock gears in tons of street cars. In my case at that track, I can use gears 2-3-4 with the 4.1 rear end or I can run 3-4-5 with the 4.6 rear.

with the 4.1, my final ratios in each gear are: 13.55, 7.76, 5.34, 4.08, 3.10

With the 4.6, ratios are: 15.28, 8.75, 6.02, 4.6, 3.50

So if I use the 4.1, my USED gear ratios in 2,3,4 gears are: 7.76, 5.34, 4.08
If I use the 4.6, my USED ratios are: 6.02, 4.6, 3.50

My overall ratios are shorter with the 4.1, which means more revs/mile. that means more power pulses put to the ground and overall more speed.

It sounds counter-intuitive to run a taller final drive, but in my case it makes sense when you do the math and it works.

Meaning people always think they need a shorter FD. You need what works for the tracks you run and the RPM range the engine makes the most power. Keeping Zsolt's car above 6000rpm is key to making it go fast.

[CRallo]

Thanks for the info Matt! I need some taller tires short term and will start looking for an FD...

[Andy Bettencourt]

Really a great job with the power development on that car. It really seems to be able to keep pace with what should be one of the fastest ITS cars in a straight line...

[tnord]

add 100lbs!!!

[JeffYoung]

Actually, I think most of the cars up front are now pretty equal top end. I certainly have more mid range but as you can see I'm working on some handling issues.

GSR is what, 2600 and about 175ish whp.

I'm at 181 whp (peak best, most plots are high 170s), and a spec weight of 2560 but running at 2650 right now. Trilink and other stuff added about 40 lbs.

Top RX7s are high 170s/low 180s and 2680 (I think).

Z cars are low to mid 170s and 2430 or so.

Only car out of whack if the numbers I've heard are right is the Miata at 165 whp and 2380 or so. But that's just sour grapes on my part...lol...

Really a great job with the power development on that car. It really seems to be able to keep pace with what should be one of the fastest ITS cars in a straight line...

[SPiFF]

GSR is what, 2600 and about 175ish whp.

Don't forget the 125 torques!

[Andy Bettencourt]

Only car out of whack if the numbers I've heard are right is the Miata at 165 whp and 2380 or so. But that's just sour grapes on my part...lol...

About a 45% increase?

[Butch Kummer]

CMP isn't the greatest either. But, damn, it is awesome at VIR and RA. Just need to have 3 boxes for this car.

* RA/VIR/RRR (and probably AMP)
* CMP and other mickey mouse tracks
* Daytona/Lowes

Just got back from VIR and saw this, but we run the same rear gear at Charlotte (Lowe's) as RA/VIR/RRR, but then maybe you guys carry more speed into NASCAR Three than we do!

[SPiFF]

Butch, I think our 2 cars are just a little bit different ....

[JeffYoung]

Zsolt your car has better aero and may be different, but I run a 3.45 at Roebling, VIR and Daytona -- and do not run out of gear. I think our cars are going to be aero limited around 140 tops, and Charlotte will be the same. But we will see.

[SPiFF]

Jeff, I was talking about Butch's "thing" and my GSR. I had my street GSR at 140 indicated up there on I40 going to Raleigh, so we will see. I do need to start doing gear dev for Daytona and Lowe's before I run out of time.

[Chip42]

Zsolt - nice vid, thanks for posting it.

what is your FD gear? I've a friend down here in CFR (you know him) who keeps getting super-short, custom built gears in his GSR and they keep having problems (mechancial) - evidence supporitng the case to abandon the direction would be helpful, though I want to crunch the numbers with him as his may be the right course for a box suited to certain tracks (he relaly only runs daytona and sebring on a regular basis).

[Butch Kummer]

Jeff, I was talking about Butch's "thing" and my GSR. I had my street GSR at 140 indicated up there on I40 going to Raleigh, so we will see. I do need to start doing gear dev for Daytona and Lowe's before I run out of time.

You need to leave my "thing" out of this , but in our cars we see the same top end (just shy of 160) at CMS as we do at Road Atlanta or Roebling. Even if I don't do a confidence lift into NASCAR Three (which I've not worked myself up to yet) the corners are tighter at CMS than Daytona so the car binds up and limits the top speed more than I thought it would. At Daytona we'll gear the car for 178-180 and just let the big dog eat.

As always, YMMV...

BTW (and I'll post this on the other thread as well), the CS has agreed to split grid qualifying and a split start for Group 3 at Road Atlanta this weekend (SRF & Other "things" ).

[JeffYoung]

That's what I was tryign to say -- we have the same terminal velocity in the S cars at Roebling, VIR and Charlotte.

Daytona, differently animal, but not by much. I think I got up to 138 or so with the "old" motor, so interested in what the new one will do down there.

[Bryan88]

That's a good video.......good racing.....

I have to agree with the other guys in this thread......add 100 lbs. to both cars......LOL

[Mazmarc63]

And for another datapoint, I use a 5.13 gear in my Rx-7...period. Shift at 8500.

Zsolt, great video. While you guys were battling at VIR, we were battling at Daytona. The new pavement is spectacular. Its a different track.

Looking forward to seeing you guys race there...in my mirrors

[Ron Earp]

That was a damn good race and video. A couple of us watched it last night in more detail and it was very entertaining. Zsolt, I wanted to hold your foot the the floor a couple of times! Jeff Young drove a damn good race there as well, very strong showing in the TR8. Ditto for Chuck Hines, he was rolling out in the green machine. One more lap and one of you two might have been in first, too close to call.

[JeffYoung]

Now, in my experience, people don't start talking smack unless and until they being to worry they may lose......lol.....

Will try to make it this year. I'd say it's 50/50.

And for another datapoint, I use a 5.13 gear in my Rx-7...period. Shift at 8500.

Zsolt, great video. While you guys were battling at VIR, we were battling at Daytona. The new pavement is spectacular. Its a different track.

Looking forward to seeing you guys race there...in my mirrors