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Discussion Starter · #1 ·
I tracked my '94 TT with BPU, ETTC, and suspension for two years and my '93 MRT BPU and suspension for a few years. The MR2 with 220whp was always ~6 seconds/lap slower on a high speed track like Mosport. I've recently installed a GT28RS DBB turbo on it and at 17 psi it's become a torque monster. As I won't be able to get it out on the track until July to see how it's improved, I've been crunching the dyno numbers, and now posting here for input.

Comparing the torque from 3500-7000 rpm, it very closely matches the stock TT power, but when adjusted for the vehicle weight difference it obviously exceeds it. It actually falls half way between the power a sequential and true twin BPU TT @ 15 psi when adjusted for weight. This "area under the torque curve" power comparison doesn't take into consideration many other factors of course, so I'm curious if any others could share their Supra experiences with, or against, a turbo modified MR2 at the track.

FWIW, data logging shows very close cornering speed for the two cars so the 6 sec. difference was mostly from the straights. The new turbo spools quickly (ie 250ft-lbs by 3250 rpm), and it's transient response seems much faster than the true twins, so it's actual performance might slightly exceed what it's power band indicates.

Bruce H.
 

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Bruce Hadfield said:
I tracked my '94 TT with BPU, ETTC, and suspension for two years and my '93 MRT BPU and suspension for a few years. The MR2 with 220whp was always ~6 seconds/lap slower on a high speed track like Mosport. I've recently installed a GT28RS DBB turbo on it and at 17 psi it's become a torque monster. As I won't be able to get it out on the track until July to see how it's improved, I've been crunching the dyno numbers, and now posting here for input.

Comparing the torque from 3500-7000 rpm, it very closely matches the stock TT power, but when adjusted for the vehicle weight difference it obviously exceeds it. It actually falls half way between the power a sequential and true twin BPU TT @ 15 psi when adjusted for weight. This "area under the torque curve" power comparison doesn't take into consideration many other factors of course, so I'm curious if any others could share their Supra experiences with, or against, a turbo modified MR2 at the track.

FWIW, data logging shows very close cornering speed for the two cars so the 6 sec. difference was mostly from the straights. The new turbo spools quickly (ie 250ft-lbs by 3250 rpm), and it's transient response seems much faster than the true twins, so it's actual performance might slightly exceed what it's power band indicates.

Bruce H.

That sounds like an interesting project. I don't think I've ever seen a MR2T at a racetrack in CA in 40+ events - they're even rarer than Supras, which aren't exactly plentiful. I've always liked those cars. A friend of mine had a NA then a turbo, and they were a lot of fun to autox. How do the brakes hold up with track use?
 

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I have seen a couple of them at willow springs they run good especially on the stretts of willow which is a shorter more technical track.
 

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Discussion Starter · #4 ·
Eric said:
That sounds like an interesting project. I don't think I've ever seen a MR2T at a racetrack in CA in 40+ events - they're even rarer than Supras, which aren't exactly plentiful. I've always liked those cars. A friend of mine had a NA then a turbo, and they were a lot of fun to autox. How do the brakes hold up with track use?
I've never been on the track with one at the same time either except for a bone stock one (slow). I have a '93 which has the larger OEM brakes and they've been great...but then I also run OEM pads on the TT and change them frequently.

Bruce
 

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I've seen some at a few DE events at VIR and Summit Point, but I've never gotten to talk to them about their setups. Thats awesome that you're datalogging everything; you should be able to determine a very concrete answer once it's out there on the track. Let us know what you discover.
As for your question, I have no idea what it will do, but looks like you'll be putting beating up on your Supra's times.
 

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You're seeing the same cornering speeds? The MR2 should corner quite a bit faster based on weight alone... assuming the tires are the same.

For comparison... I can corner as fast on crap tires in the AE86 as on good street tires in the Supra -- with one track day under my belt on the AE86.
 

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Discussion Starter · #9 ·
quick said:
You're seeing the same cornering speeds? The MR2 should corner quite a bit faster based on weight alone... assuming the tires are the same.

For comparison... I can corner as fast on crap tires in the AE86 as on good street tires in the Supra -- with one track day under my belt on the AE86.
Or maybe you aren't as concerned about stuffing the AE86 into the wall :)

Nothing on the mid-engined MR2 is the same actually so it's not that easy a comparison. The rear of an MR2 is just waiting to pass the front at a hint of driver error and one tends to respect that. I had actually just put on new and wider shaved RA1's and a stiffer front bar, so I do expect to see improvements with seat time. The biggest gain may come on corner exit if the new turbo comes on quicker. I always felt like the true twins lagged or had poor transient response despite a good looking dyno plot. It just felt slow coming off a corner, and others I had been pushing opened up some distance down the straight until I caught up again approaching the next corner. If I entered using a lower gear I'd run out of revs before exiting. Do other experience this also with TTC or ETTC?
 

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Discussion Starter · #10 ·
bart97 said:
what does the mr2 weigh?

Mine weighs 2909, and I used 3480 for the Supra but don't know how accurate that really is.
 

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Bruce Hadfield said:
Mine weighs 2909, and I used 3480 for the Supra but don't know how accurate that really is.
I guess that depends on the supra in question mine is under 3100 but for stock you are a bit light at 3480.
 

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Bruce Hadfield said:
Or maybe you aren't as concerned about stuffing the AE86 into the wall :)
Hehehe. This is true, Bruce. The AE86 is also 2400 lbs with 3/4 of a tank of gas, so maybe that has something to do with it as well.
 

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Discussion Starter · #13 ·
I got the MR2 out on the track for the first time on Monday with the new turbo and 17 psi of boost. The track was damp for the morning, but I could tell the new turbo was making a big difference despite not having the data logger hooked up yet. Then the track dried out and a got a few hot laps in. I was able to keep up with friends with NSX's that I could also just keep up with in the Supra, so I think the two cars must now be pretty close. I ran into mechanical problems prior to hooking up the data logger so that will have to wait until next time. So keep your eyes in the mirror for a red MR2 the next time you're at Mosport :)
 

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My brother has a 91 MR2 T w/ about 280 rwhp. I will be running with him at VIR in my SP57 6 speed supra w/ about 400 rwhp this June so I'll let you know how our cars compare.
 

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Discussion Starter · #15 ·
RCGsupra said:
My brother has a 91 MR2 T w/ about 280 rwhp. I will be running with him at VIR in my SP57 6 speed supra w/ about 400 rwhp this June so I'll let you know how our cars compare.
Excellent! I wouldn't want to be the one in the MR2 staring down those two long straights with a Supra filling my mirrors :) Do both cars have similarly improved suspension and tires?
 

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Bruce Hadfield said:
Or maybe you aren't as concerned about stuffing the AE86 into the wall :)
If I had quick's AE86, I'd be very concerned about putting it into a wall! That thing is nice as hell!!! :bigthumb: My '86, however. . .stuffing it into a wall might do it some good :sadance:
 

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Bruce Hadfield said:
Excellent! I wouldn't want to be the one in the MR2 staring down those two long straights with a Supra filling my mirrors :) Do both cars have similarly improved suspension and tires?

Yea, i will have the power advantage, but his car is no slouch either. I have KYB adjustable struts, eibach springs, 8 pt. rollbar, and a front strut bar as far as suspension and added stiffness goes. He has KYB's, race springs, and TRD sway bars for suspension. We will both be on street tires as well. It will also be interesting b/c my dad will be out there with his new Lotus Elise as well. Should be a great time!
 

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Mr2's do have a sweet cornering.... I wouldn't be able to compare it w/ a supra unless someone w/ a TT wants to trade... hee hee....
 
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