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From digest.v7.n63 Wed Aug 6 21:41:51 1997
From: "Thomas, Skaria" <Skaria-Thomas_at_deshaw.com>
Date: Wed, 6 Aug 1997 21:50:32 -0400
Subject: <M3> <MISC> Re: Drag Racing tips requested! LONG

I wish Vlasis was still around so he can give his thoughts... but having done around 40 quarter miles with my current setup, I can help some out here. BTW, I no long have the blower, but currently have the following mods: 1. K&N cone filter, 2. t-body, 3. headers, 4. exhaust, 5. ERT/Jim C. chip, 6. larger fuel injectors, and 7. 255/40/17 tires. I mention the last mod, because I believe it actually decreases my quarter mile time... ;-( (by effectively making the gearing taller; currently have a 3.15 and causing more drag up front). If you noticed, all the big guys have HUGE rear tires and bicycle tires up front. Of course, these cars can't do anything but go straight.... ;-) I am dying to get the 3.46 final drive... hopefully at the end of this month.

>>1. How much does temperature factor into your time? It was around the
>>mid 80's during the runs. Would a temperature difference of 10
>>degrees result in as much as a quarter of a second difference in time?

The external temperature contributes greatly to an increased temperature in the engine cabin. This is the air that the engine breathes in when you have a K&N cone filter element. I relocated the ambient temperature sensor to a very close proximity of the K&N... and I have observed a 120-125 F reading on it when I get ready to stage on a 90 F day! This relationship does not seem linear, since on 70 F days, I get about a 100-105 F reading. So, keep your hood open until the last possible moment... in addition, I added the imfamous ;-) "ram air" setup to my car. I re-routed the left brake duct to the vicinity of the K&N. This definitely helps in street use, but the effect is very negligible at the drag strip. Not enough time or distance in a quarter mile to cool the engine cabin air.

>>2. By how much should I lower my tire pressures in the rear? During my
>>runs, I actually didn't do anything about this, so I would say I was
>>running with about 43 psi (39 psi cold-tire pressure). [Is 39 + 4 = 43
>>accurate?].

This depends on the tires.... R1s as opposed to regular street tires. The R1 like a much lower pressure than my Toyo Proxes T1s. I ran with the R1s at 34 psi cold in the rear and 36 psi cold in the front when I ran my best time: 13.97 sec with a trap speed of 100.6 MPH. I only broke 14.0 sec barrier once with my current setup although I have done 14.0x sec many times. Usually on a cool night...

>>3. BMW says that the quarter mile on the 95 M3 is estimated to be 14.5.
>>From your experiences with your cars [E36 M3 owners], is this accurate?

I think it is accurate... as a general average. The mags post better times.... and I know people who have run much better times. You also have to take in wind conditions, temperature, etc. In C&D magazine, they did a top speed test on a Corvette that Ligenfelter designed for them... if I remember correctly, the top speed was off by 10 miles depending on which way they went.

>>Incidentally, there was a 97 M3 (pure stock -- no K&N, even) that got a
>>14.7 quarter mile. My mods have been removing the baffle, drop-in K&N,
>>and installing the euro-snorkel. I guess I was expecting to come in
>>with a time of at least 14.5, but didn't get near that. Driver

The launch is the most important part of the quarter mile.... you should check you 60 ft times. If your in the mid 2 sec range, that is not good. When I first started this, I was consistently running in the high 14s until Vlasis and I discussed alot about what RPMs to drop from and how to release the clutch and get on the throttle. IMHO, with my current setup, I launch from about 3000 RPMs and slightly slip the clutch on launch and put the throttle down. I do not floor the throttle... this has always resulted in a inordinate amount of wheelspin. Also, do not lift when you feel the wheelspin, keep it constant and when you feel it catch, go down with it. I remember Carl and a few others posting about this some time back and if I remember correctly, they launch at higher RPMs. For me, the Toyo's are very hard and anything higher results in too much wheelspin. One other thing is the RPM at which you shift... Both Vlasis and I tried the "close as possible to redline" method. This does not work unless you have a blower where the HP peak is past 6500 RPM. I usually shift out of first at 6800 RPM, then 6400 RPM, then at 6200 RPM and then ride it to the end in 4th gear. Check out Gene's AG Performance web page.... he posted an optimal shift chart for a stock 1995 M3.

I think we go to the same strip... Englishtown in NJ. On the road back after a run, there is a weigh station. Weigh your car... My car weighs about 3260 lbs with me in it (my weight is 140 lbs). So, do anything you can to lighten the car: weight/power ratio is key. Do not go to the strip with a full tank of gas. Go there with less than a quarter tank and put 2 or 3 gallons of the unleaded 100 octane gas that they offer there. One last piece of advice, AVOID the water before the staging lane at ANY cost. They are meant for the monster cars with slicks on them.... they do a huge burnout on the water to get their slicks very gummy -> great for launches and DEFINITELY not meant for us in street tires.

Hope this helps.

  • -Skaria ///M3 Fan - 1995 M3

PS I will be at Englishtown this Saturday... give me a call if your heading out there.

  • -- Skaria Thomas D.E.Shaw & Co., 120 West 45th Street, 39Fl, New York, NY 10036 tel: (+1)-212-478-0848 fax: (+1)-212-478-0101 pager: (+1)-800-539-5681 e-mail: skaria_at_deshaw.com
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