Launching

[Fatty]

I'm used to driving things built for power not speed (grain trucks, semi) and i'm having trouble figuring out how to launch. When i have the car revved up and let off the clutch, it jerks a few times instead of throwing me back in my seat. I am more than certain it is my stupidity rather than something wrong w/the car. When i let off the clutch when i do this, i let my foot slip off and let it bang home, is this right? Can i get a detailed step by step for this? Its a 93 eclipse GSX MT. Also, i've heard that running past redline doesn't do you any good in a street race, is this true?

Come to think of it, the car does the same jerking when i let off the accelerator in first gear instead of the typical engine revving/holding the car back i'm used to, is this normal?

[Edited by Fatty on 11-12-2000 at 09:17 PM]

[Zapp]

try revving it up higher, around 5000rpm and slipping it a little

[Fathouse]

Hey Fatty I like your name, lol. But seriously what rpm's are you launching at???? I saunch at 4700 or so with great results. Bring up the revs to 4700 let the clutch out until the car starts to move and quickly let the clutch out the rest of the way and floor the gas. Don't slip it to long or you will burn up the clutch. And if your on a stock clutch it won't last to long. Hope this helps some

Peace Fathouse

[DSM Storm]

Yea, what you wanna do is dump the clutch at about 5000 rpms and hold on to your assole, I personally get smoked off the line by all sorts of cars but then again my clutch slips like a bastard, i aint putting one in till july when I drop in my new motor. As for revving, I usually bring it till redline, im definatly going to look into getting the rev limiter raised to 8500 this 7 grand shite dont cut it. Then again I have an 18G with a 7 degree clip (bummer) does the job though. I might have it clipped 25 degrees. Stock turbo I wouldnt bother going over 6 grand. Good luck.

[ecoli]

Don't drop the clutch, do what the first few guys said. And shifting at 7000 or higher is going to make you slower unless you have a big ass turbo (20G or larger) and/or cams. I would try around 6200-6500. If you feel a big power gain when you shift, then you went too far and left your powerband. With stock cams, your power starts to fall off at 6000...

[DSM Storm]

Ecoli, lemme see if I can understand your post, you mean to tell me that I need a set of cams, a 20 or larger turbo to make power after 6 grand? Uhm..I think not. As for launching, its gonna take a dose of both to see what suits you better. I prefer dumping the clutch, some prefer slipping it, dont know till ya try.

[ecoli]

No, you make power after 6000rpms, but it starts to fall off. If you run it too far, you are going to end up slower than if you shifted earlier. It usually takes time for a human to shift and the needle on stock RPM gauges are slow. So if you wait until you see 6800 on the gauge, you probably aren't actually shifting until you are into the 7000s.

Here is a picture of a dyno run of a 16G 1G, with and without cams. The HP starts to fall off at about 6000 RPMs, you just need to find the sweet spot your car.

http://www.roadraceengineering.com/eclipsetech/mikedyno-webcams.jpg

[DSM Storm]

Yep, we've all seen those impressive numbers on the RRE site, ......take a look at another dyno pull from Mark Hessler using HKS cams 264/272's :
http://www.twingles.com/ettsiawd/dyno_data/
Torque starts to drop at about 4.5rpm and HP starts to drop at about 6k rpms. Now both Marks car and the RRE car both have small 16G's without a clip, you could futher that drop off point by adding a clip to the charger. I mean cams definatly do help, and its obvious that web cams are better than the HKS cams. I guess what im saying is with my clipped 18G turbo, I dont get that drop off feeling you get when you hit about 5k rpms with the stock turbo, i mean its noticable and its time to shift, I dont get that feeling anymore, something that a true dyno pull would show. Like I said in my first post, with the stock stuff, I wouldnt bother going over 6 grand. At my friends shop (Transit Dynamics) Ive witnessed dyno pulls on a 1994 FWD Talon with a charger clipped 25 degrees, and the hp drop off point is around 7100 rpm's using the same turbocharger im using, an 18G, thats why I bought the 18G, because I was impressed with that pull, unfortunatly I was a little intimidated about turbo lag so I didnt get the huge clip, getting to drive that car, I quickly changed my mind.

[ecoli]

What do you plan on doing to run a 8500 revlimit? I want to raise mine a bit also, maybe not that high. I want to do rods and lightened valve train so that I can run it up higher. I dunno how much I would have to do to the valve train though. Would titanium retainers and SS valves be enough, or would I need some stronger springs also. I have a T3/T4 with cams and it wants to pull past revlimiter, I bounce off it sometimes on the street, cuz it never feels like it is leveling off. The track here is so slippery that an extra 500 rpms would be nice in 1st gear.

[DSM Storm]

Im actually building a motor for my 1992 talon AWD, its a 1990 style 6 bolt motor with crowers, 8.2:1 compression Ross racing pistons with anti-det. grooves and a banadized coating, ross rings, all arp hardware, blueprinted and balanced motor, B.R. underdrive damper, unorthodox pulleys, T-trix level 3 head, web cams, web tit-retainers and springs, and more crap to tag onto that. Im actually not going to shift at 8500 but im looking to shift at around 7500 to 8000. I would personally do the web cam spring kit or the crower spring kit along with an arp bottomed end. If you have the cash to do the head and bottom than you know where to go from there.

[ecoli]

Why did you go with 8.2:1 compression pistons? I hoping to score a 1G shortblock and head cheap from someone I know. I have a 2G... I am already scared to tune it to the max and throw a rod. And I don't want to build up the bottom end and then get crankwalk. I was looking into get 8.5:1 compression Ross or JE Pistons, Crower rods, ARP fasteners all around, remove balance shafts, knife edge/balance crank, etc. I don't want have/want to spend the $1500 for a full built head, but I would like to throw on a slightly upgraded 1G head. I have run 117mph on my unported 2g head, stock 2g intake manifold, 22psi and untuned AFC. So I am thinking a cleaned up/mildly ported 1G head and 1G intake manifold might be good enough for me for now. I really want to get a better head gasket and some ARP head studs and crank up the boost.

[AWDMIKE858]

Try pumping the gas , (to build the boost), as fast as you can and watch your boost gauge to see if the boost is going up, try launcing with some boost off the line is basically what I am saying... I think if you just hold the rpms, the boost has to be made when you dump the clutch obviously. But if you can get boost on the line... then the turbo can add to whatever boost you already have and you'll launch harder. My MSD DIS-2 has a built-in studderbox that creates about 7 and a half psi at the staging line... I am figuring out a way to launch it. Right now I have it set at 5500 rpms, and I dump the clutch all at once. I spin the tires tho, which is why I might try to launch around 4000-4500 and slip it instead... Hope any of this helps or gives you ideas... Later!

[DSM Storm]

Well, the reason why im going with 8.2:1 compression pistons is because I dont know what turbo and how much boost im going to crank in the long run. 7.8:1 compression is just too damn low, thats for shitters who dont take care of the car and run 87 octane with high boost. Did you know that pump gas -lets take 87 for instance- can either be ± 3 by state regulations? that means your either getting something from 84-90 octane when you fill up at the station. So if your running 15 psi with 84 octane 7.8:1 comp. pistons are the way to go, as for me, i fill up with sunoco 94. Anyways, 7.8:1 is too low, thats enough to run 36 psi and still have a great tuning window. As for 8.5:1 pistons cannot be pushing 36 psi without proper tuning, as jeff hill when someone jumped the boost on his 90block fitted with 95 pistons, he went from 33 psi to 36 psi and detonated the motor. Now im not certain im going with 8.2, I still have to decide, Ill find out in a few weeks when I order.

[Stephen]

About dumping the clutch, is that basically just holding the gas at 4500(or whatever rpm)
then just letting off the clutch fully as fast as possible with no waiting for it to slide into gear?

This is my first 5 speed and have been driving for about a month, am just wondering the terminology, I understand about slipping the clutch,(like when you just want to move up a little in a traffic jam, you let it engage slightly just to edge up) right?

hehe, I want to know before i just "dump" the clutch the way i think its done and end up needing a tranny rebuild.

Stephen 95 awd tsi 103k and still boosting!

[Fatty]

I tried what you guys said and it didn't jerk. It didn't really launch me either, though. However the snow melted and it was wet so i spun a bit first. I was kinda expecting a little more, i guess i'll have to try it on some dry roads though.