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Old 09-26-2007, 02:05 AM   #1
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Default How To Launch With Direct Port?

I got a 99 with a 100 shot direct port with every dodad and gizmo available. I have a hard time launching it with the nitrous at the dragstrip. My best 60' without nitrous was a 2.31 with stock 185 tires open diff. My best nitrous launch was a 2.47' 60'. I can never get it to hook up and it's even harder when the nitrous 'hits' I had the controller set to a 50 shot and ramp to a 100 shot in .3 seconds, but even the 50 was enough to break them loose launching in first.

I was launching around 4500, and when the nitrous came on, it would start spinning badly. Now, I have some Yokohama 225-50-15's, so traction should be better than before. I have not tracked it since but I'm planning on racing friday night.

Right now, I have a wide open switch under the gas pedal, so when I floor it, it sends a signal to the window switch. If the rpm's are between 3900-7200, it sends a signal to the controller and the controller turns on the solenoids.

Here's how I launch. I warm up the tires for 6-8 seconds. I stage at the light with my right hand holding the e-brake enough to keep me from rolling, clutch is in, shifter in first. I bring the engine to around 5K and hold it there, nitrous system armed, waiting for the tree. On 1st yellow I drop the e-brake and on 3rd yellow I go. I ride the clutch and roll on the throttle simultaneously. This usually results in a poor launch with my old tires. I would usually spin. My best launch is when I floor the engine and then ride the clutch to launch, but i can't do that or the nitrous comes on.

So, here's my idea. I will mount another microswitch on the clutch pedal in series with the microswitch on the gas pedal, so the nitrous will only come on when the pedal is high enough off the floor that the clutch is fully engaged. That way, I can floor the engine and ride the clutch and not worry about the nitrous coming on while I'm riding the clutch, trying to launch. Of course, I would have to launch correctly so that I'm not spinning when I fully release the clutch and the nitrous comes online. This would also allow me to speed shift without spraying.

What do ya think?

I'm thinking of rejetting to a 125 or 140 shot. Anyone sprayed that much on a stock engine? Assuming a good tune and all, it should take it, right? Got any advice on how to launch? Am I going to destroy my rear end?(I think I know the answer to this one, but only one way to find out!)

I've run about 6 bottles so far and comrpession is sitting on 185 on all 4 cylinders, same as before I installed the nitrous. Plugs look fine, but It will probably get new ones anyway, 2 heat ranges cooler.

I'm trying to get someone bring a camera friday night so I can post a video. I'm hoping to break in the 8's in the 1/8 mile. So far .0068 reaction 2.47 60' [email protected] is my best time. That was before all the headwork and new tires.

Any help is appreciated. Thanks!

PS. I fixed my controller, it had a bad ribbon cable.

Last edited by patsmx5; 09-26-2007 at 02:09 AM. Reason: spelling
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Old 09-26-2007, 02:32 AM   #2
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any way you can set the window switch higher? say 4500 rpm? Come out of the hole at say 4 grand, That way the car shouldn't bog badly, and you'll be on the juice shortly after your 60ft....

I doubt that theres a way to get the gas to help you on your 60fts without at the very least drag radials
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Old 09-26-2007, 02:36 AM   #3
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Yea, I have a MSD Digital 2-way window switch, so I can adjust the on and off settings up or down in 100 rpm increments. That's not a bad idea. Yea, I've been trying to use the gas on my 60' but it's pretty hard.
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Old 09-26-2007, 03:21 AM   #4
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LSD, and dont burn rubber before launching unless your running full race tires. Heating a street tire only takes rubber off and does nothing to add traction. And make sure to avoid that water.
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Old 09-26-2007, 03:48 AM   #5
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ive heard on street tires you just wanna do a quick half-sec spin to clean the tires of dirt and debris and no more as heating them will take the rubber out of its most efficent (grippy) range. As for traction, not much is gonna help less of better tires and a rear end that puts the power to both of em. As it is, anything above 10psi spins first gear 4500 to redline if i just mash the throttle ... even with a clutch lsd and Falken Azeni tires. Point is that with one 185 profile tire hittin the pavement, you cant expect much more than stock power to hold.
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Old 09-26-2007, 04:35 AM   #6
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I'm at 200whp and I can spin 1st at anything more than half throttle. Launch off the nitrous and engage it around 5k once you are hooked up.
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Old 09-26-2007, 08:12 AM   #7
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Back when I had my 50 shot w/ my FM II turbo I had the microswitch to the pedal and another flip switch mounted under the radio right in front of the shifter so that I would engage it in 2nd gear right after the 1-2 shift. Then it would engage when I hit WOT with the microswitch.

The only way you'll hook up in 1st with a 100 shot coming on line is to run slicks or activate it way light like Savington said, 5K or later.

Frank
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Old 09-26-2007, 09:08 AM   #8
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I'm no help as far as the nitrous is concerned..

..but getting into the 8s ought to be a cakewalk. My CRX was doing 9.0s n/a.
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Old 09-26-2007, 09:50 AM   #9
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Pat you are right the 225's will be the key to this. Setting the nos to come on at 5K should help as well i doubt you breack anything solong as the system stays as stabile as it has for you so far. I found that at stock power or a little bit better i got real nice launches at 4500 rpm with my 225's. Now with real boost the 22'5's are feeling kinda puny and i am looking for more traction. It is a vicous cycle, make more power need more stuff to get it down. But what else would we do with out time. Also a short burn out is best. Esp if the track is VHT'd. That **** makes for some real nice launching.
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Old 09-26-2007, 11:40 AM   #10
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Alright. Everyone seems to agree that a quick 1/2 second burnout just to clean the tires is all I really need to do. Ok.
Yes, they do VHT the track.

A few have mentioned raising the on setting to 4500. That's not a bad idea, I suppose. I'm still liking my idea about putting a switch on the clutch. If anything, it would keep me from accidentally spraying while I launch it.
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Old 09-26-2007, 12:06 PM   #11
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how about using a steering wheel mounted switch instead so that you have ultimate control over when it comes on? I know its just one more thing to focus on during a drag launch, but it would make a difference ... and its not like you are turning the steering wheel a lot during a drag lol.
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