Going to dragstrip on friday, any 1/4 mile predictions?

[Guest scottjuly79]

I am going to the drags on Friday (elevation 24ft.) does anyone have any predictions for my E.T.? My previous best was 14.034 at 101mph, that was with a stock 82ZXT engine at 10psi. with an n/a 5 speed, 3.54 gears, and 2.5 inch crush bent exhaust.

 

I am now running the same internals with a T3/T4B turbo, 3 inch mandrel bent exhaust and downpipe, SAAB 900 intercooler with 2.5 inch piping, Merkur 370cc injectors, adjustible FPR., blow off valve, n/a ZX 5 speed, 3.54 gears, and an ACT 6 puck clutch. I will be running 13psi. to start and may turn the boost up to 15psi. I really want to run 12's. If I can't do it now with stock electronics I am sure I will be able to do it when I get my Greddy E-manage going! (coming soon)

 

My prediction is 13.1 at 108mph! (if I don't explode my R-180)

 

I will try to post a Video if I can get my hands on a digital camcorder!

[Lockjaw]

I think the NA 5 speed is going to hurt you a little bit, but the 3 inch exhaust will help alot. I ran a 13.5 105 on my set-up on street tires in a Zx before swapping to a 3 inch exhaust, and dropped to a 12.93 at around 111. I was running around 18 to 19 psi.

 

You will probably be about right on what you guessed, if the track is hooking and you can launch at higher rpms, then you may run a little better. I usually launch around 3500, and have found that dumping the clutch gets me the best times.

 

Good luck, and I would like to know how the clutch does.

[Guest bastaad525]

GAAAAAAAAAH so I was right..... about 14 flat should be all I can expect from my '72 after I put the '81 ZXT in there... I figured about a 14, but was hopeful after Jersey pulled a 13.3 in an almost identical setup. When mine is done it will just be the stock turbo motor, with a 1G dsm blowoff valve, dawes devices boost controller, possibly an FPR if I feel the car is running lean on the top end, and 3" non mandrel bent exhaust straight out the back of the car, no muffler or cat. Mind you though it will be crush bent, I'm right now looking at how I can route the pipe with as few or as least severe of bends as possible, I'm thinking it wont cut down the diameter more than .5" or so. Car weighs about 2600 with me in it. I'm also running the N/A five speed (why would that hurt? are you talking about compared to an AT or to the BW five speed?) and I'm running a 3.9 diff..... THAT will probably hurt but it will get me outta the hole off boost faster.

 

Lockjaw - over half a second from exhaust alone is niiiiiiiiiiice that is friggin amazing... if only N/A engines like the one I have now could benefit so much from something so simple Do you think being non mandrel bent 3" over just stock could make anywhere near that much difference on 10lbs boost?? Try to picture the routing I'm talking about too, most severe bend in it would be close to 45 degrees... so not too bad like it is with the 90 deg bends with the muffler present. Plus no muffler and cat means even less restriction.... What do you think? Would the extra cash for mandrel bends still make a big difference?

 

By the way Scott, what year is your Z? Any idea what your car weighs? When you said elevation 24ft did you mean 2400 ft? This would be good as that means you'd definately have been into 13's at sea level. Well good luck on getting low 13's this time, I think you'll get there easily if you can hook up.

[Drax240z]

Nope he means 24ft.

 

Hey scott, are you heading out to mission raceway? Do they just have open track on Friday nights, or is their other times as well? Gonna have to get my Z out to the track sometime...

[Lockjaw]

No I think you need mandrel bent 3 inch, and that makes a huge difference, even if it is just under the car to the back.

 

You lose at least 20 percent on crush bent. Spend the money, do it right the first time. make sure there are no lips in there either, they cause turbulence.

 

If you buy the stuff, most shops will weld it up for around 100 bucks. Its money well spent, and in my humble opinion, the best bang for the buck mod to do on a turbo Z.

[fl327]

downpipe, need a downpipe and an exhaust. factory downpipe is horrible.

[Doug71zt]

I second Lockjaws opinion on the exhaust. Scott - I'm coming out to Vancouver for work for the next 6 weeks - PM me - we got to hook up for Mission - I usually go out with the guys from work - Mustang SVT Cobra boys - put I'd love to see you run the Z.

Good Luck - Doug

[Guest bastaad525]

*sigh* it's gonna have to wait then.... I'm out of $$$ for now, every last penny I had is going into just getting the engine in there with a few extra parts. I figured since a lot of people say that 2.5" is good for a turbo than 3" non mandrel bend would not be any worse than 2.5 mandrel. And anyways I am stuck with the stock downpipe for now, but in a way that's better..... I'll get a better one made and then go mandrel all the way back too.

[Guest scottjuly79]

My car weighs 2490lbs (2670 with me in it) with a full tank of gas. I think a 72 240 would be at least a 100lbs. lighter, they say every 100lbs. is worth a tenth.

 

I like the n/a 5 speed with the 3.55 gears, they provide enough load that I can get quality boost levels before redline in first gear.

 

By the way, I just installed my ACT clutch disk, and well....... it grips so well that I toasted the spider gears in my R-180 after no more than 50 kilometers of driving. I am replacing it with the same ratio R-180 tonight. (the old diff. already had some serious issues before the clutch swap)

I will still make it to the track tomorrow night, I can't wait!!!

[Lockjaw]

2.5 mandrel would be better then 3 inch crush bent in my opinion. You want smooth transitions, especially in turns.

 

Put it this way, a mandrel loses only 2 percent per 90 degree bend.

 

Also get a good straight thru muffler like a Hooker Max flow or dyno max or something. It won't hurt you at all power wise, and it will keep you from getting a ticket. My maxflo was only 50 bucks.

[Jersey]

You should get 12's Scott. You've got a much better set up than i do and i pulled a 12.88. I'm thinking 12.5! Hopefully the R180 install went smooth for you last night and you make it tonight! Keep us posted and good luck. Get video if you can!!!

[Guest bastaad525]

My car weighs 2490lbs (2670 with me in it) with a full tank of gas. I think a 72 240 would be at least a 100lbs. lighter, they say every 100lbs. is worth a tenth.

 

Yep about 100lbs in difference.... I'm a bit heavier than you though so actually like 70lbs. I could have lowered it a bit also if I had pulled my tools out of the car and of course the spare tire.... kewl well so I'm back in 13's by the barest of margins... in my head at least

 

Cant wait to see what time you post now.... now that Jersey mentions it you probably are good for 12's with such a nice setup. You guys are now in league with some of the fastest production cars in the world.... not much made out there that can touch you.... I can't wait to get there myself

[Lockjaw]

I hate to burst bubbles, but a 12.5 is getting down. You guys have much lighter cars, which helps, but you have to really get some good traction, and have a good 60 foot time to get down there.

 

YOu have to either have really sick power, or get everything just right. not saying it cannot be done, and I think I could run a lot better if I was not pushing 3150 pounds down the track, but just the same, mid 12's takes some work.

 

Good luck with your runs.

[SleeperZ]

I hate to burst bubbles' date=' but a 12.5 is getting down. You guys have much lighter cars, which helps, but you have to really get some good traction, and have a good 60 foot time to get down there.

 

YOu have to either have really sick power, or get everything just right. not saying it cannot be done, and I think I could run a lot better if I was not pushing 3150 pounds down the track, but just the same, mid 12's takes some work.

 

Good luck with your runs.[/quote']

 

I'll testify to that. I may not be the best driver, but I'm finding it quite the challenge to get my launches down consistently - I've hit a 1.9 before, but more often than not, I'm hitting 2.1 and 2.2. To get a 12, your gonna have to hit that 60' hard.

[Scottie-GNZ]

I agree with Lockjaw and SleeperZ on that. The ACT 6-puck clutch and street tire combo is going to hinder you badly. Great combo if you are entering a burnout contest

[Guest bastaad525]

well high 12's maybe and yes I too can testify an ACT and street tires can make launching a pain! I have to launch at very low revs to not spin them all thru first, or if I slip the clutch just right I can get really good launches. I've been thinking about this one a lot..... there are a couple guys that rigged two of Dawes/Grainger type boost controllers, routed thru a solenoid with a switch in the cockpit, to get a low and high boost level, just for this purpose. I'm thinking of doing something like this... launch at low boost, get it moving then switch to high boost, would this make some good difference in the 1/4? The whole setup should cost well under $100 if you're making the controllers yourself... I just bought all the parts for one for $18

[Lockjaw]

You may get a high 12. I ran a 12.93 on regular street tires and pump gas on my old turbo, but I had a 1.9 60 foot time, and I was not leaving hard, I don't know really how I managed that.

 

I figured with DR's, I would drop alot, but I didn't. I have run a best 1.8xx 60 foot time, and have really only dropped about 3 tenths of a second, and picked up a few MPH. In fact I dropped to 12.7xx's the first time out on DR's, and ran 12.65 on a hotter day.

 

Then swapped turbo's and put in a different intercooler, and only dropped to a 12.59, but that was back on pump versus race gas.

 

Jersey's car runs good, no doubt about it, but I would consider his to be a stout runner rather then the norm. I have known several people running the stock turbo in the early Z cars, and they usually all hit a wall around a 13.1.

 

I hope you run what you want, but the faster you go the harder it is to go faster.

 

And work on the first 60 ft, you will either run your time or not based upon that. I launch about 3000 to 3500, and don't slip the clutch, and that gets me the best results. One day I am going to do one about 4500 and see what breaks. HEHE

[Guest bastaad525]

Lockjaw or anyone, what do you think about the two stage boost controller, to help get you off the line and then flip the switch and GO?

 

And I agree I've been looking around reading up and Jersey certainly seems to have exceptional (read: not normal) results in his car, compared to other similar setups.

 

For me all I need to be happy is mid-low 13's enough to run with just about anything out there, still safe and relatively cheap.... what more could you need? dont answer that

[Jersey]

Thinking about that 6-puck now...it may be tough to slide that thing and get a good 60' but, i think if he gets at least a 2.0 or better, he should be able to pull mid 12's, no? I pulled the 12.8 with a 1.9 60' and his setup is above and behond what i have - T4b, 370cc injectors, 3" MB exhaust, AFPR. If he's able to crank that thing up near 14-15psi without detonation, AND is able to get it out of the hole without too much spin, I'm thinking he should fly. Guess we'll see. Hoping he crushes the 12's!

[Guest bastaad525]

I never had a problem slipping the 6 puck.... just have to rev higher... I'd be afraid to do it in a 1/4 mile though as I might heat it up too much and it would stop grabbing or something. My best consistent hand timed 0-60 times were with clutch slip, I would think it'd get a better 1/4 time if you were dealing with not being able to get traction off the line.