8ALTNG

iTrader: (1)

With my 3200 stall convertor, I would leave the line at 10psi and then hit 17psi 30-40 feet out. There is no lag. This is with a 4.8 with a 67mm. I think that you just have to get your rpms up alittle bit more. Also what are the specs on your cam??? What tires did you run on and what rearend gears are you running???

quicksilverado

iTrader: (8)

He has a munual tranny and 3.73 rear.

F8L Z71

Your problem, like stated, is the tranny and gearning.

If I dont build boost off the line I would get 2.1 60's all day long.


"Both videos before final tuing, hense the low MPH and high ETs"

Video of a non-boosting launch

If I boosted to at least 5psi it would hit 1.80-1.85 60's depending on how bad the trans slipped. In the 2nd vid the 60' was crap because of all the bouncing but drop the front end 1.25" and it turned into a 1.80 60'. But you get the idea. You dont get that kind of bucking with lag lol.

8psi then 6psi launch

I think your only hope is a 2-step really.

TURBO8

iTrader: (9)

I was using bridgestone 275-45-20's I have 3.73 with the 6 speed. I cant build boost off the line. You are right I need to get the rpms up. I only got two runs in. It was a lag boging off the line. I have the 02 z06 cam. I could really use a two step. I will try again as soon as it stops raining here. I loose traction at 2500rpms (launching) on the street, the track was preped very well. I'd love to leave the line in boost, the only way I can do it is with a two step!

F8L Z71

Yup, a 2-step and slicks! Street tires wont do squat.

You'll get it man. Just takes some time. My first time out with the STS I was running low 13s at 13psi. After some tweaking by Rick and learning how to launch the thing on boost I ran the 12.3s and at 110mph every run. I hit 3 1.80 60's before the trans started acting funny and lagging durring the shifts, then it was 1.85 twice.

You have the HP and weight to run what I ran easy. I had more HP but you weigh a lot less

You have a nice truck, I cant wait to see it out there tearing up some F-0bodies and Vettes

zippy

i think the gearing of the manual doesn't help, but mainly the fact that he's running a manual is what's killing him. there is no way to pre-load (without killing a clutch) for him and with his system being designed around boost that's bad. in order to pull it off you're going to need around a 5500 launch. one problem that you're running into is when you launch you're only on the engine and when you get into PE mode without boost you're running rich as f**k which just lower's your power until you get into boost. you probably would have ran faster if it would have spun the tires due to getting it into the upper rpm/higher velocity range faster. this would have pushed you into boost by second gear and away you'd have went. a two step would help, but i think if you went to a 2 bar tuning you would without chainging anything be much faster. the engine would respond a ton quicker pre-boost and get you rolling and into boost quicker. with your truck having the bigger turbo you need to get the engine to rev quicker when not in boost which will create exhaust pressure and get you into boost. it's obvious that even with the deep gearing from the first gear in the trans you had plenty of load, hell it took 2.8 to get to the 60'. i think your biggest battle is the engine being so rich when it's not in boost.

vanillagorilla

iTrader: (1)

I've never been to the track with mine and I haven't started tuning it yet, but....

I do get the same bog conditions when launching on the street. If I drop the clutch at 2500 it'll bog, then pick up and go. If I drop it at about 4000-4500 (depending on the surface), I can feather the throttle out of the hole. I've never been to the track with my current setup, but it's by NO means a 2.8 60ft. If I rev it up to 5000rpm and drop the clutch the tires go up in smoke but there is some boost already.

I do have some lag, but by the top of first I have full boost when I roll into the throttle, and of course full boost all the way through second. I have a smaller engine than you with the same turbo, with what sounds like less lag. I would check out your boost leak, wastegate operation and an exhaust leak.

When rolling, if I downshift into second or third, floor it, both my crappy cam and turbo are in by 4000rpm.

I do agree though a 2 step and 2 bar are a must if you're looking for maximum ET.

TURBO8

iTrader: (9)

Thanks for the info guys. I agree, I think the two bar and two step is the only way to go for me. I am not a big fan of the high rpm launching with a 4300lbs truck, but it seams like that is the only way I can launch at the track. The high rpm rich bog, makes sense, that is exactly what it feals like. I do ok on the street launching at 2000rpm. I break lose at 2500rpm. But for some reason, at the track it was twice as bad. (bog) I think I am going to try it again at another track (sears point) to see if I have the same issue. I hear they dont prep the track as good. I also think I have something going on with my wastegate, I have not figured it out yet. A 15lbs spring is only giving me 10-11psi! That is mesured at the turbo and the intake, same reading. But that is another topic!

vanillagorilla

iTrader: (1)

Oh yeah, a nice electronic boost controller would work wonders for you. Get controll over that wastegate man!

TURBO8

iTrader: (9)

I had a gredy spec b it was spiking to 22 psi. I took that off and ran a bleeder valve type boost ***.