Max boost for factory turbo

[OhioC5]

I guess I'm asking how far to turn up the boost with the factory turbo until it's worthless. I'm at 20 lbs now, no KR, and still tuning. I want to go to the track tomorrow for the test and tune night.

Alky kit, 36 lb injectors, power plate, dutt neck, adj FPR, TT chip, HD actuator, CAI kit, dual 2.5 pypes, no cat, factory down pipe. I think that's about it.
I would really like to see low 13's but I know that's probably not going to happen without sticky tires. Since I turned up the boost to 20lbs today the rear tires break loose pretty easily.

 

[bmackinnon]

You should be in the high 12's at 20 psi, with your mods, at least, I would think... work on the tune and the launch... I'd venture that you are ready for a new downpipe... 3" will be plenty.... 3.5" is overkill (and doesn't fit worth $hit) unless you are looking for low 10's... you are not going to gain alot at this stage with increased boost... maybe 21-22 psi and then you are just fighting the heat/knock with the stock turbo.... you may gain more by staying at 20-21 psi, and adding timing and fuel... at least that's my guess.... I'm SURE others will/have done alot more with the stock turbo... Tim Stockwell went 10's at like 30+ psi in the early 90's.... but it takes a perfect tune and a lot of luck.... and they were on the ragged edge...

 

[DCVING 6]

From what I've read, most find that after 22-23psi the stock turbo becomes inefficient. The amount of heat it creates after that point negates any gains from the boost.

 

[Onalky87]

Go to track and turn it up till it don't pick up ne mph or starts to knock. Then add timing. While making sure to keep and eye on ur KR and a/f this whole time

 

[OhioC5]

I'll give it a shot, been ading timing back with no sign og knock so far. The Mv are 780-800 range.

Fuel Fuel Timing 1-2 Timing 3-4
(1) 128 (2) 128 (3) 124 (4) 118


Prior to ALKY It was:
(1) 154 (2) 154 (3) 116 (4) 116

I'm thinking I should be able to slowly bump up the timing in the 1-2 gears 6* and 8* in 3-4. Going to run and take some notes, we'll see what happens.

 

[murphster]

Good advice so far. I would go up to 22psi or so, which is enough to go high 11s. The gains are small after that.

If its an alky TT chip, the base timing should be 23/21. If you want to be safe, run something like 22/20 which would be (3) and (4) set to 125. I've never had issues running that timing on alky with a stock combo, as long as the alky is working normal.

When your tune is close to optimal, you'll start out in the very high 700's at the beginning of the run and end at about 750-760. I usually take out a lot of first gear fuel, setting (2) to something like 116 or so. The stock O2 sensor starts to read lower through a run as it gets hotter, even if the A/F ratio remains the same. Safe way to tune is to add WOT fuel (1) so that at the END of a run the O2 reading is 770 or so and then slowly take out 2% fuel at a time and see if the mph goes up as it starts to lean out. I wouldn't go lower than high 740s at the end of a run without an EGT or wideband to back it up.

Good luck!

 

[sweetv6]

22 -23 psi is the max in my case
for a pur stock

setup and setting in my sig

claude

 

[OhioC5]

Times are in, of course I'm disappointed but kind of knew how it was going to turn out. Street tires, not knowing how to tune this thing and first time I've ever had it to the track. I was towing a boat etc etc. Now that the excuses are out of the way. All runs were at 19 lbs of boost, alky dial set on #6 until last run. I decided not to turn up the boost because I knew I was leaving a bunch on the table already.

Initial timing was set at 124 (16.9*) and 118 (14.5*) fuel was chip default of 128

Run #1

2.15 60'
76.5 MPH 1/8
14.12 ET
95.26 MPH

Moved 1-2 spark to 128 (20*)

Run # 2

2.27 60'
76.41 MPH 1/8
14.32 ET
94.86 MPH

Moved 3-4 timing to 129 (18.4*)
Moved 1st gear offset to 123 (-3.9%) I did this because the MV were mid 800's at begininng of run

Run #3
2.08 60'
77.75 MPH 1/8
13.89 ET
97.04 MPH

Moved position #2 1st gear offset fuel to 120 it still seemed fat
Moved 3-4 spark to 131 (19.1*)

Run #4
2.04 60'
77.35 MPH 1/8
13.91 ET
96.48 MPH

Moved 1-2 spark to 130 (20.7*)

Run #5
2.02 60'
78 MPH 1/8
13.77 ET best time
97.68 MPH

Moved 1-2 spark to 132 (21.4*)
Moved 3-4 spark to 133 (19.8*)

Run # 6
2.1 60'
78.96 MPH 1/8
14.01 ET
97.76 MPH

Can't remember change, friend was ready to go.
I believe I bumped up 1-2 spark to 139 (23.9*) and 3-1 spark to 139 (21.9*)

Run #7
2.1 60'
78.96 MPH 1/8
13.73 ET
98.76 MPH

Run #8
2.26 60'
79.25 MPH 1/8
13.97 ET
99.39 BEST MPH

I saw 2.3 knock so I bumped the alky to #7 position on dial
Final numbers 1-2 spark at 142 (24.9*) 3-4 spark at (23.6*) 19 lbs of boost

Last run
Spun the tires hard, was out of the track groove.
2.98 60'
78.67 MPH 1/8
15.0 ET
98.61 MPH

I have a better starting point for next time. Timing is closer to where it should be, it was still fat on the start of the run but ended up a nice 760 at the end.
Any pointers besides sticky tires and learning how to launch this thing?

After looking at the MPH on the slips I just went out and moved the timing back down to 24.2*/22.2* 140

 

[MY T FAST]

i'm far from an expert, but i'd say with your mods you should be running way faster than 99.xx mph. i'd up that boost to 23ish and then add some timing. i have nearly identical mods (except 50lbers and a 3.5"dp), haven't been to the track yet but i'm hoping to trap at LEAST 108. i had a 13.44@99 w/255 street tires before alky at 17lbs and ~21/19* timing. good news is you got lots of free power there waiting to be unleashed. turn it up and give her hell!!!!!

 

[MY T FAST]

ps: just saw you're in akron. i live in columbus, but i'm in rootstown for the next 4 yrs for school and the car will be here frequently in nice weather. lemme know when you're gonna be out cruisin or at the track, i'd love to meet ya.
pps: what track do you go to?

Talon

 

[OhioC5]

Yea, sounds great, PM me your number if you want. I go to a car show every week and cruise everyday. I went to Dragway 42, like going there because you can run as many times as you want. I didn't crank up the boost because I knew it had so much more at 19 lbs. It's at a good starting point for the next track day. Tuesdays are test and tune at 42, I'm ready to go back and give it another shot. You interested?

 

[DCVING 6]

I have a better starting point for next time. Timing is closer to where it should be, it was still fat on the start of the run but ended up a nice 760 at the end.
Any pointers besides sticky tires and learning how to launch this thing?

I think your headed in the right direction. Maybe try to pick up a pair of stock GN rims and a pair of 235/60/15 MT drag radials if you like the stock look. Otherwise the 255 wide is a nice option too, gives a slightly more agressive look.

If you get bad wheel hop with the stickey tires, may need shocks in the rear. My car has only 10k miles on it, but after 24 years, it needed shocks. I like the Bilstien's for a great all around shock.

 

[Wayne A Bender]

I had the same set up as you,accept my injectors were stock plus 100lbs valve springs.I ran a 12.7 at 104mph at 22lbs of boost and 1.7 60ft at 5lbs boost launch.But I also have Mickey Thompsom et streets those are important.I am in the Cleveland area you can pm me if you want.

 

[TurboTnZ06]

I ran my GN at 19.5 psi boost on pump gas and 21* (50 psi base FP) and went 13.0 @ 104 mph. 3" atr external downpipe, test pipe through factory Y to 2" duals, TT chip, 60# injectors, hotwired FP, and a 9" K&N cone. I think you can go 12's too with the stock setup with a good launch. Maybe the alky isn't needed at this low of boost? Try 25psi boost with the alky

 

[OhioC5]

I bumped it up to 22 lbs and still have zero knock. Going back on Tuesday the 21st unless something comes up.

 

[usetaboost]

I played with boost settings quite a bit before I started playing with timing. Going by seat of the pants, 22-23 seems to be the sweet spot. I don't think there's much to gain after that. I did notice a little gain and better throttle response after bumping WOT timing.

 

[notacarlo]

Why care what the ET is? Those 60' times would be my concern. After you get those down in the 1.8-1.6's then start paying atention to the ET.

 

[OhioC5]

I figured out why my car was so slow. The up pipe silicone slide out from under the clamp on the very bottom under the throttle body. I noticed boost juice sprayed on my intake and further inspection revealed the problem. Took it for a test drive and it feels like a completely different car. I managed a 1.9x 60' last night, but didn't know the up pipe was leaking. My butt dyno tells me its a second faster today. Going to run to summit racing and see if they sell silicone couplers and better clamps.

 

[DCVING 6]

Can't wait to hear the new times on the next outing.

 

[OhioC5]

Yeah, me too. I had to lenghten my waste gate rod 5 turns so far. My little turbo was working really hard.