BOOSTAT4500

iTrader: (17)

Finally got the car out to the track with proper tires and tuning. I was hoping for a little better so maybe someone can help.
93' Mustang
SBE 6.0
Twin on3 Performance 70mm turbo's, E85, 14 psi peak, 17 degrees timing
317 heads, untouched
LS1 intake
Custom cam and springs by Martin @ Tick Performance
4l80E
3.31 gears, 28" tire

My 3rd and final pass of qualifying was a 10.64 @ 139. DA was 6500', 3350 raceweight
60'- 1.766
330' 4.780
1/8th 7.089 @ 107
1000' 9.025
1/4 10.646 @ 139.34

I backed it off a touch for the bracket rounds, so mostly 10.8 to 10.9's the rest of the day

My question is on the the first part of the track. I have a 2 step but can only manage about half a pound of boost on the line, at 3700 rpm, foot braking. Without the 2 step I cant even get out of vacuum. So lack of traction is not the reason for such soft 60's. Once I'm going I'll hit about 7-8 psi in first and then 14 at the very top of 2nd, and hold 14 through 3rd.
I have a feeling the turbos are just too big for the motor to really get them going down low, but am hoping for some other ideas to get them spooled up quicker. Thanks

6669camaro

iTrader: (1)

You can give it a small shot of nitrous to help them light up off of the line.

yenkomike

iTrader: (2)

you are loosing 1/2 second in the first half track. whats your tune look like in the low boost area> the turbo's are spooling lazy they might be a little big but the tune will make or break it. what fuel are you running? if that's pump gas you are a brave man at 17* without meth.

post your timing table
cam specs and turbo specs if you can.

RonSSNova

iTrader: (3)

He is on E85. And running in thin air.

Need to look at timing and fuel on the two step. It took some fiddling there to get my single to make boost there.

What PCM? And do you have a log of the runs?
Dumb question, but are you wide open throttle on the two step?

Ron

ablakez28

iTrader: (9)

I run the same turbos on my 69camaro with an SBE 6.0. I run the smaller exhaust housing I believe .68? Anyhow they light off very fast on mine. Maybe run your 2-step up a little higher?

I agree to have a good look at the tune and also be sure there are no boost leaks.

BOOSTAT4500

iTrader: (17)

Thanks. I have thought about a small shot of nitrous, just hoping I can do it with tuning first.

Fuel is E85 with an intercooler. I need to work on the airflow over the cooler though as I was hitting 190 IATs at the end of the run.
The spark at 1 pound is 27 degrees, tapering down to 17 by 7 psi. Then stays at 17 degrees.
Turbos- On3 Performance, 70mm, .68 a/r
Cam- 221/225 .622/.620 115+3

ablakez28

iTrader: (9)

Stock ecu I take it? Seeing any KR?

The cam I run is 228/228, LIft is .571/.571, and is on a 112LSA.

If you are running stock ecu and the 7psi is the last line (i believe) I would have a good amount over 17 in the lines leading up to it. I had to do some tweaking in what ill call the "spool up" zone on both my Camaro and Nova getting them to come on hard and fast.

Forcefed86

iTrader: (4)

What converter?
What kind of boost controller?

Couple things...

Your IAT seems really high for 14lbs on twin 70’s. For comparison my 6.0 with a single S476 sees is under 160* at 20lbs using Treadstones 1200hp IC (32x12x4 I think?). And that’s starting out heat soaked at 120* or so. My IAT will actually drop a ton at the start of the run and work its way back up. I’d make a boost leak checker if you haven’t already. Pressurize the cold side and hose everything down with soapy water. Sounds like you have some leaks….or possibly a poor intercooler?

I agree your 1/8th mile is what’s weak. The power/trap sounds about right for 14lbs to me. 139 at 3350 comes out to roughly 720hp. You have a factory 6.0 with a small cam. The most your gonna do is double the NA hp per 15lbs or so. Doesn’t matter if you have twin 60mm or twin 100mm turbos. Once you get the IAT thing figured out, turn the boost up. That combo has a ton more in it.

Are you sure the WG is staying closed 100% until your target boost level is reached? A lot of times the WG opens progressively as boost is added. With a decent boost controller installed, it will hold the gates shut 100% until target pressure is reached.

Should be able to make more than a half lb of boost at 3700? Do the tires spin? Or does it just stop making boost? Once you make 5-6lbs the turbo usually “lites” and will continue to build boost and RPM. You need a trans brake, better brakes, nitrous, or a looser converter to make this happen. No real way around it. If you have major leaks as I suspect though you might be able to make more boost once they are ironed out.

BOOSTAT4500

iTrader: (17)

Yes, wide open on the 2 step. I'll see if I can post a log run tonight. Stock 0411 PCM.
No KR through out the run.
The next day I tried playing with the timing while on the 2 step, I found that the 27 degrees I had it at was about the limit before it would start registering KR. Maybe I need to keep the timing higher, for longer.
I plan on pulling the bumper to build a shroud for the intercooler next week, so I'll check for boost leaks then. The turbos are in the fenders, so I can't get to them anyway without the bumper off.

BOOSTAT4500

iTrader: (17)

Yank "power adder" converter. Innovate SCG-1 boost controller.
My IAT's rose from about 110-190 during the run. So I know I need some work there. Ambient was roughly 90 degrees.

BOOSTAT4500

iTrader: (17)

I can't say for sure if the WG is staying closed.
3700 rpm is about all the brakes will hold, so that's my limit there. Might be able to squeeze another 1-200 rpm if I'm lucky, at the track, on a sticky surface.

Forcefed86

iTrader: (4)

IMO you’ll need some way to hold the power back enough to build boost if you every want it to 60’ well. Do you have a line lock to do your burnout? What kind of rear brakes?

I found the soft cheapo pads work best at holding from a standstill, but if you don’t have a line lock you glaze the pads and loose a ton of holding power. The rotors/drums should also have a fresh surface on them. Weld an extension on the brake pedal for more leverage, and literally stand on the bastard. (this helps ALOT) Toss the car in neutral and rev the engine up a few times letting the RPM fall to get a good vac on the brake accum. This with the other changes allowed me almost twice the holding power over my old glazed brake setup. Ended up with a Transbrake on every setup since... It's a night/day difference.

mkvamso

iTrader: (2)

Ive had better luck retarding the timing right around the spool region
Played around with it a bunch and it seemes to work better than advancing it really far
After an afternoon of tinkering with it im able to crack the wastegates at 7-8 psi on the brakes, without a 2step
Before i could only muster 1 or 2 lbs with my foot welded to the floor

BOOSTAT4500

iTrader: (17)

Forcefed- thanks for the suggestions, I'll give them a try. Do you find that pedal extension to be an issue under normal driving? This car is my daily driver, so I don't want it to be dangerous or anything. The rear brakes are Aerospace "drag" brakes. I do have a line lock, but it wouldn't hold the car steady enough so I couldn't use it. Another issue that needs addressing. OEM mustang brakes suck! May have to go to some aftermarkets up front also.

mkvamso- how much timing ended up working best for you? I've always read to advance it with an auto, but maybe that's not working in my situation.

ablakez28

iTrader: (9)

This is a good point to make. Im not sure what dirves this id guess cam/valve events but I have my two turbo cars setup quite differntly to get them into boost. Both though once "lit" are pretty similar. Low timing has worked effectively to get the spool going but I usually end up back at 20-24 once it goes to 2-3psi and taper back out as boost comes in.

Easiest thing to do is start changing the air fuel and timing only in the specific part of the map you are in on your 2-step. Go from there.

Forcefed86

iTrader: (4)

I’m sure it will depend on what kind of room you have and how big your feet are. You wouldn’t need the large flat surface on it. It never bothered me… I always left my foot resting up and well to the LH side of the pedal.

If the pads are aftermarket, they usually require a ton of heat put into them before they get “grabby” I’d run a cheapo soft organic auto parts store pad in back and something like the Hawk HP+ up front. FWD brakes do the majority of the stopping anyway.

Retarding timing takes longer, but adds more heat to the system. Ideally you’ll see the pros run a ton of advance (30-40*+) then as soon at a few lbs are made they drop timing to add tons of heat. If you retard it enough (-15*+) you will leak combustion form the cyls into the hot side (loud popping banging you hear at the drag strip) and it will spool very quickly. I ran -17* to get mine going. But you need a way to ramp timing back in really quickly as soon as you launch which is hard with the factory ECU.

Denmah found that if he forced the 4L80E trans in 3rd gear when on the 2-step he could brake boost a lot more. I believe he used a brake pedal trigger to force the trans solenoids shift to 3rd with the brake depressed. Then when he released the brake it would revert back to 1st and the normal shift pattern.

All that said I’ve used nitrous too and it’s crazy how much of a difference it makes. A 60-80 shot for 2 seconds will light the turbo off quick. A 10lb bottle also lasts a really long time with a small shot only active for a couple seconds. It would fix all your problems and wouldn’t require you to jump through a bunch hoops to get it off the line.

Good luck!

mkvamso

iTrader: (2)

Ive got much smaller turbos than you so they spool fairly quick, around 3k rpm theyre at full tilt. pulling timing at such a low rpm really hurt fuel mileage, and i still drive it on the street quite a bit so i wanted a decent compromise. from 2900ish to about 3100 i think i pulled it down to 8 degrees.

Like mentioned before its probably the heat alone helping spool like that, adding blankets to each turbo and wrapping the hotside has definitely helped it spool quicker as well. Im using an ls6 cam that i had lying around so there isnt much overlap helping to drive the exhaust wheel.

Your setup might like something completely different, but its probably worth a try

BOOSTAT4500

iTrader: (17)

Thanks for the suggestions guys. I'll play around with it tonight and report back.

The entire hot side is wrapped, and each turbo has a blanket as well.

When I smoged it this spring, I had to drop the timing down to the single digits to get it too pass, and I remember the manifolds were glowing by the time the test was over. And that was at much lower rpm's as well. So maybe that will be the key here.
I'm not too worried about what that does to the drivability, as it's easy to have a street and track tune to swap between.

BOOSTAT4500

iTrader: (17)

So I just looked over the log again and it's worse than first reported. I actually launched at 100 kpa, so no boost. I didn't hit 1 psi until 25 mph, and it only got up to 133kpa (4.5 psi) at 54mph before shifting into 2nd. It got up to about 12.5 at the top of 2nd and then held 13.5-14 throughout 3rd gear.

I just went out in the garage and played with it a little. I dropped the timing down to about 9 degrees and the afr into the low 7's, high 6's. I was able to get up to about 117 kpa, a little over 2 psi. This was at 3400 rpm. Painted concrete isn't exactly sticky so I had to drop the rpm a little to keep from spinning. Not earth shattering, but an improvement none the less. I'm sure with the slicks and another 3-400 rpm, a few more pounds should be doable. So that would be 50-100 horse more to launch on, should be noticeable. I'll keep playing with it another day, it was getting a little too hot to continue.

So now my question is, what to do with the timing after the launch. Do I just slowly add more in until I reach the peak of 17 that I'm running? Or once I'm moving, add a bunch back in and then back off as boost builds?

mkvamso

iTrader: (2)

Mine ramps timing back in then starts to pull it towards peak torque amd stays there
The only place its pulled really low is the couple hundred rpm it sees before they're at full boost