Shooting for 11's stock turbo, can't get the car to go faster......

D

DougsfastZ

4.1
Joined
Jan 30, 2004
So my goal this year is to get the car to go 11's on the stock turbo and intercooler (no Dutt neck) on 93 octane with meth. The main mods to the car are in the sig. I was able to go 12.17 @ 109 with a 1.69 short a few weeks back in mid 60 degree weather. Just this past Saturday, I was able to get 12 passes in and match my 12.17 pass twice, once with a 1.67 and one with a 1.66 short, both at 110 mph. The weather was hot though, high 80's (DA was at 17xx). I was able to tune the car with the MAF Pro to get the car to run 110 mph 6 times in a row. That is a good sign, I was able to gain a mph with tuning in much hotter (and humid weather).

The issue is I couldn't tune the car to get any faster, over those 6 passes I slowly took out fuel and raised timing, and ended up pulling 15% fuel and raising my timing from 25 to 27 degrees (1st and 2nd gear, pulls 2 degrees in third), and the car wouldn't MPH (or ET) any better. I did notice in the Powerlogger that the motor was seeing about 200 degrees in the up pipe (where as in 60 degree weather, it was seeing 175 degrees or so) before the Meth nozzle. I had 0 knock all day. I started my boost at 22 psi, and went to 23 psi, but didn't go any higher in fear of running out of the turbo's inefficiency.

My question is, what could my "brick wall" be? I've had real good luck with the MAF Pro and being able to tune the car to get faster and faster. Do you think the heat would cause the car to stop getting faster? Anything I may be missing?


Thanks,

Doug D
 
How much boost are you running? I see you have 22 in your sig.
You need to run ALOT with a stock turbo to have real good et`s.

And a better 60 like Sean mentioned.
 
I was launching between 10 -12 psi. The car was hooking great all day, and the lower control arm relocation brackets really kept the car from squating like it did before. BTW, Hydroboost brakes are amazing. I don't feel I could build any more boost on the line. How much psi can guys launch at on the foot brake?

I started at 22 psi and set it 23, and thats where most of my 110 mph runs were set at. I was afraid to go higher since I read here that the stock turbo is less efficient over 23 psi.

Thanks,

Doug D
 
I think you've hit the wall that most people get to when running a stock turbo setup. At this point, you can usually only do a few things.... lighten the car, run more boost, or lower the 60ft. Lightening the car may take money for some things, labor for others, and deceased comfort for others (removing sound deadening material for example). Adding more boost will increase the chance of breaking something and there is diminishing return for running high boost on a stocker, but it should lower the ETs a little. Decreasing the 60ft will take time and effort. Moving to a transbrake setup is probably the best bet, but again it takes money.
 
You need to modify your stock parts. Port throttle body and bell it. Do the conversion to remove one of the mounts on the throttle body so it is flat on one side. Port your plenum. That should help out.

Another is port your stock headers and remove all of the overlap sheeting inside of them so everything is smooth.

I know a guy who runs 11's with these mods and everything is stock. Im sure I am forgetting some stuff, but hopefully this helps. Hopefuly this isnt a secret. sorry if it is.:confused:
 
I didn't want to lighten the car at all, that's part of the goal, full weight (down to the spare tire and stock wheels).

The motor right now is stock other then a power plate and 100 lb valve springs. Maybe it's time to clean up some the stock parts. Just got a couple of carbide burs that could use some breaking in :)

Doug D
 
Hi,
By reading your posts,I have come to the conclusion that no way in hell am I gonna hit my goal of 11.99 with my present configuration. As a result, I have rescaled my goal to 12.5. I figure it will still be a scary street car,able to eat loads of rice on demand. Good luck with the challenges that come with 11 second ETs!
Dale
 
85HOT-T said:
Be careful thats an easy way to toast a converter clutch.
Click to expand...

NO IT ISN'T :rolleyes: doin that since 1987 with the good ol stock D5s running mid 11s in my fleet of cars .. Ya I do have a tranny cooler and a switch at my fingertip :p oh 110 mph is not maxed out :cool:
 
Modify Stock Parts

If you have not already you need to port and polish your stock compressor housing (cold Side) and port and polish the exhaust elbow. Also do the same on the intercooler inlet and outlet and throttle body . You could put some lighter wheels and tires and aluminum rear drums , that will lighten up your rotating weight some. Those mods should shave a few tenths off. Also a 2800 stall would help your 60 ft.
 
Grumpy said:
NO IT ISN'T :rolleyes: doin that since 1987 with the good ol stock D5s running mid 11s in my fleet of cars .. Ya I do have a tranny cooler and a switch at my fingertip :p oh 110 mph is not maxed out :cool:
Click to expand...

really? what would make a converter not lock up at WOT but locks perfectly on the highway just cruising?
 
IMHO.... work on your 60'......then when you get done.... work on it some more....

You are leaving .15 in the 60' on the table.... that is an easy .25-.3 in the 1/4..... YMMV....

Ed Brewer went 1.50 in the 60' on his way to an 11.37 with the stock turbo... His car was a lightweight T if there is such a thing.... and a orange stripe converter I think....

IMHO all you need is decent air... and a good 60' and you'll bust into the 11's easily.

As far as boost level.... you can try it... it heats the air up alot... but I think Eddie ran upper 20's in 1st and second.... and it would fall back to 23-25 psi or so in high (only because it just wouldn't make any more boost)..... anyway.... he ran more than 23....


You mention relocating your control arms.... any particular reason? Did the relocating of them help the 60' time any?

Hopefully you can sneak up on a better 60' time... and consequently the 11 sec slip you are after....
 
Id let the boost go up quite a bit more in first gear. 26-27psi in first. It will 60 better even though theoretically its out of the compressor efficiency range. Work on suspension and maybe put in a t-brake. You should be able to get 60's in the high 1.50's. Run 23-24 psi and keep increasing the methanol flow and pulling back the injectors. You need to use a lot of meth if you want mph with the stock turbo. Put the car on a diet. I ran as much as 32 degrees advance with c16 and meth at 23-24 psi with the stock turbo.
 
Blazer406 said:
As far as boost level.... you can try it... it heats the air up alot... but I think Eddie ran upper 20's in 1st and second.... and it would fall back to 23-25 psi or so in high (only because it just wouldn't make any more boost)..... anyway.... he ran more than 23....
Click to expand...

Lol! I never even read your post before posting. I forgot to mention all i had back then was a Scanmaster 2.0. Nothing like whats out there today.
 
If you do all of this porting, etc and it makes a difference, the result you will see is more boost for the same wastegate setting. If you then turn down your boost back to where it was, you'd still be making roughly the same power. You'll still have to flow more air into the engine to make more power. If everything is ported, your turbo doesn't have to work as hard though. But with Meth, the air gets cooled anyway.

Your single biggest restriction is probably the stock IC. I'd put a dutt neck on it before worrying about the plenum, throttle body, etc. I'd assume you already have a power plate.

Your 60ft is already darn good for a stocker. My experience and watching others is that to get deep into the 1.6s or into the 1.5s, you'll have to do a lot of suspension tuning and tweaking until its dialed in perfect or go to a transbrake.

I wouldn't worry about wear on the converter. Should last a while and replace it if it wears out. You need to lock it to get the good ETs and mph on a stocker.

I think the mph is great for a stock setup with a stock IC. You've already got a lot of parts already that aren't stock anyway, so I don't see how removing some weight to guarantee an 11 will matter. I think keeping the stock IC, turbo, throttle body, and plenum would be more impressive.
 
Wow not bad at all! Like other said, IF you do decide to change anything else I would go straight for the dutt neck or a good intercooler.

IMO you already replaced the down pipe... Why not replace the IC neck? At your current level you will most likely see 2-3lbs boost difference when swapping the necks...

You're going to have to do A LOT of work to get much lower with your setup as it is sits right now... there are a lot of flow restrictions, that if removed would make one hell of a difference... You can do all of the porting, but it's going to be a lot of work.
 
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