So here's the deal...

I just finished breaking my rebuilt S5 TII engine in (1500 miles), and am ready to make some power . The car is a 1990 TII with a 3" straight through exhaust -- no cats and a borla XR-1 as a muffler (pretty much a straight pipe). Right now i have the stock airbox on it, and the turbo (from a j-spec) feels like it has a lot of play. I'm running everything with a Haltech, and AFR is ~11-12 under boost (it's still pretty rough, but it looks safe to me).

1st gear only makes about 5psi of boost, and second and third gears will only pull about 6psi. The most i was ever able to hit was 9psi going up hill in 4th, floored at 100mph... it just won't boost! Today in 2nd I did a couple 30-50 runs (floored at 20, started the watch at 30, etc.) and got 2.65 seconds... that's about what a stock TII should run! Does this seem right for what I'm running? How much of a difference will a 3" TID and cone filter make? I've got a walbro and FMIC ready to go into the car, so i'd like to get that boost up to at least 8-9 psi!

Thanks!,
Manolis

 

If that fmic is big.. you're gonna get a decent amount of lag IMO. Sounds like your turbo is mighty fuxored.

 

That FMIC isn't in there yet , so that shouldn't be affecting boost yet! How much boost will a stock TII pull in all of its gears?

 

I could only hit 9 with a RB exhuast and stock intake. it wasn't too hard to hit it though. wot in 4th any time.

 

Do you know how much boost you could get in the other gears scott? I'll go see what my car can hit in 4th tomorrow. In the time being, does anybody have 30-50 times for their TII's (modded or not)? if possible, floor it at 20 and start / stop the watch at 30/50

Thanks,
Manolis

 

it would hit 5/6 in first and 7/8 in 3rd

 

I have the exact same problem buy a cheap MBC and get all the boost you want like a Turbo XS type-s, check out my " How much boost" thread

 

thread is on pg.5 I believe

 

Scott: Thanks for the numbers! Maybe mine isn't all that far off...

NRA T2: Thanks for the thread! I may just end up doing that.

Now... about them 30-50 times... I think i'll start another thread asking for them, just to see what people come up with.

 

Get a cone intake and 3" TID and watch the boost soar

 

Manolis, ive got a 3" all the way back exhaust as well, with a TID and cone filter. Ive got a walbro fuel pump, with 720 secondaries and an S-AFC for my fuel. I hit about 6 lbs in first, 8-9 lbs in second, 12 in third, and 12-13 in fourth. I am still running pig rich, so I am not incredibly worried about detonation at this point. my Greddy EGT shows about 730C at WOT in fourth, still plenty of breathing room. Yes, I am aware that I am right at the peak of the turbo's efficiency range, and it will not last an incredible length of time the way I am running it right now. I plan on getting it rebuilt with maybe a few upgraded goodies, so don't flame .

If I were you, i would drop in that walbro before you try to boost any more, just for safety's sake. If you haven't done the fuel pump rewire, I would think about doing that as well to make sure you have full voltage at your fuel pump. IF AND ONLY IF you have the fuel to go with the extra boost, you might want to think about getting rid of the stock airbox and going with a conical intake filter, and maybe a TID.

Jameson

 

I've got a cone and I still have the problem, sorry for the ignorance but what does TID stand for

 

umm
do you get any turbo flutter


my suggestion is buy a high flowed stock on or upgrade
to something big name like hks garrat blitz

 

my turbo works great, responds, makes up to 15 psi, makes no unusual noise and was recently rebuilt

 

TID=turbo inlet duct

Its the black tube that goes from the AFM(air flow meter ) to the turbo. They tend to crack and leak and alot of times you can't see it. Plus they are a bad design and a custom TID will work much better. Do a search for "TID mod."

 

TID stands for "turbo inlet duct". The stock one is the black piece that more often than not, has a crack on the turbo side. this causes all sorts of idle and boost problems. Replacing it with a "tube" of some sort allows for less restriction on airflow, and quicker turbo spool up. my TID increased my boost by 2 psi.

I have a manderal bent tube with a 3-2.5" reducer on the end. My stock boost control line is plugged, and there is a spot for the PCV to go into the TID. I am getting rid of this soon, and going with a catch can so I dont dirty up my Throttle body and intake manifold

Jameson
Jameson

 

I have an aftermarket TID also

 

I used to have a 89 turbo II with intake and a 2.5 inch downpipe mid-pipe and stock y-pipe and I was hitting 6psi in first 8-9 psi in 2nd gear 11-12 psi in 3rd on a very cold night and thats above sea level where I live. So what I'm saying is there is something wrong with the way your s5 its tuned.

 

I used to have a 89 turbo II with intake and a 2.5 inch downpipe mid-pipe and stock y-pipe and I was hitting 6psi in first 8-9 psi in 2nd gear 11-12 psi in 3rd on a very cold night and thats above sea level where I live. So what I'm saying is there is something wrong with the way your s5 its tuned.

 

like what?????

 

Let me get this straight. You have a Haltech on the motor and running a stock airbox? How so? The map sensor eliminates the MAF.

*IF* you have a Haltech in the car, then you should be able to get more than 5psi with no boost controller. You may have a leak somewhere.

-M

 

First of all, thanks for all the responses. Now...
Thanks for the numbers everyone. I'm pretty sure there's something wrong with my turbo after looking at all this stuff. I know that it has quite a bit of play, but aside from that the thing only makes 4.5 psi in first (at least to 6000 rpm), then 5.5 in second, and (if i'm lucky) 6.5 psi in third (all to 6000 rpm for the moment). supposing my turbo is 'fried', how much of a difference would that make? I did some calculations today, and ended up with an average of ~150 ft lbs of torque between 30 and 50 mph --obviously waayyyy too low. Granted, these were pretty basic calculations, but they should be relatively close. If anybody wants, i can post the calcs. for you to double check!

TBoost: The stock airbox will be coming off very soon -- in a couple of weeks. I just wanted to get past smog with as little fuss as possible, and that thing looks stock under the hood right now

The only causes for the 'slowness' () i can think of are as follows:

1). 'Fried' turbo
2). old / shitty spark plugs (will be replacing this week! How much of a diff. will this make?
3). running no OMP and 128:1 premix ratio (I think that should be OK)
4). High intake temps (no less than 65C / 150F and up to 85C / 180F or so)
5). stock airbox and PVC "TID"

Everything else should be more or less in line I think. One more thing -- I was coming up a hill near my house tonight and floored it in second and it seemed to be a lot faster than it had been all day (I think), but then i did it again and it seemed back to 'normal' (read: slower than shyte!)

Anyway, i'd really like to get this sorted out soon -- it's maddening to know there's sooo much more you can get out of your car by just fixing it!

Thanks!,
Manolis

Going crazy in TII 'ville!

 

Man its crazy. I had a low boost problem before. I did absolutely nothing and one day I floored it and I was like "wow!" I hoped forever it wouldn't go back to the low boost again and it never did. My car has been down for a few months and I've been worried it might be back to the low boost These cars got a mind of their own.

 

I have a 89 t2 :

Apexi Intake
RB full 3" exhaust
Apexi ACV-R

The ACV-R can monitor throttle position. I have it set to .8 bar (approx 12 psi.) and I can hit and hold a steady .8 bar starting at 3000 to 3500 rpm with 35% throttle. I know I could set it higher if I wanted to but dont want to risk the wear and tear.

Make sure you dont have a leak in your inlet system. Check the intercooler to Intake manifold. Check the rubber pressure line that goes to pressure sensor.

 

Manolis-D:

How do you have the Haltech system hooked up? Also, if your turbo was fried (which it very well could be), you'd see smoke but boost pressure would be achievable in a damaged seal condition. If the compressor wheel is hard to turn by hand, then your journals have stiffened and that is the cause of the low boost. If neither of the two are happening, then I can't see how the turbo is bad.

If you give me some info on your setup and what lines are going where (with the Haltech), I can give you some pointers. I also have been using a Haltech for months now (and also had a new engine change this year).

-M