I Hate Ricers

Hi, my name is Grant. I am a turbo n00b.

Just wanted to get that off my chest. Ok, well after not having much luck in the 2nd gen forum ( I think most of those guys are NA people..) I think I have found the right place.

My friend just purchased an 88 10thAE (basically an S4 TII). The previous owner installed a 3 inch exhaust from the turbo back, with no cat. MBC is set at 10 psi. For fuel the car has an FD fuel pump (BTW..weren't these supposed to be unreliable...killing many FDs back in the day??) and some sort of fuel cut defensor. HKS filter at the front leading to a stock turbo I believe, then to the stock TMIC.

First off..the MBC was set at 10 psi but the damn thing creeped to 16~17 psi at the top of almost every gear. Not surprisingly, the car smokes as if the turbo is blown but I haven't gone down and checked for end play.

The part that really surprised me, though, is that the turbo FC had little boost before 3.5K...car was almost as much of a dog to drive as an NA. Since the turbo is shot, we're looking to replace it with something that will spool earlier.

So:
Current setup-- builds boost from 3.2K all the way to redline...satisfied with the power (Butt dyno says around 220 hp?).

Looking for-- a whole lot less lag. Looking for boost as early as 2.2K and would like a broad power band, but I understand that it will probably trail off at higher rpm. (Rather have low down torque than peak power...looking for 230 hp...reasonable with the afforementioned mods I think)

What would you guys recommend we look for? Is a ball bearing turbo worth the expense? We are on some sort of budget, so there is a price cap. I read that a T25 on ball bearings will spool really fast. I don't know what kind of A/R or trim I should look for. What do you guys recommend?

Thanks in advance,
Grant

BLUE TII

iTrader: (9)

It was boosting so slowly because the turbo is shot.

When I first got my '87 TII I just had 2.5" downpipe/presilencer, airfilter and TID mod (and fuel and wastegate porting) and it would hit full stock boost ~2,000rpm if I loaded it up in 4th or 5th.

W/ the 3" turbo back the car already has and add a TID mod to this car and it will boost even faster w/ the stock turbo.

If you get the stock turbo rebuilt as a hybrid w/ clipped exhaust and larger compressor it will most likely get full boost ~3,000 to 3,500rpm.

Port the wastegate as large as possible w/ major back cutting add a larger flapper seal to cover the larger WG hole and make sure the flapper doesn't hit the turbo back plate- that will help boost creep a lot.

I Hate Ricers

What is a dead stock S4 TII supposed to start getting full boost at?

So how does the TID mod allow the turbo to spool faster? Ball bearing isn't worth the money huh?

edit: I read that smoke from a bad turbo is only supposed to show itself when the turbo is under load?? The car was smoknig to some degree at idle...maybe we have bigger issues than bad turbo? I hope not... car was running very strong at anyrate...

I Hate Ricers

Hmm...nobody?

RETed

You're dead wrong about not having turbo owners in the FC section...


[QUOTE]My friend just purchased an 88 10thAE (basically an S4 TII). The previous owner installed a 3 inch exhaust from the turbo back, with no cat. MBC is set at 10 psi.[?QUOTE]
How do you know the MBC is "set at 10psi" when you're making more???

The FD3S fuel pump has nothing to do with the fact that the FD3S blows engines.


Again, how can you claim the MBC is set at 10psi when it's making more boost???
If you're making that kinda boost consistently, then I'd bet the compressor carbon seal is chipped.
This is typical when trying to boost the stock turbo over 15psi.
IME, the turbo is just not reliable making boost over 15psi.
Checking end-play will not reveal that the compressor carbon seal is no good.


As BLUE TII said, I agree the turbo is most likely gone.
Fix it first before blaming the car for turbo lag problems.

Tell us...
How much money are you willing to spend?
How much power you're looking to make?
What are you going to use the car for?


-Ted

I Hate Ricers

Hmm Ted..I appreciate the info, but as I said earlier, i'm new at this..not trying to place blame on anyone or anything. Just searching for knowledge.

Couple of things first:
Yeah, of course there are turbo owners in 2nd gen forum. Just most seem to be NA guys, am I wrong?
I read in an article that FDs had fuel delivery issues in their stock configuration, causing many engines to bite the dust. So, if the FD pump really is reliable then so be it, it's only a good thing for us.

The previous owner said he had the MBC set at 10 psi. After turning the MBC all the way down to its lowest setting, it will hold 10 psi for most of the band, then creep to 13psi before redline. Regardless, I'm not worried about the creep as I understand porting will take care of most of it.

How can I check if the compressor carbon seal is good or not then? I've driven another S4 turbo...it was stock and it also wasn't pulling till past 3K. If you guys say that the stock S4s pull from under 3K then I believe you, just hasn't been my experience.

I am still looking for a suggestion. As I stated, we're looking for 230 BHP with a broad power band. I've heard S5 manifold and turbo produce more overall low down torque..should we upgrade to this or spend the extra dough on a hybrid/ball bearing turbo?

I think my friend is willing to spend up to 800 on the turbo alone. I doubt that will get a new ball bearing turbo, but we can certainly shop for used parts.

We intend on practicing low speed drifting in a parking lot with cones. We need the torque going around low speed corners in second gear when shifting to first isn't an option.
Is it something I said? I'm spending time explaining and defending myself but still haven't gotten any good advice/insight/suggestions.

Thanks in advance.

DocMazda

to be honest, if you are going to try your hat at drifting, i would spend that 800 on suspension instead of a turbo. think about it, if you could sustain your higher rpm for a longer duration in a low speed turn before losing grip, then you would be going faster than breaking your tires away early due to higher power to grip ratio. after all, what is the point of trying to get hp gains without first having it sit on the ground first? however, due to your stock turbo probably being blown as it is, it would be a good idea to go ahead and get it upgraded. but, dont think its all about trying to do power-overs in low speed turns, the faster you can enter the corner before the suspension starts to wain, the better you will be in taking those low speed high angle turns. plus, your 230bhp seems to be a good mark to lock-in before you start getting into hardcore suspension upgrades. also, take that p.o.s. stock tmic and go front mount...that will gain you many hp, as well as quicker spool times. often in highly stressing sports such as drifting, you SHOULD be worrying about EFFICIENCY rather than POWER. if you cant get it efficient/steady enough, why worry about how much you are trying to put out there?

Oh well, just my thoughts if it matters...
Ry.

RETed

If you're talking about shear number of threads, it might be biased toward the NA owners...


The FD3S stock fuel pump should be good for 250 to 260hp at the wheels or so.
Most of them upgrade fuel pumps rather quickly.
If the owners are trying to surpass those power levels on the stock fuel pump, then they are asking for trouble.

Most of the FD community used to abide by the mods "rule of 3" - do not change more than 3 things at a time.
I.E. - intake, downpipe, cat-back - OK; intake, downpipe, mid-pipe, cat-back - big no-no.
What it comes down to is the stock ECU is based on MAP sensor based loading.
To the ECU, 10psi is 10psi.
In reality, 10psi is not the same as 10psi with a full exhaust.
In a MAP sensor based loading system, the ECU cannot compensate for changes in engine VE.
When you change the intake or exhaust components, you effectively change the VE of the engine.
This is why most 13B-REW's let go...


With the full exhaust, the MBC is more headaches than it's worth.
I would recommend to pull that thing out and throw it in the trash.


The only way to confirm it is to pull the turbo apart.
Sorry, but this the only way to make sure.
If you pull the intercooler pipes / hoses and find oil, this is a bad sign that the compressor carbon seal is bad.


It's hard to say what "pulling" is...
I'd say my car doesn't really start pulling to 4kRPM, but I'm a bit of a harsh critic.
My car does boost easily under 3kRPM if loaded right - i.e. 4th or 5th gear.


An S5 turbo + manifold is a good upgrade, especially if you're looking to broaden the power band.
The S5 design kicks in at a lower RPM, and transitions a lot smoother.
The S4 tends to give you a kick in the rear end once the boost starts to build enough.

That's not even close to what a full turbo upgrade would require.
Remember, a full turbo will require a front-mount IC, aftermarket BOV, new oil lines, possibly new coolant lines, adapter or custom downpipe, and some kinda fuel control (but full-blown aftermarket stand-alone EMS is highly recommended).

In your case, a compressor upgrade or hybrid might be the answer...


I agree with DocMazda on this - unless you got an upgraded suspension, putting the money toward suspension upgrades would be a better choice.


I think you're not getting good advice cause you're posting in the "wrong" section.
Most of these guys are FD guys, and they don't give a **** about FC's.
You would've gotten more replies if you posted in the 2nd gen section...


-Ted

BLUE TII

iTrader: (9)

I agree w/ TED on all the points.

You had been asking about when the turbo would boost and now you are asking about when it will start "puling".

Big difference between the two on the stock set-up!

My S4 on stock ports/turbo would get full boost VERY quickly, but the powerband still didn't come on untill ~3,000rpm.

Several reasons for this all having to do w/ system Volumetric Efficiency. On the stock S4 set-up the dual scroll actuator keeps all the exhaust going throught the small .40 AR primary path under 2,500rpm so it hits full 6.2psi boost by 2,000rpm (stock high restriction exhaust). Once the 1.0 AR 2ndary exhaust path is opened up after 2,500rpm the VE improves and the car begins to "pull" until exhaust restriction drops boost to 5.4psi by 6,000rpm.

Still, it worked well. at just 1,500rpm the stock S4 TII made 22% more torque than the S4 NA PEAKED at 3,500rpm! and between 1,500rpm and 7,000rpm the torque never dropped below 145ft/lbs.

S5 system where it flows through both exhaust scrolls always actually lost a bit of torque down low, but was better in midrange and top end- not to mention it responds to low restriction exhaust MUCH better giving even more low end than S4 with less boost creep hassles.

The TID mod allows faster spool up as any restriction on the suction side of the turbo really slows boost response. Ditching the AFM (stand alone ECU) or re-locating the AFM to post turbo will also considerably increase boost response.

I Hate Ricers

Hey, the suspension is done. It was already uprated by the previous owner. I'm not looking for much more power either, just altering the power band. What is wrong with the TMIC for relatively low boost driving? How is a FMIC going to help the turbo spool faster? There's more plumbing if anything..

I probably could get away with just clutch kicking around the low speed turns but I'm not a fan of this method for obvious durability reasons.

Ted,
I read that stock FDs had fuel delivery issues after 50K or so miles....if it's not the pump, was it the fuel filter then? I'll take your word for the FC pump being durable enough if that is what you believe.

So I got some good info on your last post. Info on how well the S5 turbo and manifold work is exactly what I was looking for. Also, 800 bucks is for the turbo only, he can spend more on other accessories if it is worth the time and money.

Thanks again.

bcty

The fmic will no be any slower/faster spooling if built nicely..
but practive drifting slower.. rain is always fun to get used to it :P
the stock FD had many problems from the start.. stupid plastic crap.. you are fine with that fuel pump dont worry about it.. Ive seen the pump supply enough for 280rwhp..
If you can get a S5 turbo and manafold for cheep send it off to BNR and get it built up for you. That will help in the power department.
Depends on how much money you are willing to spend. If you really wanna beat on the car and boost much above 10psi I would get a standalone. If not keep it below 10psi and make a nice 3"TID (turbo inlet duct) that will help spool time lots

Tyler