T25... spools to 15psi at 4000?

[curt2go]

Wel I have posted a few other places about this but here is the problem. I hit full boost on a t25 at about 4000 rpms.. That is bad.. It is very sluggish of the line. I mean very sluggish. Compression on average is 158. Tiny boost leak at the TB shaft but still getting the bubbling in the oil on the turblo inlet boost leak test.

I did recently port the t25 mani and o2 sensor housing....

I even blocked of the pcv and same result(It leaks a tiny bit as wee. The new one I bought leaks even more)

Please help.... This now is starting to get madening. i have been chassing little boost leaks but none of them are the culprit. They are all fixed now except for the tb shaft. The boost leak test will get to 20 psi but then slowly go down to 5 psi and stay. Slowlyt meaning about 20 secs to get from 20psi to 5.

Let me know what you guys think. Thanx

 

[oldman]

And for those nay-sayers, yes a bad turbo seal can cause crankcase pressure.

Well I'm one of those nay-sayers, depending on the situation. It's normal for air to pass through the seal during a static test when oil pressure isn't present as long as there are no oil leaks and blowing smoke during operation. Good job both of you for forcing the issue, I'll continue to take the back seat on this one. Please continue....

 

[ddavisaf]

I know you are.
I've seen it before on a damaged turbo. Never before on a turbo with a good bearing and no shaft play though.

 

[oldman]

I know you are.
I've seen it before on a damaged turbo. Never before on a turbo with a good bearing and no shaft play though.

Come over and I'll show you one.

 

[ddavisaf]

Total Est. Time: 28 hours, 4 minutes Total Est. Distance: 1724.10 miles

I'll pass
You know what I meant though... right?

 

[curt2go]

Don't think its the rings cause once I pressure up after the turbo outlet then no crank case pressure. Well a little cause I have not changed the PCV yet. Does that help any?

I do plan to put a 14B in. If I could get one cheap Iwould get it right away. Anyone have one?

There is no smoke from what i can tell when the car is running. Let me know if you guys have more ideas..

Should I leave things for now until the turbo swap or figure it out now so the swap will go smooth? TTY

 

[oldman]

Total Est. Time: 28 hours, 4 minutes Total Est. Distance: 1724.10 miles

I'll pass

I thought you're in the air force.

You know what I meant though... right?

I do, just think that checking for shaft play, oil leakage and smoke out of exhaust are better ways to gauge the health of the turbo than just air leaks during a static pressure test. With that said, after reading through the whole thread again, I'm beginning to wonder if a dying T25 is in play here.

 

[ddavisaf]

It sounds like a classic T-25 to me
Backseat driver...

Yeah, I'm in the AF. What's funny is during work, dsmtuners is more my job than what I wake up at 6 o'clock in the morning for......

 

[curt2go]

In that case any takers on selling their 14B..

PS There is 144000kms on the car. It will make boost very quickly when rolling.

I think I will phone some junk yards today as well.. TTY

 

[curt2go]

I have another Idea. Transmision. I know I brought it up before but no none said anything. I am having surging problems at low rpms around 2000 in 3rd and OD. It will surge about 200 rpms like it trying to find another gear or something. Also in 1st gear from a stand still when i punch it it has no go. So then at about 3000 rpms I let off and the rpms go down to 2000 so the converter is taking 1000 of those rpms.Not sure if that is normal or not So I was thinking maybe converter in conjunction with end clutches or something. This may not be the whole problem but may be also contributing. Just thinking on my ride home.. TTY

 

[doug]

Torque converters rarely go bad. It's more likely that if it's something to do with your transmission that it's one of your clutch packs. That still shouldn't affect spool-up, I wouldn't think, but I'm not sure.

What kind of ATF are you using, and when was your last fluid/filter change?

 

[ddavisaf]

Does this "surge" usually happen when you're taking it easy on the throttle with OD on just after it goes into "cruise mode" If so this is normal. Mine does the same. The best way I know to describe it is econo-mode. It's for better gas mileage.
I don't think you have a problem. In fact, I'm almost certain you don't. At least concerning the transmission.

 

[curt2go]

I have not chnaged the trani fluid since I bought the car. Which was only 4 weeks ago.

As for the surge it does not do it once. I do know what OD is and that is not what it is doing. It keeps surging if I do not get out of that RPM band.

I realize converters rarely go bad but I have seen it. mind you it when you are stalling them all the time but i don't know how the car was driven before I bought it.

It may affect the spool up by it is not puting the propper load on the turbo or something in first gear. Like I said in the past the car is unable to spin the tires even the slightest ON GRAVEL from a dead stop????

I am just throwing things out there. i think I am going to get all new gastkets and bolts on the exhaust side. New tb gaskets and tb shaft seal and a new "working PCV". The spool up to tell you the truth does not boother me near as much as the bottem end having no power. My sprint could peel out in gravel even with 90HP... HELP!!!!

Thanx so far guys I know I will get to the bottom of things with all your help.. TTY

 

[curt2go]

Once again just throwing things out there. What about a bad 02 sensor or very very rich off the line. I am getting a cel now after last week when i took the back 2 bolts off the cat then put them back on and the next day it threw a cel. I have since changed the cat to a hi flo one..

Sorry for going on and on and on . TTY

 

[dsmsucks]

Intake mainfold leak????
How is the cars current condition???(Idle)
My friend was having the same kind problem with his car. His 16g was SOOOOOO lagy is wasnt funny. Hitting full boost at 4500rpms
Do another leak test and listen around the manifold
Hope this helps

 

[curt2go]

The only one around the mani is the tb leak but it is not big at all. The onjectors leak until the engine is warm but thats all. Maybe a gasket leak on the runners at the bottom ?? To be a boost leak problem I think it has to be a big leak or a lot of samll leaks but there is only a couple very small ones left. From what I can tell.. TTY

Oops I dle is very good. No surging steady at about 700 rpms.. TTY

 

[1gnasty]

check for boost leak's and check the actuator

 

[doug]

check for boost leak's and check the actuator

Didn't bother to read the rest of the thread at all, didja?

 

[doug]

Once again just throwing things out there. What about a bad 02 sensor or very very rich off the line.

No. If anything, running rich will spool the turbo faster.

My gut feel tells me it's not tranny-related. But since you don't know when the fluid was changed last, if I were you I'd change it anyway. You can do it yourself; it's easy. There's a VFAQ at plymouthlaser.com if you need one. For ATF, I like either synth TrickShift (although a few guys claim it expands seals too much) or Mobil 1 Dexron III with a bottle of black LubeGard added. Change the filter/gasket while you're at it. You can get a filter/gasket kit at Pep Boys or Discount Auto Parts or wherever.

You did use a spray bottle with some soapy water in it, correct? Sometimes leaks aren't audible.

 

[curt2go]

I used soapy water only around the tb to pin point that leak. I guess i should have done it everywhere. As for the trani fluid. I was just waiting to change it all when I did the shift kit change and put in new end clutches.. TTY

 

[doug]

You can wait if you want. However, you can change the end clutch without having to drain the fluid, if you decide to do that.

 

[91Bomb]

Also as I have siad before it is very sluggish of the line. It willnot even spin in gravel. If that helps pin point anything?

Off the line without power braking these cars have absolutely nothing -- a Civic or Corolla has more punch from a standstill. It is the nature of these cars. A small engine with Low compression are only 2 of the factors that contribute to this. Normal = turbo lag and then the car takes off. I had a '91 TSI A/T that was significantly lighter in weight to your 2g, had a smaller turbo (13g), different cams from yours to help the low/mid end, and off the line it had absolutely nothing! With A/T DSM's you either brake boost -or- you be courteous and give the other guy a head start
BTW, I don't think my 1g could spin tires in gravel either -- at least not in any SELF-RESPECTING gravel

I don't think the tranny is slipping but it is surging a little at low rpms in 3rd and OD..

CHECK YOUR TPS. Check your throttle plate and make sure it operates properly. Pull trans trouble codes. After that you might want to have your trans + T/C checked -- try to find a DSM shop or someplace you can trust so you don't get stuck with some unnecessary work being done.

A STOCK 4 cyl turbo is not at its best with an A/T. Maybe on a big 6 cyl or 8 cyl it would be fine. You also have 1 less gear than the M/T model along with some added weight. Motortrend has a 2g A/T turbo FWD running a 15.5 sec 1/4 mi @ 90.3 mph vs a 14.8 @ 91.xx for a GSX M/T. That was with brake boosting -- without it the 1/4 would've been laughable.

 

[91Bomb]

A STOCK 4 cyl turbo is not at its best with an A/T. Maybe on a big 6 cyl or 8 cyl it would be fine. You also have 1 less gear than the M/T model along with some added weight. Motortrend has a 2g A/T turbo FWD running a 15.5 sec 1/4 mi @ 90.3 mph vs a 14.8 @ 91.xx for a GSX M/T. That was with brake boosting -- without it the 1/4 would've been laughable.

OK, that is my quote, is that wrong to do?

I see in your case you are not stock, you are much better because you're running 15 lbs and have a high-flow cat. Do you have a K+N w/ hacked airbox? A DP? Perform all basic tune-up procedures before boosting to 15 lbs? How are those plugs + wires? fuel filter? Trans filter?

*edit*
You mentioned you're new to DSMs. Make sure you do the suggested upgrades with that added boost you're running -- extremely critical! Which ones and why? Don't hesitate to ask or do simple research to find out.

 

[91Bomb]

Just realized you have AWD. 3100+ lbs ? The added weight over a FWD A/T alone hurts you and putting power to 4 wheels vs 2 off the line (without brake boosting) hurts some more.

If you plan on going the 'cheap upgrade' path -- ie, keeping 450 injectors + max boost of 15 lbs -- you might want to look into a S16g, full exhaust and the like if you expect anything decent out of your 2g AWD A/T. Of course you can turn your car into a monster if you have the time and money but do some research first.

Personally I prefer 2WD with the A/T when going the 'cheap upgrade' route because of the weight savings and the fact that traction isn't as important at lower HP levels.

 

[curt2go]

Man thanx for the input. Greatly appreciated. I have done all the upgrades. i have ak&n with no airbox. Juts the filter. Done the fuel pump rewire. I would not get anyone to look at my car at least not a shop . I do all the work myself. I have build chevy race motors for drag cars but they are quite different from these. So it will take a little time to get used to...

I plan to get a 14B port and polish it and get full exhaust as well. Very soon. Well at least the exhaust.

I still have some tinkering to do for sure but it is comming. I have to get everything sealed with no leaks at least then I have a base line. I think i iwll order the shift kit and end clutches very soon and get that stuff changed..

Thanx for the info again everyone.. TTY

PS Keep the thoughts comming if there is anymore.. TTY

 

[91Bomb]

Your mods profile doesn't list a DP
I'd be very wary about running 15 lbs without one as it is VERY restrictive.

When upping the boost above stock you basically should have AT LEAST a DP + testpipe or high-flow cat, K+N with modded airbox, real boost gauge + egt gauge, and FP re-wire. AND prior to any of that all BASIC MAINTENANCE should be performed along with boost leak testing, a standard compression test, cheking of base timing, basic trans service, and all things along those lines.

DSM's have strong motors + the A/T's are strong too. Even high mileage 4g63t's are often found to be in very strong shape but that can and is too often undermined when the boost is turned up and the car isn't primed for it and/or you don't have a real boost gauge and EGT to keep an eye out for impending problems.