# Other turbo problems



## aminidab (Apr 30, 2002)

I'm having some problems with my turbo setup, nothing major but it's getting hotter than I think it should and not running as fast as it should. 

My setup is a GA16DE HS kit w/DP turbo, 370CC injectors and 240sx MAF

I checked for boost leaks a few weeks ago, found some and fixed them. It's been running better since then, but the turbo is still not spooling up as fast as it was on my other engine. This weekend I plan to do a compression test, check timing & idle, and check for boost leaks again, is there anything else I should do?
One of the leaks I found but couldn't fix last time was a minor one around where the EGR goes into the intake plenum. Is there a gasket for this? I didn't see one listed in the FSM. 
Also there are a couple of other problems I'm having. 

The first thing is the EGTs, if I'm not careful they can get above 1450, and they've gotten as high as 1500 once or twice. At 1500 I've been letting off so as not to melt anything, but if I kept going they would go above 1500. Anyone know why they would be getting this high at 11 PSI? 

Another problem I'm having, oil pressure at idle. When the car is hot the oil pressure drops as low as ~6PSI at idle. My thought on this is the oil is getting too hot and getting thin, but I don't have an oil temp gauge to check this. I'm currently running 10w30, should I try another weight?


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## Chuck (Nov 19, 2003)

5W 30 can transfer faster dude.. and it woudlnt hurt to use synthetic.. it can withstand heat better.. man, its very strange.. maybe you should consider water injection. cool down the cylanders a bit.. im actually shocked that you are running that high.. i wonder if somehow the discopotato heats things up?.. im not sure if a turbocharger would have anythign to effect the heat of the exhaust.. i mean.. different styles of turbos.. im thinking maybe the oil pump is going out possibly?.. or the pressure sending unit is just trippin.


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## chimmike (Oct 17, 2002)

eliminate the EGR!!! also, what size is your IC, and if you're running the GT28RS.....maybe you're creating more pressure in the exhaust manifold which would increase temps.............

generally if you had a boost leak you'd definitely be able to tell. my personal opinion is that the GT28RS is too big for a stock GA16.....but that's just my opinion.


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## aminidab (Apr 30, 2002)

The oil I'm using in synthetic, Mobil 1. I have thought about adding water injection, but then I have to get my ECU reprogrammed and I don't have an ECU to swap out for the injectors/MAF. Wierd thing is I'm running most of the same parts from the oil pump out of my old engine and I didn't have the pressure problem.

I haven't measured my intercooler, but it is fairly large(that's real helpful, I know). I was actually thinking of cutting a bit more of the bumper to get more air to it, but that's probably overkill. I'll take some pics and get a measurement tommorrow.

I'd love to get rid of the EGR, but in the end it seems like it'd be more trouble than it's worth.

Chimmike, why do you think a GT28RS is too large for a GA16? unless maybe you think any T28 is too big for a GA16.


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## James (Apr 29, 2002)

The egr tube has a small gasket... its part # 14719+A

Is there any leaks between the manifold and the turbo?


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## aminidab (Apr 30, 2002)

James said:


> The egr tube has a small gasket... its part # 14719+A
> 
> Is there any leaks between the manifold and the turbo?


Cool thanks for the part # James! I don't think there are any leaks there, but I'm going to check that this weekend. I put lock washers on this time because the nuts came loose on me last time.


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## James (Apr 29, 2002)

No prob. 

Hey if you reused the oil pump from your old engine maybe the pressure regulator needs to be shimmed up?


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## lshadoff (Nov 26, 2002)

You may be maxing out the 370 injectors at 11 psi. Then it runs lean when approaching max power and the EGT goes ballistic.

Do you have a Walbro 255 (or equivelent) fuel pump? The stock pump is not capable of 11 psi. I blew the electrodes off two spark plugs at 6.5 psi.  

Lew


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## aminidab (Apr 30, 2002)

lshadoff said:


> You may be maxing out the 370 injectors at 11 psi. Then it runs lean when approaching max power and the EGT goes ballistic.
> 
> Do you have a Walbro 255 (or equivelent) fuel pump? The stock pump is not capable of 11 psi. I blew the electrodes off two spark plugs at 6.5 psi.
> 
> Lew


I didn't mention this in the original post, but I have a GA16. I should be ok with setup at 11PSI as wes and myoung have boosted beyond 14 PSI and been ok.


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## James (Apr 29, 2002)

yea I was thinking that too but you have the DP turbo, which may flow more than the T28 at that psi.


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## aminidab (Apr 30, 2002)

James said:


> yea I was thinking that too but you have the DP turbo, which may flow more than the T28 at that psi.


I've thought about that too and I figure measuring the MAF voltage would be a good way to check where I'm at. I ghetto rigged up a way to check it too... I tapped into the MAF wire on the ecu. Now I just need to find a willing passenger to read a voltmeter between that and a ground 

Man I need a Techtom


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## James (Apr 29, 2002)

Tape someone to the hood...


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## chimmike (Oct 17, 2002)

aminidab said:


> I didn't mention this in the original post, but I have a GA16. I should be ok with setup at 11PSI as wes and myoung have boosted beyond 14 PSI and been ok.



you can't compare a turbo that makes up to 250-280whp to a turbo that makes up to 320+whp.............at the same psi the GT28RS flows more air..................requires more fuel......c'mon bro, you should know this 
try turning the boost down to 7psi and see what it does

I think the GT28RS is too much turbo for a GA16 in my opinion because it can probably flow more air than the engine can handle. 

My personal opinion is it's not smart to use a turbo on a car that a simple spike in boost could cause it to throw a rod or something.


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## morepower2 (Apr 19, 2002)

aminidab said:


> I'm having some problems with my turbo setup, nothing major but it's getting hotter than I think it should and not running as fast as it should.
> 
> My setup is a GA16DE HS kit w/DP turbo, 370CC injectors and 240sx MAF
> 
> ...


Are you exceeding 5.1 volts from the MAF? If so you are out of injector. The DP is a real effient turbo and you coulkd be maxing out your injectors and running lean.

Mike


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## aminidab (Apr 30, 2002)

chimmike said:


> you can't compare a turbo that makes up to 250-280whp to a turbo that makes up to 320+whp.............at the same psi the GT28RS flows more air..................requires more fuel......c'mon bro, you should know this
> try turning the boost down to 7psi and see what it does
> 
> I think the GT28RS is too much turbo for a GA16 in my opinion because it can probably flow more air than the engine can handle.
> ...


I agree that it's not a good idea to be running at that level of boost for a daily driver when pushing it too hard could blow the engine. I'm probably going to get a different WG spring to set the max PSI lower for daily driving and get a boost controller so I can slowly increase the boost.

I was thinking it was a possiblity that the EGTs were high because I had maxed out the injectors and was running lean, but I didn't think it was too likely just b/c that would be putting out a lot more power that I thought I was. 
Since everyone seems to think there is a good chance this is causing the problem, I'm going to check the MAF voltage as soon as possible. So I just need to find a willing passenger, who despite what James thinks, can ride inside the car


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## wes (Apr 30, 2002)

I agree that you are probably maxing out the MAF or injectors at that PSI given the efficency of the DP turbo. You really need to monitor MAF voltage. My car was hitting 5.11 volts at like 12 PSI on the T28 however even at 13-14 PSI it was getting to about 1450 on LOOOONG pulls. The coatings are helping me there though. 

Turn the boost down and monitor MAF voltage. Also when are you making full boost? I was hitting 14 PSI at about 4K on my setup. With boost building at 2300 rpm's. This is with a 3" cat back. 

FYI 7 PSI is the factory spec. for oil pressure at idle. Mine stays around 7-11 PSI.


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## aminidab (Apr 30, 2002)

wes said:


> I agree that you are probably maxing out the MAF or injectors at that PSI given the efficency of the DP turbo. You really need to monitor MAF voltage. My car was hitting 5.11 volts at like 12 PSI on the T28 however even at 13-14 PSI it was getting to about 1450 on LOOOONG pulls. The coatings are helping me there though.
> 
> Turn the boost down and monitor MAF voltage. Also when are you making full boost? I was hitting 14 PSI at about 4K on my setup. With boost building at 2300 rpm's. This is with a 3" cat back.
> 
> FYI 7 PSI is the factory spec. for oil pressure at idle. Mine stays around 7-11 PSI.


I'm not sure exactly where I'm hitting full boost, at this point I've been watching the EGTs closer than the tach/boost gauge, but it's around 5K rpms. Previously I was getting full boost at around 4.5K, and I believe that was with some boost leaks.
In my car it's all too easy to get the EGTs to 1450, driving hard in 3rd or above and it gets there all too easy.
I checked for boost leaks again today, and I didn't find any major ones. There is a minor leak right after the turbo that I wasn't completely able to fix but it's very small at this point. At 8 PSI I could just barely feel it. I also checked the timing and it's right at 10. 
I did a compression test too. 
The results were 160 170 165 170. 
After adding oil the results were 185 200 185 205. 


I was not able to monitor the MAF voltage today, but I should be able to do that next week. I figure getting it dynoed might also help diagnose some problems, but I was hoping to do that after I get everything running right.


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## wes (Apr 30, 2002)

That seems aweful high for the potato to spool on our engine. It's making full boost in the 2900-3200 range on 1.8 miata's and SR20's. I wouldn't think it would be a slower spooler than the T28. I am going to extrude hone my DP turbine housing when I get it to see what that does. 

1450 is not horrible, could get hotter. 

What is your exhaust setup?


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## aminidab (Apr 30, 2002)

wes said:


> That seems aweful high for the potato to spool on our engine. It's making full boost in the 2900-3200 range on 1.8 miata's and SR20's. I wouldn't think it would be a slower spooler than the T28. I am going to extrude hone my DP turbine housing when I get it to see what that does.
> 
> 1450 is not horrible, could get hotter.
> 
> What is your exhaust setup?


I realize that's really high, that part of my question here. I don't understand why it's taking so long to spool. 
I'm running a 2" mandrel bent cat back.

The problem is 1450 comes very early. If I'm on a long pull it comes very quickly, the only reason it dosen't go higher is b/c I let off. As I said before the EGTs have hit 1500 once or twice when I wasen't careful, they could easily go much higher. This is almost certainly what lead to the early demise of my first engine.


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## wes (Apr 30, 2002)

aminidab said:


> I realize that's really high, that part of my question here. I don't understand why it's taking so long to spool.
> I'm running a 2" mandrel bent cat back.
> 
> The problem is 1450 comes very early. If I'm on a long pull it comes very quickly, the only reason it dosen't go higher is b/c I let off. As I said before the EGTs have hit 1500 once or twice when I wasen't careful, they could easily go much higher. This is almost certainly what lead to the early demise of my first engine.


Take off the exhaust after the cat and see how it runs. Do it tomorrow I am very curious...


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## James (Apr 29, 2002)

aminidab said:


> I'm running a 2" mandrel bent cat back.


 :jawdrop: 

Backpressure... MUCH!?!? I think that's the cause of your high EGT...


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## aminidab (Apr 30, 2002)

wes said:


> Take off the exhaust after the cat and see how it runs. Do it tomorrow I am very curious...


That's a tall order to fill, not sure I'll be able to do that tomorrow. But if I get a chance I'll let you know how it runs.


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## wes (Apr 30, 2002)

aminidab said:


> That's a tall order to fill, not sure I'll be able to do that tomorrow. But if I get a chance I'll let you know how it runs.


HAHA I didn;t expect that but I suspect that is going to change a lot of things, your EGT's for one!


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## javierb14 (Jul 9, 2002)

an open downpipe will make a *huge* difference....especially when compared to a 2.0 catback. example, take a look at how much more power my buddy made with a open downpipe compared to a 2.25 in. catback

-closed cutout was about 11~12psi
-open cutout was about 14 psi
dyno plot


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## aminidab (Apr 30, 2002)

javierb14 said:


> an open downpipe will make a *huge* difference....especially when compared to a 2.0 catback. example, take a look at how much more power my buddy made with a open downpipe compared to a 2.25 in. catback
> 
> -closed cutout was about 11~12psi
> -open cutout was about 14 psi
> dyno plot


damn that IS a huge difference! 

If it made that much a difference on my car, the EGTs might drop b/c of lower backpressure but shoot up b/c it was running lean. If I'm not maxing out the injectors at 11 psi, I almost certainly would be at 14.

I was thinking today that the high EGTs can't be because the injectors are maxed out, at least not entirely. When I'm driving on the freeway at 75 the EGTs will get as high as 1400, and this is w/o driving hard and w/o spooling up the turbo in the last 5 minutes or so.


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## James (Apr 29, 2002)

I may be wrong but high EGT's doesn't always point the finger at running lean. For now we can't be sure its your injectors but we know for sure that the 2" exhaust is more of a probable cause!


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