Turbo lag/boost problems. Help please????

[AZ88Turbo]

Hi All,

I just had my turbo rebuilt and it still isn’t right. It is acting almost the same way as it was before it went out (died). The boost doesn’t come in until around 3500 rpm (used to come in around 2500) and then comes in really slow. I had the compressor wheel upgraded to a super 60 and expected a bit more lag but I didn’t expect it to act like this; and because it is acting like it did before I had it rebuilt; I have to think it is something else. Wastegate perhaps?

Any help would be much appreciated.

Thanks,

Mark – 88 Turbo

[lotusguy]

AZ88Turbo said:

Hi All, I just had my turbo rebuilt and it still isn’t right. It is acting almost the same way as it was before it went out (died). The boost doesn’t come in until around 3500 rpm (used to come in around 2500) and then comes in really slow. I had the compressor wheel upgraded to a super 60 and expected a bit more lag but I didn’t expect it to act like this; and because it is acting like it did before I had it rebuilt; I have to think it is something else. Wastegate perhaps? Any help would be much appreciated. Thanks, Mark – 88 Turbo

Mark,

Check the obvious, leaks from the exhaust, leaky wastegate actuator etc. Also, could your cat be obstructed/collapsed? Another somewhat rare occurance is the collapse of the air trunking hose from the airbox. These are multi-lam hoses and have been known to de-lam and totally/partially collapse inside resticting the airflow, this could mask itself into a poor performing, excessive lag turbo. Hope this helps. Happy Motoring!... Jim'85TE

[AZ88Turbo]

Thanks for your help Jim.

Couple of questions: How can I tell if the wastegate actuater is leaking? Would I be able to feel exessive movement when the wastegate housing is off? How would I tell if the CAT was damaged? Thinking about it; the guy who rebuilt my turbo said to check my cat as it looked as though heat had damaged the bearing or something. I just got through emissions in January so maybe I should just get a replacement cat pipe?

I did also take the wasgate housing off (4 10mm bolts at the top) because I thought it might be stuck open. There seemed to be a lot of play side to side in the actuater but really I don't know what excessive play would feel like as I have nothing to compare it to. The spring in there seemed ok too but I guess that is something else that is hard to tell just by looking?

Mark - 88 Turbo

[swinnen]

Hi Mark
Did you increased the boost before?
If had the similar problem whith a carbd turbo 1988
problem was incorrect fuel mixture and ignition
When you increas the boost or upgrading your turbo on a carb turbo go to a specialist for rejetting the carbs or it wil cost you a lot of money(engine kaboem)
Mayby this is the problem
Brgds Eric

[AZ88Turbo]

Hi Eric,

Thanks for the idea but my car is electronic injection with a TEC3 ECU so I'm pretty sure it is not that. Plus it happened in a period of about an hour when I was on the track and the ECU hadn't been changed in that hour at all. I'm going to check for exhaust leaks today and see if I can see anything.

Thanks again,

Mark

[lotusguy]

AZ88Turbo said:

Hi Eric, Thanks for the idea but my car is electronic injection with a TEC3 ECU so I'm pretty sure it is not that. Plus it happened in a period of about an hour when I was on the track and the ECU hadn't been changed in that hour at all. I'm going to check for exhaust leaks today and see if I can see anything. Thanks again, Mark

Mark,

After rading this post and how the problem came on over time, especially on the track, I am convinced that a. You developed a leak in the turbo mounting or vac hoses or b. You have a problem with restriction in your cat.

Check to see that these are ruled out, especially the flow from the cat. Happy Motoring!...Jim'85TE

[AZ88Turbo]

lotusguy said:

Mark, After rading this post and how the problem came on over time, especially on the track, I am convinced that a. You developed a leak in the turbo mounting or vac hoses or b. You have a problem with restriction in your cat. Check to see that these are ruled out, especially the flow from the cat. Happy Motoring!...Jim'85TE

Hi Jim,

I am tending to agree with you, as I can't see anything that looks or sounds like a leak, and with both you and the guy who rebuilt my turbo suggesting the CAT, I think that has to be my first choice. As I am not sure how to check the flow, all I can think of is to get it replaced, or actually removed. I'll have to stop by a local muffler shop and ask if they can chop the thing out and weld in a replacement pipe.

I'll let you know how it goes.

Thanks for all you help,

Mark - 88 Turbo

[AZ88Turbo]

Hi All,

Just wanted to thank everyone who helped with this. I "gutted" the cat this morning and WOW! what a difference! Turbo is back to a good spool-up and it is way better than before. Wish I would have done this ages ago.

Thanks again,

Mark - 88 Turbo