1993 turbo question - Bog at Upper RPM

[WarWagon]

The engine just revs over ~2200 RPM with a lack of power. Good power down low. I think it should be taking off like my Dmax does rather than just revving up. Stock exaust and factory no kitty (Not saying it should be a dmax but it should be showing power up there.)

I am curious as to how smooth the wastegate need to move and if there are any tests for it? I think mine may be too stiff or binding shut. 1993 is a factory spring unit...

 

[DieselCash]

The GM-3 / GM-4 Turbo that comes on the 1993 6.5TD is a horrible inefficient Turbo.

You should upgrade it to a GM-8 or ATT. :thumbsup:

A GM-8 sales for $200 - $500 and ATT sales for $700 - $800.

 

[bk95td]

If your wastegate was sticking shut you would be getting full boost not lay down and die after 2000 rpm. THere should be resistance in the control rod but no binding at any spot. The GM 3-8 turbos all use the same internal parts[turbines,bearings ect]. The biggest difference is the 8 has a better elbow to the down pipe. The 8 also has the wastegate in the elbow instead of the main housing.I've read several threads where custom elbows were made.
The att may be a great turbo. No long term durability records on a 6.5 yet. At least that's my excuse[besides lack of$] not to buy one.

 

[Diesel -T]

I believe the torque curve for the 6.5 peaks around 1800 rpm or so ,then falls off really steeply , thus the lack of gumption at higher rpm,s .
Would the att change the graph?

 

[Slim Shady]

If your wastegate was sticking shut you would be getting full boost not lay down and die after 2000 rpm. THere should be resistance in the control rod but no binding at any spot. The GM 3-8 turbos all use the same internal parts[turbines,bearings ect]. The biggest difference is the 8 has a better elbow to the down pipe. The 8 also has the wastegate in the elbow instead of the main housing.I've read several threads where custom elbows were made.
The att may be a great turbo. No long term durability records on a 6.5 yet. At least that's my excuse[besides lack of$] not to buy one.

How many miles is long term duranility in your mind? I have turbos with over 30,000 miles on them. enough to say they are durable? There are no gaurantees they will live for ever but they were made with long term durability in mind, I didn;t go cheap on the manufacturing.

 

[Slim Shady]

I believe the torque curve for the 6.5 peaks around 1800 rpm or so ,then falls off really steeply , thus the lack of gumption at higher rpm,s .
Would the att change the graph?

YES

 

[bk95td]

I wasn't trying to be insulting. 30,000 really isn't long term either.It does look very promising. I know you did alot of homework. As said ,I can't afford one yet, let alone 6 for the 6 trucks i own. lower iat and better mpg make it very attractive.
On the same note ,the bw/ihi turbo serve the average person well. Just not quite as effecient as the att.

 

[Diesel -T]

Nor was I (trying to be insulting that is). Just wondering was all.

 

[WarWagon]

Looks like the exhaust manifold gasket is leaking really bad on the passenger side.

What makes the GM-8 any better than the 3 with the same wheel sizes?

 

[DieselSlug]

Its all about the elbow. I noticed the EXACT same thing with my truck, when im in OD it feels like it has more power to pull up a slight incline. But yet it will shift down and go to 2500 or so rpm and just wing!! Feels useless up there.... There really sint anything you can do, i really want to upgrade to another turbo, but i have no money to do so after the expensive rebuild. Does anyone have any pics showing the two elbows (gm4 and 8) in comparison? I really want to also get a chip...

 

[Matt Bachand]

Are you sure your TCC is locking up? Reving without pulling sounds like TCC issue.