I need a Turbo Guru in help with matching a turbine wheel

[mattpopp]

Ok guys, I read on here a fare bit but rarely post anything. So a quick run sown of my truck. 07 6.7, 150stix, Stg 3.5 5.9 Floor It pump, Compturbo 68/81/.96 (also have a .81 housing), and the rest is not to important. But the turbine wheel has no trim it is a straight cut wheel. That I think is killing me.

I did 600hp and 990ftlbs on Relentess dyno yesterday. Smoke never cleared up and I know there is more in this truck but the turbo is just very laggy and I am sure that is holding me back.

So I have been battling with this low end lag on my turbo. I am on my third different Compressor wheel in attempt to get rid of the lag, along with the forced replacement of one gernaded wheel. The wheel came aprat because I over spun it and the casted wheel just did not like that to much. So it is a billet compressor wheel now. I am almost sure that this lag is coming from the Straight cut turbine wheel. It just seems like the exhaust is not staying in contact with the wheel long enough to drive the turbo. DP pressure is just way to low. The only time the drive pressure is above boost when I hit about 45psi then the DP is a few psi above. The turbo is almost like it is built for a gasser. The guys at Compturbo are very awesome guys to work with but the diesel market is something they are slowly getting into. Joe the owner has been working hard to get this right for me and a few other guys out here. But I think he is applying his gas engine knowledge it a diesel which is almost the opposite of what we need.

So I am going to send my turbo back to get the turbine wheel replaced with a wheel that has some type of trim to it. A turbine wheel with a trim or the more trim it has will keep the exhaust in contact longer. The trick is to find a trim and A/R housing that match that can keep the exhaust in ther long enough to drive the turbo. But to tight of housing or/and to much trim and there will be to much DP and it could easly over spin it on the top end.

My goal is at 50psi boost to have between 60 to 70 psi of DP. At 20psi boost I want to see over 30 psi of DP. Pretty sure that I will be putting a Waste Gate on to control relief pressure after letting off of the throttle. Unless somebody buys my TRX 450r then I will just call Source and get twins but I dont see that happening anytime soon.

So what I need from yall that are running after market turbos. What are the specs of it. Primarly what is the Major and Minor diameters of the turbine wheel. If you have a 74mm turbine wheel that is the Minor size or Exducer size, however you call it. But I want to know the Inducer/Major size. So what size housing are you running. How well does your turbo light and give me the characteristics of the EGT's. What is WOT, what is crusing, and what is accel like?

Just any input on the matter will help

but if this truck was only a drag or sled truck I would not change it as it pulls hard on the top. Just not setup up good as a daily driver now.

 

[Backhoe man]

i run a s400 based 68/74/.9 it is a little slow to spool 1800 or so, inducer is 83 exducer is 74. I also ran a garret 4094 DBB that was a 68 exducer 77 inducer it spooled lighting fast and could manage egts in about all applications except on the dyno but so far all the turbos I have tried run very hot on the dyno think it is just a 6.7 thing. I also ran a 64/71/.80 71 exducer 80 inducer it did not spool as well as the garret but much better than the s400. In a 6.7 I think a .9 to .95 A/R is about right and it is gonna need a waste gate for the top end. Make sure you look at the exducer on the compressor side as well it adds to the weight of the mass and effects the spool. What size is the body of your turbo it looks as if their turbos use a garret CHRA are you based on a gt40 or a gt42? The 83/74 boosts at 1 to 1 until about 35 psi and then it starts to get a little overwhelmed garret make a wheel very similar to this that should fit you turbo, I am told it is slightly more efficient than the BW wheel I run and you have the advantage of the DBB setup. Good luck the turbo thing can be a pita on one of these motors

 

[mattpopp]

I am not familiar with garret turbos, meaning I have never used one personally. So I am not sure how close the Compturbo is compared to the garret. I do know that my turbo does not use a thrust washer and it is a triple ceramic BB turbo. I also thought the .90 or even the .96 housing would be great but with the straight cut wheel it is not that great at all. Even with the .81 housing on there it is much difference in spool up.

So my goal is to figure out what Size and Trim of a turbine wheel do I need along with what size housing do I want.

but since I put the billet compressor wheel on the turbo is horribly loud. It has this unforgiving whine to it.

 

[Smokem]

I'm assuming it is a CT43 series, did they actually think a 100/R-trim wheel would work on the street? I would go away from the T frame, jump up to the BW stuff in their CT5 series.

 

[Backhoe man]

Sounds like a very inefficient turbine for the application that you have it on, what are they offering you as far as wheels go? The Garret compressor in the 67.8 inducer did the same thing it never shut up got very irritating. If you are going to gate it I would look at a efficient turbine on the bottom end and let the gate do it job on the top. 80/71 or 82/73 would be my guess or in that general range.

 

[mattpopp]

Ok, so if I do a 71/80 turbine wheel life should brighten up for me. Looks like I will be ordering a 38mm gate to handle everything else on top.

What size housing do y'all recommend for that size wheel? I may try to get them to set me up with a couple housings. A .96 and a .81 or .84


What have y'all heard about the cams in the 6.7. Seem that their cam could be less effiecient then a 5.9 cam due to emissions but I don't know

 

[GOT-Torque]

Sounds like your experience with Compturbo is about the same as one of the local guys.

A very expensive game of throwing darts...

I think he went thru 3 or 4 turbo's and still hasn't found one that works great.

 

[mattpopp]

Well I fixed the problem. It was pretty easy, just spend a arse ton of cash and get twins. I ordered a 64/S480 kit from Rip this morning. Should be a fix for me.