Thom

The LR Super 75 uses a T70 compressor wheel.
With a #8 hotside and 20psi of boost it won't be too bad to drive but under full load backpressure will be immense and EGT will explode, and that is with a 2.5 engine already.
Thinking of a #8 hotside on a 3.0 would be asking for further trouble, unless coupling it with a compressor so tiny that it would question the point of building a 3.0.

lee101315

I had a LR 75/8... The turbine wheel was at least 10 mm bigger than the k26/8 it was replacing...

blade7

Is a T70 wheel 67mm ?, I'd agree a #8 hotside with that coldside doesn't add up on a 3.0 though I've read the replica hotsides are bigger than the original KKK's. It's obvious the 75 is biased towards top end but people that are using them seem to be saying there's enough boost from 4k to make them viable.

lee101315

https://rennlist.com/forums/944-turb...side-pics.html

In the first post, there is a side by side comparison of the lindsey racing "8"hotside next to a K26/8

Thom

The (bad) things we noticed on the car of my friend were with a Turbonetics #8 KKK replica housing, so we can reasonably suppose it may be even worse with a smaller original KKK #8 housing.

blade7

The turbo I have has a #10 replica housing, hopefully adequate for a 3.0 ?

Thom

Adequate I don't know, but for sure won't be quite as bad as an #8.

MooreBoost

if you have the turbo already why not just bolt it on? it unbolts if its not goimg to work..

blade7

I'll wait until I have a MAF kit and larger injectors.

nick_968

Your old turbo used a number 8 hotside machined to take the t04e stage three turbine wheel Thom which we have both used on our 3.0 engines. It is fair to say I ran into a brick wall on the dyno at anything over .9 bar boost at over 5k rpm but it still made 400hp. When the weather warms up enough to make the swap I will be trying it out with the spare replica number 10 hotside I have to see if that improves things without too much noticeable loss in spool and allows it to hold 1 bar+ to 6k rpm. The jury is still out as to whether this is what caused the HG to blow at the dyno but excess backpressure is probably a good theory. Given that experience I would agree with those who say stick to the number 10 housing as that is what most if not all of the aftermarket vendors suggest for a 3.0.

Thom

Well yes Nick... I must say I wasn't thinking of your experience when I made that comment, just thinking about what Sly has been seeing.
I suppose your better JME cam made the back pressure issue more evident on your engine than it did on mine with the NA cam? Hard to say...

My other friend with the 444bhp engine uses an #8 KKK hotside but with a modern Borg Warner turbine wheel and sees no more than 2.0 bar of back pressure, so maybe the stock housing can still be kept if used with such a turbine wheel.

nick_968

Well I guess if I fit the number 10 housing and nothing changes except slower spool then at least we will know the housing is not the blockage. I also agree that the JME cam should in theory exaggerate any back pressure issues.....

Thom

We were almost going to measure backpressure with Sly on Sunday but got lazy and just drove off onto the Autobahn, but even from the passenger side the back pressure felt pretty obvious when going full load at high speed. It felt nowhere near as bad on my (even larger) engine with your turbo and I never had HG issues in the same condition, at least issues that were not already present.

Would be interesting to see pics of the "tongue area" between the two housings when you can make some, I never had a close look at those KKK replica housings.

gruhsy

I'm running the super 75 on my 3.0 .68a/r p-trim T4. I don't see any back pressure in my gauge tied into the test port on the cross over pipe. I'm sure u have seen pics of my exhaust I've posted. I see full boost by 3800. Not stock cam either.

Edit : Hot side is a V-band not 4 bolt different than #8 or #10

running_cold924

what about a stage 5 turbine?

I have a stage 5 in mine with a #8 housing. I am running a GT35R wheel (56 trim) in a T04E compressor housing measuring .60 a/r. I love my spool in mine.

but this is still a 2.5 in mine, not the 3.0 like he is toying with.
I just think the stage 3 will be too small for the 3.0.