DOC Race going big with Precision PTE6870 turbocharger to replace Comp 6465BB on their N54 shop car

[DOCRace]

Well this is as big as we can go with the current manifold design and location. Took the tapped out Comp 6465BB and installed the PTE6870 which is their newest bad boy turbo packed in a small frame turbo. I got the 1.15A/R which I planned on using with a built motor. Since that might not all be together for a while I was just itching to install it so I did yesterday.

Note to anyone wanting to run this exact turbo (1.15A/R) with our manifold: It fits but you might have to trim the engine cover, bend the heat shield, remove some of the factory chassis glue. The housing is huge compared to the standard **66 1.00A/R. I made it all fit without cutting the engine cover and also installed the new DOC Race lava turbo blanket.

First off I just want to say there have been a lot of horror stories about Comp turbos. I may have just gotten a lucky one but this turbo has been super reliable. The only thing that did annoy me was there was oil coming out of the compressor housing and made it look bad when I showed people the car. Other than that it made 750whp on race gas. I put a good 10K miles, some race but mostly pump and never had an issue with it other than the oil in the compressor.

First impressions after install: At first start up it was a lot louder so I can definitely tell the exhaust is now really moving. Took it out for a spin to burn off all the oil left from handling the exhaust parts and yes, it has quite a bit more lag which is what I was expecting. Got it back to the shop, checked everything again. Also noticed that once I turned the engine off the turbo spun for much longer than the Comp. I would say it spun for almost a good minute.

Took it out for another spin. This time took it up higher in rpm and boost logging everything this time. Again, this thing sounds like a different car. Much louder and again more lag. Was able to log a couple runs. A/F was spot on still so I feel safe enough to at least drive around town low boost. 4th gear I was about to reach 20psi at 3850rpm. I wouldn't say that's too bad. With the Comp 6465 I was able to get 20psi by 3300rpm.

So forget about all this low boost talk, what does this really mean? I talked to Andy at AD-Engineering and he's going to try to squeeze me in for a tune also adding a couple other things that I will mention later AD-Engineering and Horsepower Barn have a few cars going to Shift Sector 1/2mi race in Oregon in Spet. 10-11 which I will be attending as well so we will be seeing some fast BMW's out there. I will keep everyone updated on the tune.