info on upgrading stock turbo

[fl89tta]

need to change an oil seal in my stock turbo. Figure while I''m in there I'll upgrade if possible. Anyone have any info? If I have to machine anything and how extreme I can go. Where to get a rebuild/upgrade kit? Any tip, pointers, tricks, any help will be appreciated. Thanks.

89fltta

[JP112_89]

Two sites I followed when I did mine. I also did the elbow. The elbow is where most of your gains are. Looks stock too! Joe



Porting a stock turbo & inlet bell comparison


Port Your Stock Turbo

[UNGN]

Originally Posted by JP112_89

Two sites I followed when I did mine. I also did the elbow. The elbow is where most of your gains are. Looks stock too! Joe



Porting a stock turbo & inlet bell comparison


Port Your Stock Turbo

Yikes. Don't port a stock turbo to an aftermarket bell. This is truly confused.

The bottleneck of the stock turbo is at the face of the impeller. You want a smooth, parabolic venturi going into this face diameter. Making some kind of non ideal, double bumped goof nut approach to this face won't make it flow more and could very easily make it flow less.

Matching it to a stock bell is a hell of a lot less work to achieve a smooth parabolic shape and there will be ZERO difference you would ever see on the most accurate of dynos going to a bigger bell.

Port the turbo to aftermarket bell if you are running a TA49 or bigger. Don't do it to a stock turbo. You'll end up with a mess.

[JP112_89]

Sorry for the post. I DID NOT not use the aftermarket bell. I Bellmouthed the Inlet and the Outlet of the Turbo and smoothed out the turbine housing. I also enlarges the WG hole with a end mill to help prevent boost creep. Followed the instructions and enlarged the hole about 25 %. I have done the IC neck and elbow too. I had a perfect seal when I reassembled the turbo and installed as well as everything else. NO LEAKS or mistakes.

Made a difference at higher boost. I run 22lbs. of boost on my stock turbo with 3/1 Race gas to 93 octane. Everything worked out very well. Took longer than I expected but I took my time.

I had these links saved to my computer. I should have read the first link before I posted. It was the first turbo I ever reworked so... Joe

[UNGN]

The Waste gate hole is another area that has irked me for a while.

By properly bellmouthing the inside of the wastegate hole, you can keep the same diameter and it will flow as much, if not more than a wastegate hole that has been milled larger (and has square corners inside).

A square cornered hole only flows 62% of a hole of the same diameter that has has a proper bellmouthed approach.

The problem with making the hole diameter larger is it's real easy to go too big and junk your turbine housing.

[JP112_89]

Thanks for the info. I used a 15/16 end mill to enlarge the hole. I called Red a while back and he told me to be careful and do not over do it. My boost creep is gone. Also, not to change the topic but my TTA whistles more when I boost after smoothing the elbow. I noticed a performance gain for sure.

Thanks for more solid info UNGN. You really know your stuff . I would not like someone to overdo it and wreck their stock original turbo. I was sooooo careful when I did mine. He is better off probably sending it to Precision and getting it rebuild.