Cool thanks I will check the Video out. Thanks for the info most appreciated...

 

Later (1988) 944 10.2 c.r. piston rings are the same as 951. When I went to replace the rings with new replacements I noticed they were different, so went to the manufacturers website and compared p/n. Also, the regular OEM style 944 clutch that I'm using has stood up well under 250-300 hp (turbo now) but I think one reason is the lag helps preserve the clutch, I plan on replacing with 951 clutch & bellhousing one day but no rush.

 

As another brother mentioned, the stock pistons will probably limit you. I upgraded to forged oem 8:1 951 rods & pistons and considered this an opportunity to replace the con rod bearings. It was a lot more work but used 951 stuff is so cheap, why not?
However, you are right... it's laggy. Boost does come on until 4000 rpm. Putting on a smaller turbo or better yet a VGT turbo would help the boost at lower rpm.

 

Its a slippery slope.

 

Ring Failure not Piston or Rod failure

Ring Failure 2
http://roguetuning.com/944na_internals_-_the_limit
As part of our testing, we turbocharged a stock 1987 NA short-block. This engine lived on a steady diet of E85 to ensure absolutely no knock. We wanted to see the actual power limit of the NA internals, not destruction caused by knock. Our engine lived for ~9 months, being nearly daily driven at 17-18psi of boost, approximately 350rwhp! But it eventually could not take 2.5 times the factory power, and here is the result: RING FAILURE not piston or rod failure.
So that proves to me the NA bottom end is strong enough if I control Knock with Tuning Hi-Octane gas or E-85 which is available where I live. why does everyone think the bottom end is crap just because Porsche change it in the turbo they were limited by tunning and electronics in the '80s not so now. As I said before I plan on limiting boost to 12 psi
Thanks for the info on the clutch means I don't have to go buy a spec clutch right away

 

Why???

 

My NA is a '87 block, plan on using stock 87na rings just open the end gap to the max of what a turbo should be

 

https://rennlist.com/forums/924-931-...roper-way.html

 

Voith's project is the poster child for "project creep". He certainly knows of what he speaks. Respect.

 

Dwizle,
Thank you for posting the photos. It's been a long time since I read about the Rogue stuff and didn't know he turbo'd an 87.
I *think* your 87 has the better rings. When I disassembled an 87 16v 2.5, it had the beefier 951 grade/same as my (88 na) rings. I am assuming 85.5+ came with turbo grade rings.

Note: when I had my engine apart & went to install the new rings and noticed how flimsy the cheap Goetze rings were, I instead opted to re-use my original rings (with 120000 miles but good compression). Measuring the ring gap in the cylinders I think was around 0.030" so if anything is considered OVERSPEC which can lead to excessive blowby: crankcase pressure. Which I had to solve. If you research piston gap threads, you will find many people mention even new Goetze rings in a used engine will have gap that is over spec. https://rennlist.com/forums/944-turb...ton-rings.html
I'm saying this because you might be wasting your time "opening up the gap".

It's very interesting that the cast items were not damaged. You seem to have a good argument. I look forward to seeing your progress and wish you success!

 

It's Knock that kills the bottom end I personally broke the bottom end of the NA with engine knock snapped the #2 con rod. I read somewhere that the rings are the same just that with the increased pressure and temp the rings can grow n if the ends touch there goes your motor.
Ebay just said they delivered my pressure plate so the project will begin soon first thing first pull the motor swap Flywheel and get the engine running on the MegaSquirt if that's successful then either on to the turbo swap or S2 flywheel for the turbo and it's own MS system will post pics.

 

Did you ever get that car finished??

 

+1 Vote for turbo'ing an NA. In fact, I highly recommend adding boost, it totally wakes the car up!

We have been running a low boost setup on our Champcar for over a year now with no engine issues whatsoever. We did lose an NA transmission in hour 13 of a 14 hr race a Sebring a few weeks ago though... cause of failure is unknown.

https://rennlist.com/forums/924-931-...ons-944-a.html

 

No. But I've stacked quite a few $ bills in it so it'll run some day. And I want it to be spectacular when done.

At one point 10+y ago I had running donor turboS and perfect NA waiting for transplant. Then "while I'm in there" happened..

 

I hear you on that, Plans change but I plan on keeping it simple and cheap if that is even possible with these cars lol.
The concept is very creative and aggressive n I like that...