Jim Morton

Dal:

Thanks for your reply. It is appreciated. No need to buy, we'll do dutch treat !

I try quite often to assist folks without "ram-rodding" an opinion on them. Kurt might disagree...;^)

Ultimately Kurt will need to decide what he wants to do. He loves his 951, but is still getting used to the maintenance of the 951's turbo engine. Also, as Helstrm suggests evryone has different opinions and Kurt likes to review these various options and I respect that with our friendship.

From my expeprience of going down the route of building a 3.1 liter 951 engine, I looked into the various 8V heads back in 1997. Back then ceramic coatings were just becoming common to the hobbiest and seem to open up new options for exhaust porting. I was curious for Kurt to see if folks had started using the coatings as common place.

With regards to the bad ceramic linings, when reviewing core donor heads, I found cracking near the "hot spots" (edges, etc.) or caramic linings simply loose, but stuck in the port. This was on several 951 cores I could find locally. Unfortunately, this inpsections came after I paid to have the heads cleaned up, inspected and pressure tested, only to "throw it back". Granted these were core heads all having issues and having been put in the discard pile. I do not believe that we damaged these ports in our degreasing / decarb process but there were definate signs of damage. I was conerned that bits of ceramic could travel to the turbo turbine side...not good.

My suggestion to Kurt so far is to evaluate the availability of 951 cores vs. the additional costs of prepping a NA head. If in the end, parts prices have become more balances for the turbo valves, there may not be much difference to prepping a NA head to a "real" 951 head if it is simply seats and port coatings. For the moment, it would seems that 951 core heads are scarce locally, but fairly available if he buys remote. It will be interesting to see how this all goes.

Please feel free to PM me anytime, I still love 951"S !!!

FWIW, I have found some great turbochager info (Garrett vs. KKK) doing archive searches through your forum. Seems like dyno numbers we were getting back in 97 have become quite common place without having to go MoTec or 3 liter long blocks. Very cool...

Regards

Porsche-O-Phile

The other thing I've heard is if the ceramic starts to crack, those chunks are going through the turbine vanes. Not good. Probably VERY uncommon, but something that's been mentioned to me. . .

Helstrm

I have one on my shelf that came apart and shredded the turbo.

RolexNJ

Jim Morton:

I sent you a PM.

DanaT

Hey Jim,

Didn't you have a Black 951 that was named Animal? I seem to remember you were getting 300+ RWHP out of that car BEFORE most of these people even owned 951s. I think it was pretty fast at the open road racing wasn't it? It was radar clocked at around 172 IIRC.

But then, for some strange reason you sold the car. I wonder where it sits now???

BTW, that car scared me. One day someone took it out for a drive and came back. She told me she liked the car because she didn't have to slow down for corners. Soon thereafter she was telling me about drag racing (and really whooping) some teenage boys with a mustang. She doesn't get to drive the car much...

Also, I am getting ready to do the geometry correction kit cause the ball joints are worn. How much was animal lowered? A few inches? Just making sure before I buy the kit.

-Dana

DanaT

Also, Jim, Animal would have loved to have that 968 6-speed in her.....

Just thought you would want to know she still asks for it....
-Dana

NZ951

Jim,

PM sent buddy...

Jim Morton

Hey Dana:

Thanks for the recall. Yes, you are correct on all accounts. I think we got just over 300 RWHP on a DynoJet in the setup I sold the car to you with. That was on 102 unleaded "Trick" and a 3% rich fuel curve as I recall. The "official" Pony Express radar trap was 172 MPH avg. for 1 mile. 3 radar readings averaged. Best radar read for the weekend was 178 during testing...178 was hit just as the revsied rev limiter fired so I kept it just under the max RPM for the actual PE race. Keeping the oil from frothing was the biggest issue running the 951 at such sustained RPM's. Lot's of oil pan work and a oil/air separator in the cooler line. Anyone still do that???

Aninal is still a legend, at least in my mind... I should never have sold it !!! As you may recall a last gen. RX7 R1 caught my fancy...dumb move. If you ever decide to sell Animal, PLEASE let me know. Good karma might prevail.

For those curious, my 993TT is quicker and likely faster overall. However, the car is much trickier to drive and no where near as easy to "hot rod". For what's gone into my 993TT, I could have easily bought a 951 and modded it to a same amount of HP. Hmmm, why didn't I just do that....

Thanks guys !

NZ951

Jim, have a chat to TonyG, he is involved in 993TT and 996TT performance products since he moved on from 951 land...

buzzsaw

I knew I was inviting impassioned responses when I insinuated Porsche may have bungled a design...

Anyway, I'm thinking I'll stick with the ceramic ports, in Porsche we trust (now if I could just find a good core). When I get a little wilder with the short block, it appears an NA head gives me some more options.

BTW - I know why you didn't go with a 951, Jim. I've driven the 993TT. Even before the most recent beastly mods, it ran like a raped ape. Besides, you can own a 951 vicariously by keeping me from screwing mine up.

Matt H

AFAIK, Scott Gomes can port the exhaust side of the 951 head.
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Laust Pedersen

Conceptually ceramic lining in the exhaust port is good since it keeps the exhaust gasses hot, which gives more kinetic energy to the turbo turbine (faster and earlier spool) and to some extent (fully?) compensates for the long head to turbo path. This is very likely the same reasoning behind the header shields and dual shell X-over pipe.

Unfortunately ceramics are fragile and brittle, so the design implementation as well as worst scenario use becomes critical.
Typically ceramics have very low thermal expansion coefficients, so in spite of the higher temperature they should match (or be less than) the expansion of the aluminum. However it is probably a good idea not to create high EGT’s (push engine hard) before the block is thoroughly warm, since that situation would create the highest temperature difference, hence highest chance for stress crack.

In any case I am happy with Porsche’s solution, but also keep the EGT’s in check with water (ahem, when it flows).

Laust

DanaT

Buzzsaw,

You should have actually ridden in his 951....it doesn't do too shabby.

He built the car in the mid 90s before anyone else was pushing these cars like this. As a tribute to how well it does, it is going on 8 to 9 years that the car has been in a tuned state. Also, the open road racing isn't a few fast laps on a track an cooling down. It punishes the car.

I know that around 300rwhp doesn't seem like much, but how many of the people building the 951s are averaging 150mph, hitting the 170s, and so so for 85 miles through the desert in their 951s. I know there are lots of opinions, but I can tell you take Jim's word for it when he tells you what works.

Yes I have upgraded some parts of the car but the basics are still there. And it has been going well for almost a decade. How many other people can claim to have built a 951 that is fast and reliable?

Jim, did I ever send you the last picture with animal?

-Dana

badcoupe

there are thousands of other turbo cars even race cars that don't use sodium filled valves or ceramic coated ports. If it was that big of an issue then everyone would've done it. Porsche seems to be a minority on this issue. If nothing go buy some ferreas or something.

buzzsaw

Dana,

You're preaching to the choir.

Funny, you're praising the guy you bought a used car from. How often does that happen?

Jim's one of my closest friends. I didn't buy my 951 until he'd looked at it. I'm sure he appreciates your praise, regardless.

--Kurt