951 Consideration

Anaxagoras1986 · 07-19-2006, 06:07 AM

I've been seriously considering purchasing a 951 for a new toy. I love my little NA but I really like the idea of having some more juice under the hood and to get that from a NA would be pretty expensive and counter-productve.

I've looked at alot of the Lindsey Racing kits that seem pretty attractive- 340WHP kit, and the basic chips/boost controlers/etc. have a few questions that I hope someone here might be able to help me out with though-

-What type of power do most people run reliably with a stock long block? Turbo upgrades? Intercoolers?

-I hear alot of people talking about headgasket issues when the boost is really cranked up- how much is too much?

-When overhauling the engine, how is it bored out for new slugs? The M44 engine has alu-sil bores right? If you bore it out won't that eliminate the silicon etches in the bores?

-When overhauling, what do most people prefer for a piston, rod, and ring combo?

Thanks for any info and opinions guys!

Anaxagoras1986 · 07-21-2006, 05:48 AM

Suprised no one responded to this. This forum is usually pretty helpful with information on 944s.

Lawrence Coppari · 07-22-2006, 04:31 AM

About 10 years ago I upgraded my 951 engine with the following:

1. K27 turbo
2. MAF
3. 1.1 bar boost
4. Head gasket
5. Extrude honed intake and matching head
6. 3 bar fuel pressure
7. Enlarged boost tubes and throttle body

Engine had about 90K on it when this was done. Unknown previous owner. Rod bearings changed in 2001. Car has 162K on it now and has done 80 track events (probably more). Can't comment on how much power engine makes but it does not make 340 at the wheels. I suspect about 310 based on acceleration figures.

Never any problems with engine other than oil leaks.

Anaxagoras1986 · 07-22-2006, 07:25 AM

Thank-you very much Lawrence! This is exactly the type of info I've been wondering about. If I am to get another 944 I think I will do a similar build!

nize · nize's Garage

Quote:

Originally posted by Anaxagoras1986

-What type of power do most people run reliably with a stock long block? Turbo upgrades? Intercoolers?

are you wondering what power you can get from a turbo upgrade on the stock block? or an intercooler upgrade? or both? that would depend on the turbo, the intercooler, the tuning (chips, etc.), the wastegate, etc. etc. there are so many variables in your question i'm not surprised nobody responded. reliable power at the wheels with a stock block can range from 250whp to 400whp. there's even one guy in vegas who's making over 500whp in a daily driven reliable 951. it really comes down to how much money you're willing to spend.

Quote:

Originally posted by Anaxagoras1986

-I hear alot of people talking about headgasket issues when the boost is really cranked up- how much is too much?

another question with too many variables. injectors, wastegate, and tuning are a few of the things that can affect how much boost you can run reliably. numbers can range from 15psi to 25psi. most people who experience this problem usually just cranked up the boost without changing anything else, which is one of the most idiotic things you can do to any boosted car.

Quote:

Originally posted by Anaxagoras1986

-When overhauling the engine, how is it bored out for new slugs? The M44 engine has alu-sil bores right? If you bore it out won't that eliminate the silicon etches in the bores?

this question has been discussed, dissected, and answered many times, try searching.

you will find way more information than you'd need.

Quote:

Originally posted by Anaxagoras1986

-When overhauling, what do most people prefer for a piston, rod, and ring combo?

most people don't replace pistons and rings with an 'overhaul'. the only reasons i've heard are either because something broke, or because they're going to a bigger bore motor (2.8 liter mod). these are available as a package from places like lindseyracing, powerhaus, etc. which you can also do some searching for.

Lawrence Coppari · 07-23-2006, 11:23 AM

I forgot to mention that I installed a second oil cooler in series with the factory one plus a modified oil pan that has channels and a little one way door at the bottom of the sump. The oil pickup tube has also been lengthened so it is closer to the bottom of the pan.

The second oil cooler made a big difference for track days in hot weather.

Anaxagoras1986 · 07-24-2006, 05:40 AM

I was wondering what people usually get without touching the bottom-end but upgrading the turbo, intercooler, etc. I'd be happy with 350WRHP for a toy. The Lindsey kit seems pretty attractive for this...

And I am very aware of the issues associated with not tuning a FI engine. Assuming that the car is tuned properly, you can put as much as 25 pounds in it? That's pretty amazing!

Overhauling/Rebuilding- I looked into Powerhaus, Lindsey, etc about parts for the 951. I was just wondering what people are running here.

Thanks for all of the info on this!

Tedro · 07-28-2006, 05:58 AM

If you're stepping from an NA, you'll probably be tickled with a stone stock 951. If you enjoy 90th percentile driving, the minor mods (cat bypass, chips, MBC and a day at the dyno tune) will make the car even better. I considered big gains for mine, and I've been that route with motorcycles, cars, airplanes. In almost every instance of hot rodding I wished I'd stopped at a point sooner than I did. I blame flying an F16 for this syndrome. Its hard to get fired up over 100 more HP now.

Pricing pistons was enough to keep mine at a modest output level.

86 951

Anaxagoras1986 · 07-28-2006, 06:08 AM

The Falcon is my fav military plane.

I have been in cars that would blow the doors off of 99% of 951 out there so my step from a NA won't be that shocking... I just miss driving around in my 44 (it's parked right now) and I figured that now that I will have some extra cash I can step it up a bit and get a much better one.

AaronM · 07-28-2006, 08:19 AM

Quote:

Originally posted by Anaxagoras1986
Assuming that the car is tuned properly, you can put as much as 25 pounds in it? That's pretty amazing!

No. Above 15 PSI you really should replace the stock injectors. Honestly, I wouldn't trust the stock head gasket above 18 PSI from what I've heard.

The block itself should be OK to 25, but there's a lot on the top that you'll need to "massage" to make it reliable.

Anaxagoras1986 · 07-28-2006, 09:22 AM

Yes I would assume that the injectors might need to be upgraded for that kind of boost.... I was wondering what the shortblock was capable for boost without rod, piston, etc upgrades. 25 pounds ona stock shortblock is pretty good imo!

AaronM · 07-28-2006, 10:26 AM

Quote:

Originally posted by Anaxagoras1986
Yes I would assume that the injectors might need to be upgraded for that kind of boost.... I was wondering what the shortblock was capable for boost without rod, piston, etc upgrades. 25 pounds ona stock shortblock is pretty good imo!

Aside from the pesky #2 rod bearing, the bottom end of these engines is incredibly durable. Rods, pistons, and crank are all forged on Turbos from what I've been able to tell. Some say that the later turbos use cast pistons, but I've never been able to verify that. There seems to be a big disagreement over that question.

Anaxagoras1986 · 07-28-2006, 10:46 AM

Why would one of the rod bearing be a problem? Some sort of strange vibration?

AaronM · 07-28-2006, 12:28 PM

Quote:

Originally posted by Anaxagoras1986
Why would one of the rod bearing be a problem? Some sort of strange vibration?

Oil starvation in hard driving. If you're going to track the car, I strongly recommend a baffled oil pan.

Anaxagoras1986 · 07-28-2006, 12:44 PM

Interesting... I wonder if having the oil galleries drilled out there or putting orfices elsewhere would help?

nize · nize's Garage

just get the oil pan baffle mod from lindsey.

and fyi, i've run 21psi with stock injectors and stock gasket with no problems before.

i wouldn't do it again, but i didn't have any problems when i did.

you could also have the stock injectors flow-matched and pro-cleaned for higher flow and safer a/f.

AaronM · 07-28-2006, 03:32 PM

Quote:

Originally posted by nize
just get the oil pan baffle mod from lindsey.

and fyi, i've run 21psi with stock injectors and stock gasket with no problems before.

i wouldn't do it again, but i didn't have any problems when i did.

If there aren't problems, why wouldn't you do it again?

From what I've read, the ECU will start pushing the injectors to 100% duty cycle at WOT between 15 and 18 PSI. Personally, I'd want to have the injectors at no more than 85% duty cycle at WOT for a little margin of safety.

nize · nize's Garage

i wouldn't do it again because race gas is expensive. if i could get hold of some, i'd have no problems bumping it back up to 21psi without reservations.

i'm currently running at 17psi as a daily driver and the motor is still running overly rich, which means there's room for more boost. it's been dyno tuned, etc. so i know it's still well within safety margins.

i'm waiting to get the wolf3d ems before doing any major mods/upgrades.

Anaxagoras1986 · 07-28-2006, 04:22 PM

I think I'd be perfectly happy with 17psi for a DD. What were you putting down at 17psi?

nize · nize's Garage

270hp and 346tq at the wheels.

even with those relatively low numbers, i've yet to encounter a mustang or corvette i couldn't beat, even the latest 06 supercharged svt's.

i suppose i'd lose to one of the new 2006 600hp vettes though.