Dougs951S

I've been MIA for a little bit folks, driving my NA around and discovering more and more issues with it. At this point its more than I want to deal with, so here come the questions...

I want to drop the running complete N/A engine (with 951 bellhousing/clutch/ect and 951 intake manifold) into my megasquirted 951 chassis and boost it. It will be fed pure E85 so detonation will be a non issue and boost will be kept low to respect the cast rods. I only want to make 250 rwhp from the cast internals 9.5:1 CR motor. People make plenty of power on supercharged but otherwise stock S2 and 968 engines that use the same cast rods, so my question isnt about feasibility or longevity or tuning. My question is mainly about oiling. My 951 is an 86, and my NA is also an 86. The N/A oil pan appears to have already been tapped for the turbo oil drain from the factory, it has what looks like a 32mm plug in it. I have everything from my 951 as the car is still 90% together, so if I drop the motor in and tap the upper balance shaft housing for an oil feed, everything should work (I'm running a dry turbo setup as well which makes things a bit easier, and I believe the 86+ motors already have the boss ready to be drilled on the housing)

My issue is what to do with the oil cooler. Are the oil cooler housings machined/matched to the block? If so, I would not be able to reuse the 951 oil filter console, and subsequently would be relying on the N/A basic oil/water heat exchanger. I will be running a 951 radiator. Since both engines are 86 blocks, they both use the same 3 piece OPRV as well. Thing is, my 951 engine suffered a severe failure and who knows what kind of metal shavings are in the oil cooler and filter console, so if it would be ok in a purely street driven car, I'd rather just use the N/A heat exchanger/oil filter housing and not worry about changing it and having to reseal it. Do you guys think that will be ok in a car that's going to be driven gently? Anything else that will need to be changed that I am overlooking? Should be a simple swap in my eyes.

Thanks rennlist

JET951

The old NA rods are too weak & way too old( to rely on ) + the condition of the old conrod bearings are a unknown to just drop in as is ( way too risky )

If I was going to install a NA engine I would dismantle first & install good quality new con rods & bearings , there is only 4 of them so its not expensive & then replace all the old gaskets & seals & install the 951 head etc & install all the oil console etc on the engine stand & then install

As for the weak NA pistons , I would not go down that route , every time we have seen someone turbo "ing" or supercharging a NA 944 / 944S2 ( with its higher NA compression ) every one of them have ground their weak pistons into the cylinders even with weak boost levels & yes it may of been the wrong oils used in those engines ( low oil film strength ) but we have never seen a success full one yet ( success meaning in finished form and running with NO wear issues for at least two full years driving every day )

Running E85 , its fantastic except for one big annoying issue ( apart from high fuel consumption ) & thats starting the engine cold in cool to cold weather , it will eventually drive you nuts on an everyday basis

Rogue_Ant

http://www.roguetuning.com/944na_internals_-_the_limit

Dougs951S

Josh, the lil Mule was actually my inspiration for this, knowing that car's history I know that the cast internals will live on E85. its just a matter of knowing what I need to change/do to make everything bolt up and work. Have I about covered everything in my previous post? I'm planning on running 1 bar on a k27 turbo, at most it'll make maybe 300 rwhp and should survive long enough for my hybrid stroker engine to be done.


Install 951 intake/throttle body
reuse 951 motor uprights/turbo drain/mount
install 951 bellhousing
install engine
reuse 951 clutch parts
bolt 951 oil drain to my already-factory-tapped oil pan
remove plug in upper balance shaft, install turbo oil feed line

What is yall's opinion on reusing the 951 oil filter housing/external cooler after a major engine failure (it may have metal shavings in it, and I'm not sure if you can just bolt any oil filter housing of the same year to any block, or if they match the block in the same way the balance shaft covers do)? vs just running with the stock block mounted NA oil/water heat exchanger?

Rogue_Ant

The '87 block we used had the oil port on the balance-shaft housing - no tap necessary.

Re: oil-cooler. I took the 951 oil-cooler and lines to a local radiator shop, and had them clean it. (I told them it probably had metal shavings in it)

If that isn't an option for your, then for limited-life street car I would just use the 944 setup.


I would suggest keeping the boost to 12psi max. You will find that the higher CR means less boost for needed for moderate acceleration.

Raceboy

With 9.5 CR it will easily work and 300+ hp will not be a problem on any NA part you have provided you will tune it properly.

And yes, we have local 944 NA who swapped in US spec pistons and all 951 manifolds, K26/27 turbo, chipped DME+KLR and has driven this thing for almost 6 years, 320 hp.

V2Rocket

if it's just a stop-gap measure to hold you over until your stroker is built then go for it and let us know how it holds up. itd be good to have another data point to reference for future "turbo my NA" posts

i have considered doing this on mine but probably wouldnt go past factory 951 boost levels (~11lbs). with the higher compression it will be making a little bit more power than a regular 951, and with your management (aka no AFM) it would be even more than that.

gruhsy

Michael Mounts bearing mod for the rods is a great price if your putting in different rods.

As far as NA rods this is what I've seen

https://rennlist.com/forums/944-turb...s-old-car.html

Rod snapped before the bearings had a chance to fail. The NA just don't look very good quality wise when placed next to a set of RARST rods from my 2.5L

pormgb

Ran my NA boosted at 10 psi, I used a J&S safeguard for knock control with a GReddy EO1 boost controller.

The car was very fast but suffered terribly for blowby, at the time I thought it was due to boosting an old motor with old rings. When I converted the car to an LS6, I sold the motor and the buyer told me one of the rings were cracked.

N/A bottom ends are fine if they are new but as others have said, pistons rods and rings will eventually fail under boost.

odonnell

Doug, there's that '83 in Belton with forged rods....

odurandina

how bout just switching cars with Sausagehacker.

raleighBahn

The 89 951s have cast (NA) rods, unlike the previous turbo years. You should be fine there.

E-man930

Not the two 89 952 motors I have had apart...

Voith

My 89 951 came with cast rods and 2001 parts catalog has cast rods listed for turbo.

Dougs951S

Did you run an NA headgasket on that 10 psi motor? As far as the internals, as others have noted some 951S had factory cast rods and so do many boosted S2's, with a good E85 tune and 10-12 psi of boost, it should last a long time. The NA ring pack is the same as the turbo cars I think, so no trouble there under boost I wouldnt think if the NA motor has good compression and doesnt burn oil (so long as it isnt detonating).