Engine rebuild - performance options?
 

Ok, this is not another "I have a NA and I want 300 hp. Does the E-ram work?", thread.

I am going to be rebuilding my motor in my 87na auto-x car very soon. I am looking for opinions for what I should do "while I am in there". I know there is some performance to be had in there, so I want to get it.

It still needs to be drivable on pump gas and run cool with the AC on. Even though it is not a daily driver anymore, I want it to be able to handle it when the need arises.

I will definatly blueprint and balance the entire lower end.
Install balance shaft delete kits.
Match port the head, intake and headers.
Do some mild port cleaning on the head, cc the chambers, and do a good valve grind.
I already have headers and a good exhaust and a FR Wilk chip.

Suggestions? If you have a good suggestion, say, like lightening the crank, and you have had it done successfully, please include the shop that did it for you.

Balance shaft elimination is done when the whole crank is knife edged. This removes a significant amount of the counter weights keeping the vibrations down. If you don't knife edge the crank don't eliminate the balance shafts as the vibrations will tear the engine from the car. Usually it fractures the fuel lines first.

Matching the ports will not hurt. Don't expect too much here. Don't do to much here.

IF you want to gain performance get the european domed pistions. You may have to get a different chip for the DME as the timing will become a bit critical. An anti knock circuit would help.

Is there adequate bafling in the oil pan? Whould this be something to address "while you are there".

What changed in the 89 to make 2.7L ????

Do a big bore 2.8L kit, do a MAF upgrade. Also I would upgrade the cam and get a bigger throttle body, Like you said, light port and polish, 3 angle valve job. Lighten, balance and blue print the bottom end. Get lighter and stronger connecting rods. The euro dome top pistons would be sweet. Try to hone the intake manifold. The problem with these engines is the air flow. IF you can make it breath your gonna get more HP.

maybe this is a dumb suggestion. i'm looking at my chiltons manual, it has specifications for the porsche engines. the 944s has 188hp and a 10.9 compression. it is the same bore and stroke as all the other 944 engines so why not build a 944s engine. I'm going to guess that the head was milled and valves had to be changed. i've seen on here that a a chevy 4 inch piston will fit if bored out. if the diameter of the cyc. is increased and the head is milled, it would have to result in greater power. there are a wide range of pistons available for the chevy 350. depending to what extent you want to go, there is always power to be had.

I know that I could transplant in different engines and such (like the 968), but I really do not want to go down that route. I know it is also possible (although the feesability is in doubt) to put on a 16v head. Again, I would like to stick with the stock layout.

I guess this situation really needs to be presented to a shop who has built numerous 944 performance engines. I know there are a bunch of shops out there with turbo experience, but who has NA building experience. A shop that can tell me what works, and what is not worth the money. Any ideas.

After balancing- a cam, Euro pistons, and an aluminum flywheel will give you the biggest gains. This is generally true for any engine. After that you start getting into expensive changes that don't net very much but are more for track reliability- ie, knife-edging/Pauter rods/coatings/etc.

Don't forget that non-stock pistons will need to have that weird iron coating as the cylinder bores are aluminum on these backward motors.

Anyway, just talk to John Milledge. He's the expert on these motors.

-nick

John Milledge, how do I get ahold of him?

http://www.jmengines.com/

Enjoy!
-nick

You can't just put a 16 valve head on an 8 valve car. You need to swap out the entire electronics to get the anti-knock circuits and the intake to get the AFS. There are also issues with the wider timing belt.

"Backwards engines". I can pull the pistions on a 200,000 mile 944 and stick new rings on them with out honing or boring and have them seat like new.

Settle down. These are some of the only engines that have aluminum bores and iron skirted pistons. Backwards from practically every other design. Is that what you're arguing?

It's a good thing you don't have to hone or bore because it's a PITA with aluminum bores. This is why it's better to find a replacement block if the bores are out of spec rather than boring for oversized pistons. Good idea? You decide.

-nick

Nice stuff, but $650 for a cam that only gives you an extra 10-15 hp is pretty pricey.

Maybe, maybe not. Figure 10-15 hp on a NA car is quite substantial. It may actually be more with a little porting, the headers and exhaust, etc.

I was quoted almost $1000 for a MAF conversion that would only be good for 5 hp. I thought that was redicolous.

I just sent a nice email to JM, hope to hear from him soon. I will keep you all posted on what I decide.

Jay