Plan on doing a N/A build; need some pointers

[SlowMoe]

Howdy y'all, just bought an '85 944 with 155 on the ODO. Currently it runs well, with the exception of a pretty bad grind when going into 2nd at the upper rpm's

My plans are to pull the motor and trans, rebuild them for performance and re-install. I am shooting for 225 whp

So far my plans are
-New bearings, gaskets and seals
-New 12.5:1 pistons
-Necessary crankshaft maintenance
-Headwork
-New cam
Some kind of engine management
-Repair/ replace 2nd gear synchro or whatever is causing the grind

My questions are
-What can I get away with as far as head work goes? Do I need to get new valves, plus valve job, or can I reuse the old valves and just do the valve job?
-What do I need to do to the crank in order to maaintain reliability?
-What kind of engine management will I need with a fairly aggressive cam capable of 225whp?
-Will I need anything else to reach my goal? I believe the car has an aftermarket exhause, it has a test pipe for sure..

[Gawernator]

That's a lot of HP out of the 2.5L NA motor but is possible with a ton of money.... you'll want 951 valves at the least

[alan6272]

Wish I had your money LOL I have the heart but getting old too. Where you from by the way? And welcome to the forum.

[FrenchToast]

Welcome to the forum!

You'll probably need basically everything. Intake, exhaust, cams, crank, head, valves, everything. And MoTeC (or some other standalone tune-able management system) or carbs.

Keep in mind the '88 models have higher compression and '89 models have a 2.7L block.

And stickers. You need lots of stickers to get above 200.

Be prepared to spend about 10k to reach 225 hp with the 8V block. To get 225WHP, even more. It's a lot to get these engines up to that kind of power.

Take care,

[p-talk]

I would recommend starting with a 16v motor instead, that'll get you *much* closer to your goal.

[9FF]

I may be wrong but I don't see how you can fit 12.5cr pistons with the stock cam let alone one with a higher lift.
10.9cr is stock flat top and even those are fly-cut for the valves.

[Gawernator]

I wonder what your goal is for this? If you're rich then by all means go ahead but it would be a lot easier and more cost effective to go buy a 3.0L motor and then upgrade that for a real monster

[mhariush]

I have an 87 S 16 Valve engine if you go that route...

[ckelly78z]

Lots of expensive head porting/polishing and port matching along with a free flow coated header, and most likely an aftermarket intake manifold fitted with larger injectors. ($$$). Don't forget the lightweight flywheel and performance clutch to handle the extra power/torque. You're going to need the right grind cam with special pistons and H-beam rods, a knife edged crank, upgraded hi-flow oiling system with extra capacity, an easily tunable stand alone EMS, and many other misc items.

This get's stupid expensive really quick with no real shot at achieving the 250-260 flywheel HP necessary to see 225RWHP. (gaining 100 HP over stock can be done, but not recommended).

[mikepellegrini]

Welcome to the forum.

I hate to be a wet blanket but I don't think there's any real way you can reach your goal with a NA engine. I've seen guys spend absolutely crazy amounts of bucks and as far as I've seen, no one has reached that kinda HP.

Your best bet is to buy a 951. They're a lot easier to mod. Much better bang for your buck.

[alan6272]

How about spending the money restoring and making a show stopper

[mikepellegrini]

Originally Posted by alan6272

how about spending the money restoring and making a show stopper

+1!

[Gawernator]

Mike doesn't the 3.0 NA make more than that stock

[uvachief]

Lindsey racing.

[rhett]

If you are thinking of getting your anticipated HP gains then there is no need to repair the transaxle you currently have - it will simply self-destruct if you try to push those kinds of power through it. You are going to need a much higher spec unit ($$$) such as the 951 unit with oil cooler and LSD at the very least, or perhaps the 968 unit? I don't have the experience in this area to advise too deeply, but I know of some guys who fitted a standard transaxle to a track 951...it didn't last too long!

If this is for track use I am sure lots of forum members can offer advice as to what is possible (and probable costs too). If for road - it does seem a bit ambitious for a 25+ year old NA car.

[v2rocket_aka944]

Get a 3.0 16v engine and put a 2.5 crank in it (may need to get new pistons for this). That'll put you at 2.7L, big bore small stroke. Put a dry sump oil system on it, some Michael Mount hot camshafts/springs/etc and spin it to 8000RPM. Use the S2 or 968 intake or make a custom one. You *could* use the stock Motronic but might as well go for something hotter.

I say 16v because the stock 16v heads will flow more air than all but the most-expensively-worked 8v heads. The 8v heads are pretty good, but they can't compare when you are looking for a lot more naturally aspirated flow.

[kcoyle]

C'mon, where is the "LS swap" suggestion?

Oh wait, I just posted it. Soemone had to do it.

[guru944]

Slowmoe:

Nothing other than a 16 valve head will get you the airflow for that power NA. A 2.5 - 3.0 Shortblock with 11:1 will work nicely. Cams could be stock or Webcams for more top end. SS undercut Valves and good head porting will do wonders. Remember fuel and ignition upgrades will also be needed. MAF conversion is the ultimate cherry on top...
PM me if needed. Keep us posted on your progress. Later

[H.F.944]

Originally Posted by guru944

Slowmoe:

... Cams could be stock or Webcams for more top end. ...

I wonder why the cams on a 944 NA could be stock? The timings of these camshafts are more diesel-engine like than anything else. My 944/I from 1984 has a stock cam with
IO 1° ATDC
IC 49° ABDC
EO 43° BBDC
EC 03° BTDC
Intake Duration: 228.00 degrees
Exhaust Duration: 220.00 degrees

So there is no Overlap -->indeed -4.00 degrees!! For the time of 4 degrees exhaust and inlet are closed before the inlet valve opens. How will the cylinder completely get rid of the exhaust gases, when the exhaust closes 3° before TDC. Then the inlet opens 1° after TDC. This means to me. How on earth will there work any scavenging?
Afaik, any normal petrol-engine has a valve timing, where there is a valve overlap of at least 10° degree where scavenging can take place.
So it's hard for me to imagine, if you have a stock 944 camshaft there is no need to or rather no room for improvements; camshaftwise.

[mikepellegrini]

Ha!

I have no doubt you can get one of these 2.5 engines to clock 8,000 RPM. But if you do it very frequently, the thing will likely explode.

Gaw, you're right: the 3.0 L engine is listed at 208 HP right out of the box. I'm guessing that's at the crank. Not sure what that'd be at the wheels.

And yes, a standard NA transaxle will also self-destruct if coupled with a 220+ RWHP engine. They're just not made for that kinda torque.

Neither is the suspension in an NA car made to handle the increase in power.

So like I said at the beginning, if you want 220+ RWHP, your best bet is to buy a 951.

220 RWHP in a 951 is easy. 951Max Chips, a 3" straight exhaust, a 3 bar FPR, a MBC, a new dual-port wastegate and a wideband O2 sensor. Cost is under $2,000 (I added it up - $1,605 at current prices).

With that set-up, my son's 951 was dynoed at 250 RWHP and 300 RWT.

Or you could go nuts like my son did - he wasn't satisfied with the 250 RWHP, so he upgraded to 75# injectors, a Lindsey Super 65 Turbo, and a Lindsey Stage 2 MAF with piggyback and an Innovate LC-1 Wideband O2 sensor with a digital AFM gauge. To better handle that power, he also installed Koni adjustable struts with adjustable ride height with 425# springs and solid strut mounts, Koni adjustable shocks with 550 # Rear Coil-overs (torsion bar delete) and a KEP Stage 2 clutch and pressure plate.

He hasn't dynoed it yet but it's scary fast.