944 Turbo - Upgrades and Engine Capabilities

951 sleeper · 05-27-2005, 11:50 PM

I just bought an '86 944 Turbo (has done 178,000 kms / 110,000 miles) which is standard except for the following mods which were carried out just prior to purchase: garrett t3/t4 hybrid stage 3 turbo with 0.63 exh; Motec engine managment (M4 I think); Bosch 044 motorsport fuel pump; 74 lb injectors; HKS waste gate; K & N air filter with custom piping; custom 3.5" exhaust; custom piping for turbo and intercooler; custom exhaust dump pipe; xtreme clutch with 1350kg pressure plate; and short shifter. It has factory option Bilstein sports suspension package for '86 mod (not the M030).

The car is going to be a daily driver for infrequent track use.

Just have two questions:

1) How much power can I safely run through the engine seeing it has stock internals?

2) What are the best upgrades for suspension and brakes if I want to spend about $4000 AUD ($3000 US) all up?

pokey · 05-28-2005, 01:07 AM

----drool----
Want to trade?
I'll give you all of the stuff in my signiture, you just cover shipping...

951 sleeper · 05-28-2005, 07:52 PM

Sorry Pokey. I haven't even had a chance to even drive the car yet... it's still being tuned.

fast924S · fast924S's Garage

That should be one sick 951, You can run some big HP with stock internals, Im thinking like 325-350hp

ilikemy944 · 05-28-2005, 11:41 PM

uhh 325hp isn't 'big HP' ;P
I'm running around 300 with just chips and boost control...
On freshened engines, bearings, rings, whatever, I wouldn't worry about 400 or more at the wheels...
On orig. bearings I might be a little worried tho.

fast924S · fast924S's Garage

325hp isnt big for a 951 guy, but its big for all the NA guys :-)

951 sleeper · 05-29-2005, 01:43 AM

Dynoed it on Friday: 275hp at rear wheels (I guess approx 325 at flywheel) with 1.1 bar boost. But yeah, definitely the fact that the engine internals haven't been overhauled is a big concern for me. The car has been well looked after (i.e. full service history...) but it has done 110,000 miles).

Do you guys think that if I upped it to about 325hp at the wheels without reconditioning the engine I might run into some problems - e.g. a blown engine or head gasket? Would it drastically reduce the lifespan of the engine?

Any thoughts on brakes and suspension upgrades?

Lawrence Coppari · 05-29-2005, 03:14 AM

With all the mods you have, I'd have thought you'd be getting more power.

951 sleeper · 05-29-2005, 03:31 AM

Yeah, I would have thought so too.

Maybe I'm losing some power b/c I still have the factory BOV and fuel regulator? Otherwise, what else could be wrong?

Then again, maybe it's just because the turbo's only running 1.1 bar...

onewhippedpuppy · 05-29-2005, 04:38 AM

Did it hold boost all the way to redline, or start dropping off about 5k? If the factory DV is going, it'll bleed off boost at higher RPM. Old factory wastegates do the same, but you have that problem solved already.

You listed 74lb injectors, but you don't have an adjustable fuel pressure regulator? If you can tune it on a dyno with the motec, you can turn up the boost just so you can keep a good air/fuel ratio. Even at 1.1 bar, it's something that needs to be checked. I don't know much about motec, I assume it has a wideband O2 so that A/F can be monitored?

As far as reliablity goes, these are tough cars, but right now you're running 100Hp more than stock, the higher you get, the more strain you put on everything, from the bearings to the halfshafts, so it has to increase the probability of things breaking. Probably has a lot to do with how you drive too.

If you haven't driven it yet, get it tuned well for where it's at, then live with it for a month. My car should have around 240 at the wheels (determined from similarly equipped cars being dyno'd), and I feel that it is fast, but yours should be FAST!

ilikemy944 · 05-29-2005, 08:45 AM

Yeah, I bet 1.1 bar has a lot to do with that. Btw, I'm also probably around 310ish lb tq at the wheels. I'm running 18psi on the stock turbo, and everything has 180,000 miles on it :O
Btw, if you do your own work, bearings aren't that bad and they are good peace of mind when running it hard...

951 sleeper · 05-29-2005, 04:27 PM

I'll be able to see the dyno sheets tomorrow to check whether it's dropping off after 5K -but what is a DV?

Yeah, the car has 74lb injectors but still has the stock fuel pressure regulator. Should that really be changed over for something like a Bosch adjustable unit?

I'm pretty sure that my mechanic's got the A/F ratio sorted - I know the Motec M4 unit that's been installed has Bosch 4 wire wide band lambda sensors so I think that A/F is good? Does that mean I don't really have to bother with installing an adjustable FPR?

onewhippedpuppy · 05-30-2005, 03:57 PM

Sorry, DV is a lazy way to write diverter valve, it's a recirculating blow off valve essentially. If you run a true BOV on a 951 it screws with the air metering, causes rough running sometimes. If the A/F ratio is ok where it's at then you should be ok, but if you turn up the boost an adjustable FPR would be the way to go.

rage2 · 11:39 AM

The internals are strong. On stock internals I made 460whp at 28psi of boost on 103 octane fuel, ran like that forever, never could get 'er to blow up when I had my 2.8L ready to go in. Lots of track time, probably more track time than street time at one point. The most pump gas power I made (94 octane pump gas) was around 340whp. These are dynojet figures.

My 2.5L setup was similar to yours, except I used SDS instead of Motec. I had about 140,000 miles on the clock when I got the same stuff installed. To ensure you dont "blow" head gaskets, upgrade your head studs, otherwise you'll go through head gaskets like there's no tomorrow. My combination of headstuds, o-rings, and stock headgasket worked perfect. Held up perfectly fine.

As long as the tuning is right, and the octane is there, IMO the stock internals are very strong and near indestructable. Tuning is the key, and since you have Motec, you don't have to mess with other people's chips for other people's cars.

rage2 · 05-31-2005, 11:54 AM

OK read through the rest of the thread, here are some more thoughts on the tuning aspects.

The stock cycling valve is useless. Install a proper blow off valve that stay closed at high boost while the throttle is open. The stock one will leak with an upgraded turbo. You can read more of my issues on the stock cycling valve on rennlist:

http://forums.rennlist.com/rennforums/showthread.php?t=64063

Your fixed FPR is fine. You have Motec. Tune your fuel curve through Motec. Fiddling with the FPR is for people that don't upgrade their fuel management (stock ecu, chips etc) and want to tweak their fuel curves by adding more or less fuel everywhere. It's a ghetto hack.

FIND SOMEONE THAT KNOWS HOW TO TUNE. Not saying your shop doesn't know, but MAKE SURE they know. You have to be very careful with timing once you start pushing your fuel's envelope, especially working with pump gas looking for the last ounce of power. At peak TQ under boost, you don't want to run any less than 16 degrees of total timing for the street, 18 degrees of total timing for the track to keep EGT's in check. When tuning on race fuel, make sure you have a separate map, timing requirements are different for different fuels (especially if you play with leaded fuels). What else... air fuel ratios, the "sweet spot" I found was at 12.3:1 under boost. Don't run any richer to get higher boost, it'll make less power (richer mixture robs power, negates the effect of more air in the engine). Oh, and the final trick, after about 5600rpm when tq starts to drop off, start cranking up the timing to get closer the edge of detonation (don't have my timing map handy to give you exact numbers). When doing so, you reduce the high rpm TQ dropoff effect, and in turn it holds your peak HP a little longer. I made my peak hp at 6500rpm with stock cams using this trick.

Have fun

.

951 sleeper · 05-31-2005, 05:48 PM

Thanks rage. That info should be really helpful.

So what I gathered is that for the moment I should upgrade the head studs, replace the o-rings, get a proper BOV and make sure the tuning's right as recommended. What kind of BOV would you recommend?

I've read that our dyno figures in Aus are 15% lower (can anyone confirm this?) than US dynojet figures (because we use a different dyno to the dynojet) so with the conversion to US dynojet terms my car has approx 315rwhp (230kw) at just over 1 bar running on 98ron pump gas. Does that sound about right given the mods? Also, the head gasket was replaced at some point but do you think that the car would be OK for a while (i.e. 5000 miles or so) with the existing head gasket and studs running that sort of power or is it pretty urgent to get the studs upgraded?

rage2 · 05-31-2005, 08:02 PM

Upgrade headstuds, add an o-ring groove the block or the head, then clamp 'er down. BOV, anything will do. I bought a cheap $50us one, and it works great.

Yes different dynos show different power. The chart I posted was done on a Mustang Dyno (280whp@12psi). I ran it same day on a dynojet, posted 315whp@12psi. I always use the same dyno, so I can compare results properly. At 1.1bar it's a bit low (315whp). At 1.1 bar I was making around 340whp on a dynojet.

As for running stock studs, you'll see the headgasket go fairly soon if you run anything over 300whp. Been there done that.

Rmills944 · 08:35 AM

Try 400Hp with the Vitesse Racing Stage 3 kit. I believe it was dyno'd at 409WHP.

http://www.vitesseracing.com/

There's a couple of people running Vitesse kits on Rennlist's 951 board.

rage2 · 06-02-2005, 01:33 PM

Quote:

Originally posted by Rmills944
Try 400Hp with the Vitesse Racing Stage 3 kit. I believe it was dyno'd at 409WHP.

http://www.vitesseracing.com/

There's a couple of people running Vitesse kits on Rennlist's 951 board.

Yea, vitesse makes great products, but irrelevant in this discussion since 951 sleeper already has Motec. Just remember those figures most likely wasn't done with pump gas. On race gas, it's not hard making 400whp. With stock cams, the 2.5L motor wont be able to make more than around 360whp on pump gas SAFELY.

onewhippedpuppy · 06-03-2005, 03:18 AM

When you guys say BOV, you still mean the diverter valve, right? Unless I'm totally mistaken, doesn't a true blow off valve make a 951 run like crap, because the air is no longer being recirculated? I've read lots of good stuff about the EVO DV, Paragon has it for like $115.