300whp 951 on a budget

[stitch2k1]

So a few months ago I picked up a nice 951 motor from a guy. Spring tensioner, forged rods, came with a K26/6 (in usable shape) and a #8 hotside among other things. I would love to trade it for a S2 motor, but I don't think that's happening and I could use the turbo experience so I wanna get it into a running shape, with 300whp (thereabouts) on a budget. Looking for some feedback/help with planning this one out.

It needs the head pulled to clear crap out of the cylinders since it was stored with no plugs in it. I've already taken the pan off to confirm it being forged rods as well, and it was still completely filled with (non sludged) oil. I borescoped it and it has minimal scratching on the cylinders, what I expect from an old 944 motor so I'm just going to leave it.

• Bottom end: Forged rods already, I'm going to swap the bearings with ACL ones, and I have a set of new stock main bearings if for some reason you guys think I should change them out.
• Headgasket: Replacing it with a widefire. I know it's not the best, but I don't want to go overkill. I do happen to have some Raceware headstuds, so I could change those out at the least.
• Injectors: I have a set of stock turbo injectors that are currently at an injector shop so I'll have those. I have heard some saying I need bigger injectors and some saying I don't. There was a guy wanting to trade some 72lb Siemens injectors but I would need a custom chip to run that AFAIK. I think I can cross this bridge when I get there.
• Turbo: the K26/6 I would like to send to Evergreen and get rebuilt with that #8 hotside, but I want to do that down the line.
• Exhaust: I got the later style (with the flex joints) headers and a stock downpipe. No crossover, but I'll be grabbing one of those. Past that, I would like to make something eventually, but I'll just run a stock exhaust. A friend of mine made a clone of a Fabspeed exhaust and I keep saying we should make one for this.
• Wastegate: I see the Tial EWGs getting used a lot, I think I have a stock wastegate I need to check my parts out again.
• Intercooler: I just have a stock one for now, as far as charge piping I would like to make some of my own, I might be able to do some welding not sure.
• Intake: I have a weird modified stock intake manifold, which I got in that parts lot, but for now I'll leave the stock. For the air intake I don't have anything right now, but I think I will just run it stock with a big cone filter just to get it running, and worry about making a nicer air intake later. AFM no MAF here.
• DME/KLR: I have 3 to choose from, one of them has a chipped DME with a Autothority chip. Seems like their stock boost pressure chip too.

I think that covers what I got pretty well. My thoughts on 300whp came down to Widefire, Evergreen rebuilt turbo, possibly bigger injectors, a nice exhaust, intake, and wastegate with a good chip tune. I never got my hands on a complete 951, I've worked on a couple but never modified so this is all new to me. My experience is all anecdotal from friends.

[Tom]

300 is doable on stock injectors and airbox/injectors, but doesn't leave much room for error. One thing to consider is if you move to bigger injectors, you'll need some way to map them. If you just use bigger injectors with APE or other 951 performance chips, it will just run rich across the board. My suggestion would be to not worry about the dyno number too much and just get the most you can out of the mostly stock parts.

APE chips came with a banjo bolt with a restrictor inside, which helped create a boost spike. Most also relied on a 3BAR fuel pressure regulator, so you'd need that too. I'd ditch the banjo bolt thing and just get a $50 manual boost controller black knob.

The Tials are nice wastegates, I have one. The issue with the stock wastegates is that they get sloppy over the years -- springs weaken and valves burn. When I went from my old stock WG to the new Tial, it was a night and day difference without changing anything else... On the budget theme, consider shimming the stock wastegate, if that's what you use (and make sure the valve is good) -- the shims will help remove some of its weakness.

K26/6 will need to be reworked in some way to get where you want to be. Widefire, raceware, stock intercooler, stock intake/exhaust (no cat), should all be fine. You can make a very nice street car, with plenty of power, with a k26/8 turbo, good chips, no cat, good wastegate, and manual boost controller.

[AudiSport]

I'd probably skip the widefire HG and get the composite one from 928 motorsports.

[stitch2k1]

300 is doable on stock injectors and airbox/injectors, but doesn't leave much room for error. One thing to consider is if you move to bigger injectors, you'll need some way to map them. If you just use bigger injectors with APE or other 951 performance chips, it will just run rich across the board. My suggestion would be to not worry about the dyno number too much and just get the most you can out of the mostly stock parts.

Yeah the injector mapping is what dissuaded me from those 72lb injectors. I do plan to ditch the stock airbox, and make something better. 300whp is just merely a goal, I'm trying to do that without breaking the bank.

APE chips came with a banjo bolt with a restrictor inside, which helped create a boost spike. Most also relied on a 3BAR fuel pressure regulator, so you'd need that too. I'd ditch the banjo bolt thing and just get a $50 manual boost controller black knob.

This is the one w/o one I think, since there's no KLR chip but I'm not 100% sure. Here's a pic of the chip. I also have stock DME chips I can use from the get-go.

The Tials are nice wastegates, I have one. The issue with the stock wastegates is that they get sloppy over the years -- springs weaken and valves burn. When I went from my old stock WG to the new Tial, it was a night and day difference without changing anything else... On the budget theme, consider shimming the stock wastegate, if that's what you use (and make sure the valve is good) -- the shims will help remove some of its weakness.

What's a good way to inspect it? I haven't even looked at it, not even 100% sure I have one TBH.

K26/6 will need to be reworked in some way to get where you want to be. Widefire, raceware, stock intercooler, stock intake/exhaust (no cat), should all be fine. You can make a very nice street car, with plenty of power, with a k26/8 turbo, good chips, no cat, good wastegate, and manual boost controller.

Yes reworking the K26/6 with Evergreen and my #8 hotside is planned, but that'll come later. That's definitely the most expensive thing to do, so that'll be the cherry on top. Once the project is driving then it's a lot easier to stomach that purchase. Changing those headstuds are going to be fun. I already tried removing them from a kaput block I have and they didn't wanna budge with the double nut trick haha.

I'd probably skip the widefire HG and get the composite one from 928 motorsports.

2x the money, I don't disagree with it being better but it's more than I need.

[Fast951]

300rwhp is doable without much effort or cost. Assuming you have a solid running engine (or rebuilt) to start with:
- upgrade your K26/6 to a k27/6
- add a performance chip and a 3bar FPR
- a way to raise boost to 15-16 psi (a simple $20-30 ball and spring MBC)

If rebuilding the engine, I would use a Wide fire head gasket.

Using the #8 hot housing with the K26/6 will cost you more than you think. If you decide to use the #8, start looking at a different (not K26/6) turbo.

Your project success depends on the health of the engine and a proper tune.

Since you have an S2 3L engine, why not add a turbo and run low boost?

[danmartinic]

I'm using a ball & spring MBC upstream of a "black knob" MBC... the two in combination seem to work very well!

The ball & spring gives initial quick boost build

The black knob is a safety preventing any ball & spring spikes and overboost (I understand that B&S can spike dangerously)

Why are the cone aftermarket filters so popular? Seems to me the stock intake draws colder air from outside the engine compartment (provided the rubber surround is in tact at the intake end)

[chester]

If you just use bigger injectors with APE or other 951 performance chips, it will just run rich across the board. My suggestion would be to not worry about the dyno number too much and just get the most you can out of the mostly stock parts.

This is so true. I had a Max951 chip and it ran rich- but did produce prodigious power

[stitch2k1]

300rwhp is doable without much effort or cost. Assuming you have a solid running engine (or rebuilt) to start with:
- upgrade your K26/6 to a k27/6
- add a performance chip and a 3bar FPR
- a way to raise boost to 15-16 psi (a simple $20-30 ball and spring MBC)

If rebuilding the engine, I would use a Wide fire head gasket.

Correct me if I'm wrong, you need a different fuel rail to get a 3bar FPR?

Using the #8 hot housing with the K26/6 will cost you more than you think. If you decide to use the #8, start looking at a different (not K26/6) turbo.

K27/8?

Your project success depends on the health of the engine and a proper tune.

Yeah we'll see how that one goes. I think this block is fine. I might try to leak down check it in the next week or so.

Since you have an S2 3L engine, why not add a turbo and run low boost?

Building a second car, for track purposes. Not going to molest my S2 aside from MAYBE adding ITBs in the future. It's a daily driver, and WAY too nice to use to chase lap times with. I want a car I can 'afford' to lose and don't rely upon as an everyday driver.

I'm using a ball & spring MBC upstream of a "black knob" MBC... the two in combination seem to work very well!

The ball & spring gives initial quick boost build

The black knob is a safety preventing any ball & spring spikes and overboost (I understand that B&S can spike dangerously)

Which MBC do you use? LR?

Why are the cone aftermarket filters so popular? Seems to me the stock intake draws colder air from outside the engine compartment (provided the rubber surround is in tact at the intake end)

I'm going to be going with a cone type ducted down towards the stock pick up point. Cheaper than a stock air box, and takes up less room, easier to work with. I don't care about originality in a track car.

[Tom]

You can use the Bosch 3 Bar FPR with the stock fuel rail. Looks just like the factory one. That's what I use.

Fast951 sells turbos -- or at least he used to -- he's Vitesse Racing. His Stage 2 turbo would be perfect for your goals, but I'm not sure if he still sells them.

Are you keeping the AFM and just adding a cold air snorkel to replace the black plastic from the factory?

[danmartinic]

Are you ... adding a cold air snorkel to replace the black plastic from the factory?

Has anyone confirmed a benefit of an aftermarket snorkel vs factory air intake? I just don't get the "cold" part; these cones draw from inside the engine compartment while the factory plumbs from outside the fender ...?