What to look for in an LS1 944?

Might be picking one of these up.

What do I need to look for to insure that the swap was done properly?

Did Angry ever sell his?

Doc: clearance of exhaust to motor mounts and starter; verify what radiator is in the car; did they install the hydroboost power brake system (+1) or does it have manual brakes (-eleventy bazillion); did they build shrouding around the radiator so that all air coming through the front fascia is forced through the radiator core; that's about all i can think of right now.

Tommy: yep, my V8 944 is long gone. new owner was very happy to get a complete running driving car for under two grand.

wow, under 2k. how well do they work out? I mean how much heavier is a v8 versus the stock motor, does the car turn better or worse?

I'm thinking something with a chevy/ford v8 swap at some point, maybe a volvo 240, or jag, but depending on how the 944 was, maybe I'll put that on the short list as well.

Andrew

with a very mild 355 and a slipping clutch, it went 13.96 @ 98 mph, with me feathering the throttle through 3rd and 4th.

NA diff won't take a ton of hard launches on drag tires, but i never had a problem with mine. the turbo diffs are supposed to be pretty robust.

iron block / iron head SBC adds about 200# to the front axle, but the handling can easily be remedied with readily-available springs bars and dampers. alan mccrispin drove it for me, so maybe he'll have something to say about it.

Is the hydro-boost necessary? I remember reading somewhere there is a smaller vacuum booster from another euro car that's a direct bolt on that will give you the clearance you need. I can't remember what the booster comes off of, or where I even read that, so maybe I'm thinking of something totally different.

Since I'm currently looking at my MG and saying "hmm, how can I fit a booster in that", I'd also like to hear more about the Hydroboost. It's not something I think I'll need, but it has me intrigued.

I've been told it's similar to a power steering pump or is actually part of the steering pump. I think Chevy/GM trucks use it.

It is powered by the ps pump, and they were available on a lot of the HD Chevy trucks and Astro vans of the '90s.

Here's a better pic.

thats a sexy looking brake booster... now i know what to get the wife for valentines day...

Andrew

But how well do they work? What are they like to drive? Would you want one instead of a vacuum booster, assuming you have room for both?

Love the pretty product shot with a rotor as a base, that's cute.

At least 8 cylinders. Minimum.

There are a few strategies for the brakes, one is to recycle the bmw hydroboost, a direct bolt on, the other is to use some sort of GM hydroboost, they are essentially the same thing but the bmw unit has more components, lots of power steering hoses... not sure about the chevy unit I pretty much scrapped the idea and went to a balance bar setup.

Each has the same fundamental components and operation: A pressure cylinder that stores power steering pressure, a pressure regulator, and a fancy hydraulic ram, the pressure cylinder stores about 10 pedal presses just in case your motor dies, both run off of the power steering pump. In the BMW unit the hydraulic ram is separate from the cylinder and pressure regulator, this makes it a bit narrower than the chevy unit, but not by a whole lot.

One thing for the 944s running bmw hydroboost, good operation requires that the pressure spring on the power steering pump is tensioned for higher presser (via a few shims or something similar) also that pressure cylinder fails on units causing weird spongy operation.

The thing is if you dont have the boosted brakes you can make up for it by drilling the brake pedal connection just a bit lower, I think its about an inch but id have to consult my external internet brain, the pedal also travels a bit more in that setup (944hybrids.com)

the BMW or the Mustang hydroboost will be better suited for use with the piston sizes in the 944 brakes.

corey, i don't see how any vacuum booster will package on a V8 944 unless it's mounted remotely and actuated by some crazy linkage.

redrilling the pedal sucks because it increases the pedal travel and it requires a lot more pedal force. some of that pedal force is lost to firewall deflection, which makes the pedal travel really long. so yeah, it'll stop the car, but it'll feel like crap doing so. perhaps the firewall can be braced, but i had neither the time nor the interest to pursue that option.

as to keith's question re. pedal feel with a hydroboost, go drive an SN95 cobra. they use the HB.

also ask the guy if it was a renegade hybrids kit (we are not fans of those guys) the kits have notorious inconsistency. Be sure to check the remote oil filter, there is a pinch point between the mount and the motor or somewhere along that line that has claimed a few hoses (and a few near oil-pukings).

If the headers are renegade hybrids brand then theyve ground the ID plate off of the original modified set of pipes, this causes a weakness that may lead the headers to crack, its a big problem and the replacement is just phenomenally expensive.

In reply to AngryCorvair:

Yeah good points, I am probably going to toss a brace in there soon, my whole braking setup is overhauled with lexus and turbo calipers... so its easy to forget what I still have to to

people SAY that the travel isnt so bad, and that the force isnt too much more than normal, since youve got more leverage... but I guess i'll be seeing for myself.

Tetzuoe wrote: In reply to AngryCorvair: people SAY that the travel isnt so bad, and that the force isnt too much more than normal, since youve got more leverage... but I guess i'll be seeing for myself.

people say all sorts of things, sometimes without experience or data to back it up. i'm not one of those people, at least not on this subject.

if the stock pedal was 5:1 ratio and the stock booster was 3:1 ratio, that's a 15:1 gain through your entire apply system.

remove the stock booster, and your system gain is now 5:1. pedal force required to generate a fixed deceleration goes up by 3x compared to the stock system, [EDIT] and travel increases somewhat due to firewall deflection under the greater pedal force.[/EDIT]

redrill the pedal to give (using an easy number for this example) a 10:1 ratio, and your system gain is now 10:1. pedal force required to generate the same decel as above is cut in half compared to stock pedal with no booster, but is still 1.5x greater than the stock system. and now your pedal travel for that same decel is 2x longer than stock.

consider also that the firewall is not designed to react that much force, and distorts quite a bit -- i measured iirc about 1/2" firewall deflection on my car, and had drilled my pedal to give 8:1 ratio compared to the stock 5:1. so that 1/2" of firewall deflection is felt as 4" of pedal travel. that is definitely not insignificant, and is definitely outside what i would say "isn't so bad."

i did not stay at a holiday inn express last night, but i am a brake systems engineer.

Unfortunately, driving Cobras isn't an option around here. If you told me to track down a particular F150 or F250, no problem :) I think I can fit a vacuum booster in my application, but I was curious about the Hydro-boost in case it came to that. I had no idea they were so prevalent. I should check underhood, I might have driven one to work today...

In reply to Keith:

drive a diesel. no throttle = no vacuum = no vacuum booster unless there's also an electric vacuum "pump". most diesel pickups have hydroboosts, AFAIK.

full-size GM vans have been using hydroboosts since at least 2008, for packaging reasons.

LOL well, keep in mind im just quoting stuff from ages ago.. hence the giant asterisk.. Im not sure how accurate any of it really is anymore, I need to pop back into the hybrids site.

Sadly this has reminded me about the dust collecting on my 944 project. When I get back into it ill be bouncing some stuff off of your corvair, gotta know if ive ruined my car completely yet

Thanks Angry. Turns out I've driven a hydroboost system then, my father-in-law's monstrous Ram 3500 with a Cummins. The thing has an amazingly firm pedal. I'll look into them further.

Generally speaking and looking at it from a performance driving aspect, assuming both options are available, would a vacuum booster be preferred? They certainly seem to be more common unless packaging or a lack of a throttle require otherwise. Or is it one of those cases of "it doesn't matter what the underlying tech is, it's the implementation that matters"?

Sorry about the thread jack, but Corey started it!

In reply to Keith:

they feel different, that's all. because the HB uses fluid under pressure being supplied by an engine-driven pump, you get feedback from the system through the pedal. since a vacuum booster uses air, or the lack thereof, the pedal feedback isn't there.

What isn't good about the renegade kit? I've talked with the owner, he used the renegade kit, but kept the stock manifolds, not their headers.

he also didn't use a hydro boost for the brakes, it's unboosted right now. How hard and expensive is that retro fit?

docwyte wrote: What isn't good about the renegade kit? I've talked with the owner, he used the renegade kit, but kept the stock manifolds, not their headers. he also didn't use a hydro boost for the brakes, it's unboosted right now. How hard and expensive is that retro fit?

not hard, if you can tap into the power steering lines to do it. does the car have a power steering pump on it? probably not too expensive either, i'd guess with junkyard parts and custom hoses you're looking at $300 in hardware.