No mod to engine support beam?

New poster here with a question for you smart guys. I've got a 1991 944S2 with a very sick engine. Been looking at the LSX engine swap for a while, but now with renewed urgency.

I'm an autocrosser. A proposed rule change in the SSM class would allow any engine swaps, but there's a catch. You cannot change any suspension attach point locations, and you can't modify, more than minimal drilling of holes or slight reshaping for clearance (1 lb max material removal), the basic structure of the car. Given that, you can put any motor in any car, if the rule change goes thru, which I think is probable. I'd be limited to 5.3 liter for weight-per-displacement rule reasons.

So, here's my 1st question: Is it possible to install an LM4-based motor in my car without lowering the engine cross-beam support? I think most LSX swaps shim down this piece? The issue is that the ends of this beam contain front suspension attach locations, which cannot be moved from stock.

2nd question: To be competitive nationally, this 5.3 motor needs to produce 400 lb-ft at the wheels over as wide an rpm range as possible. At least a 3000 rpm range, but 4000 would be better. Do you guys think this possible?

Thanks in advance.

It can be done, but it will be extra work. You'll probably have to start by shifting everything (motor, trans, torque tube) as far back as possible. Angling the TB downwards like Admin and a few others have done would help too.

Beyond that, you're just going to have to get the motor in there and then see what you need to do. It CAN be done, though.

Instead of shimming the cross member I modified mine so the center was removable, then build my own center section out of 2x2 steel. This allowed me to put my engine lower, and i didnt have to modify my oil pan for clearance, but I did move my steering rack down about 1/2", so that requires some bump steer correction. but I dont know if your rules classify that as suspension, I wouldn't think so but what do i know. I have pictures if you would like, it wasnt hard and I could point out a few things you could do to improve it.

Mark

The only real reason we all space the crossmember is so we dont have to modify the hood. Its crazy what we all (and I) go through for just that reason.

If youre just racing it and the rules are strict, install a slight buldge in the hood.

If you want to install the LS style motor in your car. Contact me I have everything you'll need or I can do it for you. It'll save you a ton of money in the long run.
But, if you are going to do it yourself. Do a hood bulge, or install one of my fiberglass hoods that have the bulge made into it, or lower your cross member and just re drill the A arm mounting points up the same distance that you move the cross member down. No real problem there.
Power? If you want to call and discuss with me exactly what you need or have to have, and you'll follow my advice, we can make it work out to be in the area of power that you need.

Thanks
Admin

Wow! Thanks for the answers everybody gave, the day after Christmas, no less. I've read thru a bunch of posts in the mean-time... lot of really good people on this site and some fantastic fabricators. XSCHOP blew me away, for instance. And Admin seems to have a nice business going with some cool products.

To recap/comment on a few points you guys gave:
1) A pinned fiberglass hood is a necessity for getting weight off the front end. I can do a bulge, as long as it's within 1" of the original body line. My min weight will be 2660 lbs at 5.3 liters and that's about exactly what I estimate, within the rules, without spending megabucks.
2) Engine back as far is possible is really good as well for weight distribution, which is going to be critical for handling. I have to keep the glass hatch, but fiberglass front fenders, hood, front facia, and sunroof replacement panel are legal. I can ditch the bridge spoiler and lower-rear diffusers (I think) but have to add a big wing out back and front splitter for aero.
3) Steering rack is not suspension, so it can be moved.
4) The full buildup for national competition would be strictly a race car, even though the class is called Super Street Modified. Monobal suspension joints, no rubber anywhere, something like 600 to 800 lb/in springs. No fun at all on the street.

I'm still in the planning stages and, like I said, the rules haven't been changed yet. But, I'm thinking get the 5.3 in there running anyway for an awesome street car then worry about building it out to big power and full suspension later if the rule change happens.

One other question: would a dry-sump setup help the clearance? It's not a necessity for auto-x, but if it make things easier... I don't have great fabrication skills. More of a tear it down and put it back together guy.

In the meantime, I got a bunch of 3.0 liter engine pieces to sell off, but you guys are def not buyers!

If your not a fabrication I would strongly recommend purchasing parts that are known to work together from myself or xschop. I personally wouldn't spend the time or space doing a dry sump system. The smallest oil pan, even for a dry sump system, will still need some sort of motor lowering(=cross member lowering) You can move the motor back an 1/2" or so, if you do that you'll continue to add to the mods needed. I would suggest doing your motor modifications before you install it, It'll take a lot of labor to go back in and do it later.
Trust me, I know what it takes, I do this for a living.....................
ERic

I have a set of Z06 heads that I would love to install now, but dual mc's and bracket tell me otherwise. I hate just having to think about contorting myself again to re-do the pedal-pushrod ajustment after removing the mounting from the firewall. Take Eric's advice to do it right the first time while the engine is out. The clutch set-up is the most important and that pilot bearing to TT shaft interface is #1 worry and second is the TO bearing to clutch spline interface/adjustment. The rest is trivial and has been done many ways here on the forum. Luck has it that the 944 X-members can be welded,drilled,slotted,ground down and beer basted LOL. Get yourself a set of TPC uprights/plates and low-profile LS oil-pan, C5 BH and C5 adapter plate and a V8 swap trans mount , then slot the X-member engine mount holes rearward by 1/2" to 5/8" then grind your TB top alloy as much as possible. Install the engine and grind some metal from the hood brace. You may be surprised that you don't need X-member spacers to bring it down for hood clearance.

How much does the stock hood weigh anyways? Mine seems pretty light, not sure how much weight a fiberglass hood would end up saving you...

Doc, I installed a carbon fiber hood on Gene's car for him when I had it. There was a large amount of weight difference. Maybe 20lbs or so. Although the hood was pretty flimsy it worked and looks good on his car.

Hood weight: I don't know whether to believe it, but GT-racing catalogue says the stock hood weighs 79 lbs. I dunno. I went out to the garage and played with mine. It's got both a dynamat layer and the standard sound deadening layer on the underside. It's pretty heavy, but I don't think it's 79. I could believe 59.

Thanks again for more replies. I definitely intend to buy parts known to work absolutely where ever possible. I think the suggestion to get the engine built before installing it the first time is a good one.

And a correction: I reread the SSM rules. The hood is totally free. So I can make one from cardboard if I want. Whatever bulge might be necessary is no problem as there is no 1" limit like I thought. (That is only for roof-mounted panels: replacement T-tops, targa tops, sunroofs, etc.)

Also, if the higher engine position causes a problem with torque-tube to underbody clearance, I can reshape using BFH technique.

I had mine off when I repainted the car and it doesn't feel like 79 lbs. I think I've heard 50lbs before and I'd believe that. IIRC the fiberglass hood from gtracing is 25lbs so there is a significant weight savings. I don't recall where I got this spreadsheet from but this has some good information in it.

944 Weight Savings

Stock 944 hood without shocks or latch.
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GTracing fiberglass hood without shocks or latch.
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Big difference between 39 lbs and the 79lbs GT racing claims the stock hood weighs!

A 22 lb difference is still a bunch, not sure if it's enough to make me spend the money though.

In a recent tv show, they showed that the LSx intake can be turned around (throttle body in the front or back). Would there be clearance for the throttle body if it faced the rear of the motor?

If you get rid of the fan on the other side of the firewall. I remember seeing a picture where somone did this with a racecar and put the intake where the fan was.

When I first ran my 944S2 with LS1 at our local track it ruined one bearing and the crank after oil starvation in the tighter corners. My engine had the modified Moroso pan cut down for clearance at the cross member and the cross member spaced as well. I had my shop install a three quart accusump where the charcoal canister used to be behind the driver side fender liner and it has held up just fine at several track events and autocross events. Good luck, Bob Blackwell.

I keep an extra quart or so over the dipstick line in the Moroso pan, better safe than sorry. Also add ZDDP if you are running full synthetic, heck add it to regular oil as the EPA wants you to blow your engine with regular dino.