dmoffitt

i see completely what DangerIsland and other people are saying about race car vs steet car, and i even liken all-season tires to mumzer's points about a "compromise car" - you can't have something that does well everywhere...

honestly, i could have picked up an older 951 with maybe 100k on the clock (not caring about the motor) and a straight, clean body, for about 6-8k and done the swap into that. but then i'd still want to do a suspension, brakes, weight reduction (quite expensive for the stuff from GT / racer's group) and while i don't mind paying what chris wanted for this chassis, i really can't justify spending more than twice that and then some to do it all again myself. is the car overkill for my needs? yes. would i rather have that overkill than always be wanting to add this, that and the other? probably.

it's kinda like having growing-room when you're a kid and buying shoes. yeah, so you have to grow into them, and by the time you have, they aren't brand new... but you've had them to use / enjoy and even if it takes a little polish to brighten them up, well, you get the picture.

by the time i will be using this car for a track-only car, it'll be in need of a full tear-down / rebuild anyway (or rather, i would want to do so as it is).

worst case, however, I can always take the more-vulnerable parts (struts, control-arms etc) and replace them w/ stock ones and set them asside for when it really is track-only... i'm not going to trash these parts nor anything else on this car, and i realize people want to see that this car is going to be well taken care of -- i hope it's obviously that's my goal too <img border="0" title="" alt="[Wink]" src="wink.gif" />

I consider it a piece of 951 / race history, i've been reading up lately on chris's accomplishments (both with this car and in his #411 996) and while i doubt i'll EVER live up to that, i've been a decently-good autox driver (won a Niagara region event with my rsx, kind of a shock to some) and am trying to get more into racing, with some DE events, instruction, etc... you have to start somewhere. my car is/was alreay outclassed, any time you play with boost on a 951 it's in SM2 with modded Viper ACRs etc, so that's no change for me... i'm not in it to win, i'm not building this car to try and beat the socks out of everyone by outspending them. i just know how i want it to be, and i want to compete with myself, improve my own driving skills. i could havce / would have done that with my stock 951, had i been given the chance, but following my "when it breaks, upgrade / improve it" approach has taken me WELL away from that, so here i am.

Steve Lavigne

If this car is as prepared as it's rumored to be, I would expect a bunch of tubing tied into a single point right about where a passenger would sit. Do you care about being able to carry a passenger?

M758

The car can carry passengers. I have seen it done safely on the race track.

Danno

The one thing that no one has mentioned is the area of benefits. I prefer to work in the shadows between the black & white simplistic ends. I don't have the numbers, but I would say that the delrin bushings you have already give you 80% of the gains of going to spherical bearings. Getting that last 20% isn't going to make as big of a difference as that first upgrade from stock rubber to the delrin. However, you will experience the negative aspects of removing that last 20% of compliance in your suspension.

Personally, I think the gains are minimal. If your paycheck depends upon that last 0.02sec in laptimes, then go for it. Otherwise, I think the enjoyment factor is more worth it.

CarreraCup03

Dave,

I think what people are saying .... is that Chris's car was not at all designed for the street. There are loads and road vibrations, not to mention an occasional pot hole, that will destroy the car if left as is.

I have a race/track only 944 turbo .. with complete solid bushingings from racers edge, solid engine and tranny mounts, spherical bearing camber plates, full custom valved Bilstien coilovers (1500lbs and 1000 lbs springs), 8 pt welded cage, etc.. you get the point.

I can feel every single bump in the road while driving to and from the pits at 10 mph. I would not want to hit a pot hole going 75 on the highway.

To drive Chris's car on the road you will have to add alot of rubber (bushings) ... and then it might make a fun street/track car. It is doable .. but will take some careful thought.

Good luck.

944turbo

dmoffitt

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by M758:
<strong>The car can carry passengers. I have seen it done safely on the race track.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">yeah, it's got room for 2 seats... all i want.

after talking to chris via email last night i'm likely going to use my factory motor / tranny mounts. he seems to think, however, that it's not worth it to replace any solid stuff with w/ delrin or even stock rubber - but i'm going to see if I can identify any critical areas that stand to take the most abuse from bumps / rough roads... as danno and 944turbo said, that extra bit you get from the spherical / solid stuff is very important on the track, but that's not this car's ONLY purpose right now, thanks for the suggestions guys.

chris is also putting on 800lb springs as obviously 2xxxLB is waaaaaaay too much, not only for a street car, but, honestly, i'm still learning, perhaps a little more weight transfer, etc would be a good learning tool, rather than having a car which's limits are SO high that you have to get dangerous before starting to feel things.

so - which bushings would everyone consider a "must" to change, which would be a "definately don't worry"?

User 41221

For a street car with heavy springs, I would go with Delrin all the way around, as I think you will stress rubber ones way too much under load and you would constantly be replacing them. Quite frankly, I bet you have a pretty high incidence of failure/wear with delrin too, but it will help distribute the load better. Definitely stick with factory motor mounts, altho I think you would see a benefit out of a solid tranny mount without any real detrimental side effects (aside from feeling the road through your shifter...).

Regards,

Dave E

Since the entire drivetrain is supported by only three points, two engine mounts and the transaxle mount, if a solid transaxle mount is used alone this will cause too much flexing of the stock crossmember that the transaxle hangs from. That piece of stamped steel will be trying to resist any movement of the drivetrain all by itself, and will likely cause fatigue cracking in that piece. Either replace all 3 mounting points or leave them all stock would be my thoughts

User 41221

Hence my original warnings about running race oriented stuff on a street car! lol Yes, Dave is right, altho I would be inclined to think that the mount would be able to resist the fatigue cracking, as the ones I have seen have all been overbuilt. I bet something else will experience extra wear, tho, as you will be transferring the load to that point.

Regards,

Dave E

The mount itself would be fine, it is the cross member above that the mount bolts to that would be suspect

dmoffitt

scott, re: delrin vs rubber, i'm not going to put any rubber parts on the car if i can help it - i've been looking at what i'd likely replace if anything, and i've yet to come up with much, besides perhaps the ons on the control arms (but, i dont know of anyone makeing delrin parts there). even that, i'm not sure about - i think i'm just going to get the car here, and see how it goes for at least a few days, and make a decision from there.

i too have heard that the transaxle mount can be run with standard motor mounts - i'm upgrading to a MUCH stiffer motor mount, it's not solid, but it's not the stock, seemingly sloppy ones. I think i'll inspect my stock transaxle mount and if it's in good shape, stick with it. if I have to replace it, I'll put in a solid one (like the kokeln one) - and keep careful watch on that tubular piece that the transmisison hangs from.

actually, i wonder if i could machine one out of a piece of delrin or poly? or does someone sell one like that?

User 41221

David,

You have mail...

Regards,

Chris Cervelli

I am sure that one lap at Sebring is worse than 10000 miles of Dave driving around upstate New York. Yes, the spherical bearings and solid mounts are going to make the car noisy, but they are not going to break from being driven on the street.

If you use good quality spherical bearings they pretty much never wear out. The bearings Porsche uses in the factory race cars are top notch and they just don't wear out. I used bearings like these when I built the #41 car. Crappy bearings wear out driving around the paddock. Don't get me started on plastic bushings.

As far as dirt goes, no street car could be as dirty as a race car that completes a half wet-half dry 24hrs of Daytona. Those bearings survive that ok.

A solid trans mount in a 944 is not too bright. I am all for solid mounts, but the 944 is a special case:

A fast 944 racer will need solid engine mounts so the P/S pulley does not rub the lower radiator hose. If you install a solid trans mount along with solid engine mounts, you are now trying to constrain the thermal expension of an 8 foot long engine-torque tube-transmission assembly with the transmission mount. That expansion is going to break something, guaranteed.

Plus, unlike an old 911, the shifter in a 944 is mounted entirely on the drivetrain, so even if the assembly moves around a little, shifting won't be affected at all.

User 41221

Chris, you would be a good one to answer this question. My point has never been that the spherical bearings would wear out, but that the loads would be transferred to the next weakest link, causing failures in places other than where the loads were originally designed to be carried. On a race car, this isn't necessarily a concern, due to lessened weight and the frequency in which race cars are torn down, rebuilt and driven fewer miles than a regularly driven street car. On a regularly driven street car, with the added weight of street glass, interior components and accessories, you are talking a significant amount of extra load, and compounded by the spikes in load caused by hitting potholes, expansion joints etc. The question is, don't you think you would be seeing failures in the mounting points of various suspension components? If not, I may rethink a few of my ideas on how I want to set up my car!

Regards,

Chris Cervelli

I don't think the car weight is really an issue. The loads into the suspension will be far higher on a race car because the tires are so much better.

A good example of this is breaking CV joints and clutches. As soon as I put slicks on the CV joints would last only one weekend. I broke a Turbo Cup clutch disc after only four hours use. Prior to the slicks, these parts had a more reasonable life span.

I am not suggesting anyone install spherical bearings in a street car. The performance benefit on the track is pretty minimal compared to all the other things you can do without impacting the ride comfort so much.

I don't put spherical bearings on anything but an all out racer. The stock rubber bushings do a very good job until you are fighting for that last .1 second in lap time.

Porsche runs a few spherical bearings in the GT2 and GT3 street cars. I guess they feel that the increased performance outweighs the extra noise.

Plastic bushings are pretty much a total disaster. Polyurethane is really bad and Delrin is not quite so bad because it is so tough. These plastics don't squish and flex like rubber. They very quickly wear or beat out. There are some places a plastic bushing can work okay but a 944 does not have any of these special cases.