Chris’s 2007 SS/SC track frame build for autocross

ccannx

Goblin Guru
The other reason you had to increase the spring rate is you lowered the instan roll center with the upper control arm. making more load on the spring. Maybe make a 1/2" rear bar and lower the spring rate.
Brad
Also lost some travel in the rear but it feels like travel is more important in the front. Added stiffer setting on FSB for next test and tune at Richmond raceway.
 

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Torchandregdoc

Goblin Guru
No it is the number of degree the wheel goes negative a the suspension moves up. This keeps the tire at the correct angle with the road as the body rolls in a turn.

Brad
Written communication is not my strong suit. I have wondered how much squat you get with 150's on the rear. I assumed when you asked the camber change over 2" of travel that, you were questioning the length of the upper control and its affect on camber exiting corners? The loose issue.
 

George

Goblin Guru
The amount of squat is determined by spring rage and the anti squat geometry of the rear suspension which with his modification could be adjusted with a little modification to the inner upper control arm mounts. You want the rear suspension to be supple enough so that it bits on take off but has the correct amount of roll resistance.

Brad
 

Dale E

Well-Known Member
I asked Chris to post his rear suspension build after he answered a PM I sent him and a few others. Thanks to Ross for uploading the video to his channel. This is on the 3800 SC V6 I posted about in another thread. Fixed cut PCV for testing. The tie rod pcv is attached to the bolt on the frame and the upper pcv is actually attached to a bolt hole on the engine block. It was just testing a theory, so not to strict measurements. I like playing!


Dale
 

ccannx

Goblin Guru
My cheesy exhaust was too loud. Last autocross I could see the starter covering his ears every time I took off. Was hoping the turbo kit would make it more tolerable. Fashioned a new exhaust from speedway stock parts. All 3 inch 1 U 1 90 and a chambered muffler. Added 1 isolator on the rear passengers side for extra support.. Sounds much better.
 

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ccannx

Goblin Guru
Car did great today until the last run. I got some sputtering and then some oil burning. Limped it back to the trailer and it appears to have blown the dipstick out. Oil also looks to be coming from the head gasket by the tensioner. Maybe the oil seal in the turbo also went out. Not sure it will take some digging.

I'm not super interested in buying a new k04 when you can get an entire motor with a turbo for 2k but not sure with what is evolved with the new ecu and wiring harness moving from an lsj. I could just move over to megasquirt.

The suspension modifications have worked well but not fast enough for an FTD. There was a pretty zippy turbo miata I was not able to catch either of the drivers. Someone had mentioned it weights 1200lbs which is pretty unbelievable (most likely 2200 as its run in xp)This was unfortunately my first dry event with the turbo working correctly and was not able to get the times down fast enough before the failure.
 

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Desert Sasqwatch

Goblin Guru
Hmm, 1200lb Miata is a stretch - even if it had speedholes! Sorry to hear about the mechanical issue, hope it's not too serious. Looks like you were turning in some good time too.
I need to ask how the new rear suspension is working out? Can you give us some comparison info? I know Dale is probably asking you the same thing.
 

ccannx

Goblin Guru
Hmm, 1200lb Miata is a stretch - even if it had speedholes! Sorry to hear about the mechanical issue, hope it's not too serious. Looks like you were turning in some good time too.
I need to ask how the new rear suspension is working out? Can you give us some comparison info? I know Dale is probably asking you the same thing.
I don't believe it either, but it was pretty darn fast lol.

Its run in XP being turbo and rwd its minimum weight has to be at least 1900lbs.
 

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ccannx

Goblin Guru
The suspension is doing very well. The rear is biting better out of the corner. Almost zero bumpsteer. Car is completely controllable even when putting down gobs of power. Taking Ackerman out of front helped with that also.
 

Desert Sasqwatch

Goblin Guru
Should be, as long as the cylinder wall is not scored badly. The piston looks a little cooked to, maybe it went lean for some reason - check the fuel injectors. Lots of new parts and elbow grease will get you freshened up motor to play with again. :)
 

Ross

Goblin Guru
Did the cracked piston score the bore?
Is the head flat? Or is there enough aluminum left to allow for re-flattening?
If you pass those tests, usually you are good.
Clean up the parts, and do close inspection at a machine shop, or do it yourself, is the best bet.
They sell color dies for inspecting for cracks. I have had good luck with DIY color dies, and successfully found & repaired a crack in my oil pan.
 

ccannx

Goblin Guru
Did the cracked piston score the bore?
Is the head flat? Or is there enough aluminum left to allow for re-flattening?
If you pass those tests, usually you are good.
Clean up the parts, and do close inspection at a machine shop, or do it yourself, is the best bet.
They sell color dies for inspecting for cracks. I have had good luck with DIY color dies, and successfully found & repaired a crack in my oil pan.
Looks like the sleeve melted towards the bottom and the block behind it looks cracked.
 

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Lonny

Administrator
Staff member
I think the sleeves are removable and replaceable. Not positive though.
I saw in one of the cobalt shop manuals a tool for pulling the sleeves out.
 

Waterdriver

Goblin Guru
If the block casting is cracked, its junk.
Not sure if it's just the picture, but it looks like the cylinder isn't round anymore? Is that were you see a crack in the block? Behind this area?
20201022_181930.jpg
 

ccannx

Goblin Guru
If the block casting is cracked, its junk.
Not sure if it's just the picture, but it looks like the cylinder isn't round anymore? Is that were you see a crack in the block? Behind this area?
View attachment 17683
Yeah looks like the sleeve melted there and that is cracking in the aluminum block.

I read somewhere gen2 and 3 made improvements in this area with cooling and strength. The gen 3 LSJ bottom pictures on zzp's site look alot beefier around the sleeves.
 

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ccannx

Goblin Guru
Ordered a 60k mile B207r Saab motor off ebay for 680.47 shipped should be able to swap in a new timing set , LSJ cams and be good to go.
 
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