Care to review my geometry?
11-07-2002, 09:29 AM
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Care to review my geometry? I recently added MTI S2 LS1 heads and X1 cam, along with some other things (double row chain, spark plugs, chromo pushrods, etc). It doesn't feel as strong as it should. I have not tuned, and will be on the dyno in a few weeks to do so, but I want to check into anything I can before that.
One thing I'm wondering about is my geometry:
Heads milled "cleanup only" (want to keep CR low for supercharger). Less than .010 milled off.
Installed stock length chromoly pushrods
Did not use rocker shims due to very little milling.
Pretty sure the Comp cams typically have a .030 smaller radius than stock.
Valvetrain is VERY loud. No SES or major misfires or anything, but I'm wondering if I'm hurting my power with preload. MTI said I should be fine, but I want some more opinions or insight.
Ran at the track, NO launching due to stock rear end, (feathered out clutch from 1k rpm) and pulled 2.4 60', but I expected that due to not launching. Ran a 13.6 @108 or 109. Even though I was taking it very easy and on stock F1s, this seemed poor to me, since the track was hooking really well.
Like I said I'll be dynoing and tuning, just curious if the valvetrain math adds up to others.
-Dave
One thing I'm wondering about is my geometry:
Heads milled "cleanup only" (want to keep CR low for supercharger). Less than .010 milled off.
Installed stock length chromoly pushrods
Did not use rocker shims due to very little milling.
Pretty sure the Comp cams typically have a .030 smaller radius than stock.
Valvetrain is VERY loud. No SES or major misfires or anything, but I'm wondering if I'm hurting my power with preload. MTI said I should be fine, but I want some more opinions or insight.
Ran at the track, NO launching due to stock rear end, (feathered out clutch from 1k rpm) and pulled 2.4 60', but I expected that due to not launching. Ran a 13.6 @108 or 109. Even though I was taking it very easy and on stock F1s, this seemed poor to me, since the track was hooking really well.
Like I said I'll be dynoing and tuning, just curious if the valvetrain math adds up to others.
-Dave
11-07-2002, 10:39 AM
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Re: Care to review my geometry? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Chris Spiess:
<strong>Just for comparison...my stock internal 98 w/o headers traps 109. I'd say you have some serious issues to resolve.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well I wasn't pushing it hard so I don't think my times were terribly indicitive of final performance, but I still think its a little low.
-Dave
<strong>Just for comparison...my stock internal 98 w/o headers traps 109. I'd say you have some serious issues to resolve.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well I wasn't pushing it hard so I don't think my times were terribly indicitive of final performance, but I still think its a little low.
-Dave
11-07-2002, 04:08 PM
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Re: Care to review my geometry? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Ragtop 99:
<strong>what is your exhaust set-up?
What mph did you run before heads & cam?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">SLP LT headers, highflow cats, and SLP LM muffler. Ran 13.2 @ 109 before, best of 2.1 60 foot.
-Dave
<strong>what is your exhaust set-up?
What mph did you run before heads & cam?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">SLP LT headers, highflow cats, and SLP LM muffler. Ran 13.2 @ 109 before, best of 2.1 60 foot.
-Dave
11-07-2002, 09:54 PM
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Re: Care to review my geometry? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by DaleMX:
<strong>If you took .010 off the heads, and the cam BC was .030 smaller than stock then you have .020 less preload than stock.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah, I asked MTI if I should shave off .020 from my rocker mounting plates, they said it should be fine. I guess .020 isn't that much, but wasn't sure. Thought it might help reduce the sewing machine noise a bit though. The rockers sit pretty well on the middle of the valve stem, but I should look again now that its got a couple hundred miles.
-Dave
<strong>If you took .010 off the heads, and the cam BC was .030 smaller than stock then you have .020 less preload than stock.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah, I asked MTI if I should shave off .020 from my rocker mounting plates, they said it should be fine. I guess .020 isn't that much, but wasn't sure. Thought it might help reduce the sewing machine noise a bit though. The rockers sit pretty well on the middle of the valve stem, but I should look again now that its got a couple hundred miles.
-Dave
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11-08-2002, 08:55 PM
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Re: Care to review my geometry? Looks like a good thread on the subject.
https://ls1tech.com/ubb/ultimatebb.p...c;f=1;t=007693
Dale
<small>[ November 08, 2002, 08:57 PM: Message edited by: DaleMX ]</small>
https://ls1tech.com/ubb/ultimatebb.p...c;f=1;t=007693
Dale
<small>[ November 08, 2002, 08:57 PM: Message edited by: DaleMX ]</small>
11-08-2002, 09:15 PM
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Re: Care to review my geometry? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by DaleMX:
<strong>Looks like a good thread on the subject.
https://ls1tech.com/ubb/ultimatebb.p...c;f=1;t=007693
Dale</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yep, read it earlier, pretty much set my mind at ease. Like I said MTI assured me the .020 diff is no biggie, just wanted to double check. The valvetrain certainly is loud, but at .591 lift what do you expect?
-Dave
<strong>Looks like a good thread on the subject.
https://ls1tech.com/ubb/ultimatebb.p...c;f=1;t=007693
Dale</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yep, read it earlier, pretty much set my mind at ease. Like I said MTI assured me the .020 diff is no biggie, just wanted to double check. The valvetrain certainly is loud, but at .591 lift what do you expect?
-Dave
11-09-2002, 06:50 AM
#10
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Re: Care to review my geometry? Higher valvespring pressure and i assume XER lobes on X1 will make valvetrain much noisier.
As for stock rear end if you have Zexel Torsen rear you can leave a lot harder than you think! I have cut 1.81 60 ft. on Hoosiers at 3550 lbs, dumping clutch at 4000rpm! Thats not great but it sure beats walking the car out to save the rear end! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
As for stock rear end if you have Zexel Torsen rear you can leave a lot harder than you think! I have cut 1.81 60 ft. on Hoosiers at 3550 lbs, dumping clutch at 4000rpm! Thats not great but it sure beats walking the car out to save the rear end! <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />