And as posted above, I would have the rev limiter set well below 7,000.
Underdrive Pulleys and Crank Pinning
Thread Starter
Safety Car
Joined: May 2006
Posts: 3,799
Likes: 1
From: Northern Virginia
St. Jude Donor '08
Underdrive Pulleys and Crank Pinning
Did a search but did not find info I was looking for.
I have a 99 FRC that will be street-driven only. No racing of any sort.
I am doing a heads/cam over winter.
Want to replace the harmonic balancer/pulley. No supercharger in my future.
Questions:
Should I stick with stock size pulley or get underdrive pulley, and if so, what size? I am concerned that if I get too much under drive my a/c, cooling, and electrics won't work properly.
Should I pin the crank? New cam will allow me to spin to 7000 rpms. What pinning kit would you recommend?
Thanks
I have a 99 FRC that will be street-driven only. No racing of any sort.
I am doing a heads/cam over winter.
Want to replace the harmonic balancer/pulley. No supercharger in my future.
Questions:
Should I stick with stock size pulley or get underdrive pulley, and if so, what size? I am concerned that if I get too much under drive my a/c, cooling, and electrics won't work properly.
Should I pin the crank? New cam will allow me to spin to 7000 rpms. What pinning kit would you recommend?
Thanks
Advanced
Joined: Aug 2005
Posts: 97
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MTI Underdrive Pulley
Anytime you do a cam swap an underdrive pulley is always a good idea. I have a MTI 20% underdrive pulley I'll sell you including belts for $150 shipped. This setup has less than 1000 miles on it and I guaratee its quality and condition. I went forced induction is the only reason I'm getting rid of this setup. Paid $300 originally. P.M. me if interested.
Safety Car
Joined: Sep 2003
Posts: 3,558
Likes: 2
From: Cape Coral FL
SLP is also making a nice UD pulley. If you are putting it on for the first time you should be ok provided you use the recommended technique. You will probably want to pin it if using a used pulley or if you take it off and reinstall. When you do a h/c upgrade you will typically up the idle a bit anyway. I would caution against spinning to 7000 rpm on a 99. The rod bolts have been determined to be the weak link until 2001 when they upgraded them.
Last edited by ArKay99; Dec 17, 2007 at 10:38 AM.
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Let me understand this, you have a 99 FRC with a 6 speed and your going to to heads and cam and never race it at all????????????
OK, just to be on the safe side PIN THE CRANK!!!!!!!!!!!!
OK, just to be on the safe side PIN THE CRANK!!!!!!!!!!!!
Team Owner
Joined: May 2005
Posts: 23,682
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From: Flagstaff Az.
Thread Starter
Safety Car
Joined: May 2006
Posts: 3,799
Likes: 1
From: Northern Virginia
St. Jude Donor '08
SLP is also making a nice UD pulley. If you are putting it on for the first time you should be ok provided you use the recommended technique. You will probably want to pin it if using a used pulley or if you take it off and reinstall. When you do a h/c upgrade you will typically up the idle a bit anyway. I would caution against spinning to 7000 rpm on a 99. The rod bolts have been determined to be the weak link until 2001 when they upgraded them.
Thread Starter
Safety Car
Joined: May 2006
Posts: 3,799
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From: Northern Virginia
St. Jude Donor '08
Here is a link.
http://www.radicalnorthamerica.com/index.asp
Older versions of the Radical Prosport can be purchased for around $25K used.
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Safety Car
Joined: Sep 2003
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From: Cape Coral FL
One word of caution here. Spinning to 7000 on a stock bottom end isn't too safe for other reasons. One issue is main bearing oil starvation causing them to spin. Another issue is valve train stability and float on the top end. If you want to build it for those rpm's you may want to forge the bottom end and if staying with hydraulic rollers get the Cadillac Racing lifers and use very light weight valves with stout springs and rockers to match. Also, you may want to wrap the bell housing with a blanket. If something in the clutch lets loose at that rpm, you could lose your legs, or worse.
Thread Starter
Safety Car
Joined: May 2006
Posts: 3,799
Likes: 1
From: Northern Virginia
St. Jude Donor '08
One word of caution here. Spinning to 7000 on a stock bottom end isn't too safe for other reasons. One issue is main bearing oil starvation causing them to spin. Another issue is valve train stability and float on the top end. If you want to build it for those rpm's you may want to forge the bottom end and if staying with hydraulic rollers get the Cadillac Racing lifers and use very light weight valves with stout springs and rockers to match. Also, you may want to wrap the bell housing with a blanket. If something in the clutch lets loose at that rpm, you could lose your legs, or worse.
I am not going to do anything stupid. My brother won't let me.
I bought an ECS N/A cam and also have a set of ported and polished LS1 heads with springs good to 650 lift.
I am doing a number of things to ensure the reliability of the motor as I do not want to blow it.
ECS will be tuning the car and I will ask them to tune so I don't have any issues. The reason I mentioned the 7000 rpm limit is because the cam's power range is from 3000 to 7000 rpm.
Have a textralia clutch with the lightweight steel billet flywheel so hopefully I won't have to worry about a blown clutch.
I am not planning on hitting the high rpms routinely but I do like to let loose once in a while.
Racer
Joined: Sep 2000
Posts: 373
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From: Wakefield R.I.
Because you are there already PIN THE CRANK and do the ud pulley(25% - you will have no A/C or alternator issues). BTW the SLP is a Powerbond for XX $ more, a really nice piece.
I would also look around for a set of 243 heads. They are out there for cheap money.
I would also look around for a set of 243 heads. They are out there for cheap money.
Race Director
Joined: Oct 2002
Posts: 16,477
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From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
FYI, the SLP pulley is the same identical unit as the Powerbond. Same mfr, same exact product.
The SLP typically sells for $30-40 more than the Powerbond brand, so all you're paying more for is the SLP box it comes in.
I bought my 25% Powerbond from Texas Speed for $199 last year..was the best price I found at the time. It's a very nice quality part.
Also, for the OP, note the Powerbond/SLP pulleys do not underdrive the a/c at all. You use the stock length a/c belt. The ASP unit underives the a/c by 10%.
The SLP typically sells for $30-40 more than the Powerbond brand, so all you're paying more for is the SLP box it comes in.
I bought my 25% Powerbond from Texas Speed for $199 last year..was the best price I found at the time. It's a very nice quality part.
Also, for the OP, note the Powerbond/SLP pulleys do not underdrive the a/c at all. You use the stock length a/c belt. The ASP unit underives the a/c by 10%.
Pro
Joined: Aug 2002
Posts: 688
Likes: 58
From: Freeburg IL
Cruise-In IX Veteran
I'm actually in the middle of this now (waiting on pin kit and install tool to finish up). Summit racing actually makes a SFI approved 25% UD balancer for c5s now for like 150. I got one and am impressed as heck with the quality of it. The AC on it uses the factory size pulley, only the acc is UD. I decided to pin just for the added piece of mind, I don't want to have to pull that rack again!
Get an install tool in advance or you'll be like me waiting
I ordered this one, proven and I didn't have to search for the pieces.
http://www.ls1tech.com/forums/showth...883&highlight=
Good luck!
Get an install tool in advance or you'll be like me waiting
I ordered this one, proven and I didn't have to search for the pieces.
http://www.ls1tech.com/forums/showth...883&highlight=
Good luck!
Last edited by JCSZ51; Dec 17, 2007 at 08:03 PM.
Melting Slicks
Joined: Jan 2003
Posts: 2,056
Likes: 0
From: monroe city mo
I had heads & cam done 8 months ago.They did not pin the crank. I ended up having to tear it down & pinning it myself because the underdrive pulley worked out 1/4 of an inch. I called the vendor and was told they didnt pin cranks then,but they do now. I used the A&A kit. Pin it now,or pin it later!
Thread Starter
Safety Car
Joined: May 2006
Posts: 3,799
Likes: 1
From: Northern Virginia
St. Jude Donor '08
^^Thanks for all the great info. Will look into the Summit Racing pulley. Why pay more for the same thing?
The ported and polished LS1 heads that I have will seriously outflow a set of stock 243 heads.
The ported and polished LS1 heads that I have will seriously outflow a set of stock 243 heads.
i pinned this thread! 