1100 Rpm @ Idle/ Bad For Xr Drives?
01-25-2005, 06:42 PM
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Re: 1100 Rpm @ Idle/ Bad For Xr Drives?
If you are the repair shop it not a bad problem. It won't kill it right away but will definatly make a loud niose when going into gear.
If a 572 has to idle that much, the cam must be too large for a bravo. Keep in mind, going into gear will loose 250 +- rpm. Will it need to idle at 1400 now?
I had a 244/252 cam, 112 lobe in a 572 that would idle at 950, in gear would be about 700. The lobe center is very important with idle. Cut back to a 100 or 108 lobe center will loose a lot more.
Most people over cam motors. A little little is much better that too much.
Hope this helped.
If a 572 has to idle that much, the cam must be too large for a bravo. Keep in mind, going into gear will loose 250 +- rpm. Will it need to idle at 1400 now?
I had a 244/252 cam, 112 lobe in a 572 that would idle at 950, in gear would be about 700. The lobe center is very important with idle. Cut back to a 100 or 108 lobe center will loose a lot more.
Most people over cam motors. A little little is much better that too much.
Hope this helped.
01-25-2005, 07:01 PM
#5
Re: 1100 Rpm @ Idle/ Bad For Xr Drives?
Though he's not building my engine this time, I was looking at the Chief Engine web site and noticed all of his 700+ hp engines he's posted 1100 or more rpm out of gear. That seems high to me. My 650hp ProCharged 454ci idled nice at 850 and 675 in gear.
01-25-2005, 08:20 PM
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Re: 1100 Rpm @ Idle/ Bad For Xr Drives?
Faster:
You should be OK. My old NA 632" had a 280/288 @.050 cam, 115 LSA solid roller that idled @1000-1100 and dropped to ~700 in gear. LSA is critical to idle quality! It still was a nasty cam that you could still feel loping at 4000
Motor ran awesome and accelerated like a raped ape.....Never any drive issues due to the idle. 
You should be OK. My old NA 632" had a 280/288 @.050 cam, 115 LSA solid roller that idled @1000-1100 and dropped to ~700 in gear. LSA is critical to idle quality! It still was a nasty cam that you could still feel loping at 4000
Motor ran awesome and accelerated like a raped ape.....Never any drive issues due to the idle.
Last edited by jdnca1; 01-25-2005 at 08:23 PM.
01-26-2005, 12:46 AM
#7
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Re: 1100 Rpm @ Idle/ Bad For Xr Drives?
I always thought about rigging up a momentary switch like a NOS button . Hook it up to a timing retard of a MSD timing retard module and retard the timing about 20-25 when ya shifted to lower the RPM . Cheaper than the interrupters 
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01-26-2005, 07:26 AM
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Re: 1100 Rpm @ Idle/ Bad For Xr Drives?
I had twin KE 675's with IMCO SC drives. When put into neutral they would spike up to 1100-1300 rps, and take 30 sec to come back down to about 1000rpms, never ran right. This is a definite way to NOT help your drives live, I went through 4 of them in 73 hours, TMP ended up fixing them. I have TMP 750 efi's, they idle at 750 rpms and run awesome, this is what you want. You need to stay in the 750-850 rpm range, make sure whom ever builds them can give yo a guarantee to this. Jeff
