L98 RPM considerations
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
L98 RPM considerations
I tried this thread on scan & tune but after 30 views, no input from anyone?? Perhaps my question is too detailed?
I'm looking for input/thoughts on what the bottom end of a stock '90
L98 should be capable of/safe with RPM wise?
My thought is that my larger than stock intake system should be able to flow & produce power beyond where the stock engine drops off.
My intake setup consisting of:
TPIS BM intake/runners/matched plenum/52MM TB
113 Heads w/ cleaned up & matched intake ports to the BM, new HD valve springs, light port & polished exhaust ports, 1.6 rockers & of course D1 Procharger currrently at 8.5 psi.
My bottom end has new cam bearings, new rings, new double roller timing set, but stock pistons, new oil pump & a nice canton 7qt pan.
I would think the intake should support up to 6000 RPM but I currently have my rev limiter a little below 5500 as before the SC install, this same setup had power dropping off pretty hard after 5000.
Am I asking for trouble letting it run closer to 6k now? Or is there anything even to be gained there??
TIA
I'm looking for input/thoughts on what the bottom end of a stock '90
L98 should be capable of/safe with RPM wise?
My thought is that my larger than stock intake system should be able to flow & produce power beyond where the stock engine drops off.
My intake setup consisting of:
TPIS BM intake/runners/matched plenum/52MM TB
113 Heads w/ cleaned up & matched intake ports to the BM, new HD valve springs, light port & polished exhaust ports, 1.6 rockers & of course D1 Procharger currrently at 8.5 psi.
My bottom end has new cam bearings, new rings, new double roller timing set, but stock pistons, new oil pump & a nice canton 7qt pan.
I would think the intake should support up to 6000 RPM but I currently have my rev limiter a little below 5500 as before the SC install, this same setup had power dropping off pretty hard after 5000.
Am I asking for trouble letting it run closer to 6k now? Or is there anything even to be gained there??
TIA
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
With that intake, I would run to 52-5400RPM. If you moved to a SR, then 5800, and a MRII would get you past 6000. If you want more power, drop the pulley size and move the idler towards the blower pulley.
The bottom end will survie a significant amount of power if the tune is "on".
Aaron
p.s. What cam are you running? That may be part of the engine falling off at 5000.
The bottom end will survie a significant amount of power if the tune is "on".
Aaron
p.s. What cam are you running? That may be part of the engine falling off at 5000.
Intermediate
Joined: Apr 2000
Posts: 47
Likes: 0
From: Woodstock IL
Before I built my 383, I was shifting my stock 89 L98 at 5800-6000 without a problem. I was running 8-9lbs of boost. The engine was going strong till I rebuilt it.
Last edited by ED89; Nov 24, 2006 at 12:22 PM.
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Originally Posted by ED89
Before I built my 383, I was shifting my stock 89 L98 at 5800-6000 without a problem. I was running 8-9lbs of boost. The engine was going strong till I rebuilt it.
Aaron
