IHADAV8.com - Turbo Buick Tech, and Nonsense

Tech Area => General Buick Tech => Topic started by: Scoobum on July 07 2013, 09:24:17 PM

Title: Stock Bottom End RPM Limit
Post by: Scoobum on July 07 2013, 09:24:17 PM: How much RPM can a stock bottom end 109 engine survive to?
Title: Re: Stock Bottom End RPM Limit
Post by: Steve Wood on July 07 2013, 11:45:35 PM: One of mine has been to 6200 quite a few times
Title: Re: Stock Bottom End RPM Limit
Post by: Scoobum on July 07 2013, 11:49:12 PM: PL has me going through the traps at 5850 at 23 PSI. Any idea what the RPM's would be at 28 PSI? Steve...what cam are you using to achieve that 6200 RPM?
Title: Re: Stock Bottom End RPM Limit
Post by: Steve Wood on July 07 2013, 11:57:01 PM: No idea...I am using a 210/210 roller....at 6201 it backfires once like it blew up when one of the lifters pumps up-or at least one

I normally try to shift at 5900-6000

I have always wondered when it was going to drive over the crank
Title: Re: Stock Bottom End RPM Limit
Post by: PacecarTA on July 08 2013, 12:11:29 AM: i was shifting 6300 for a time on stock bottom trapping a little over 6000 running out the 1320
Title: Re: Stock Bottom End RPM Limit
Post by: motorhead on July 08 2013, 10:14:53 AM: Yeah, the heads/cam are the biggest limitation here not the short block, engine speed or boost pressure. As long as you are getting the typical 10psi/1000rpm oil pressure ratio you should be fine spinning it to 6000rpm.
Title: Re: Stock Bottom End RPM Limit
Post by: Steve Wood on July 08 2013, 10:32:33 AM: Does not hurt to recall how small/old the rods are and how many cycles are on the crank in the past 27 years...someth ing can break while backing out of your garage
Title: Re: Stock Bottom End RPM Limit
Post by: Scoobum on July 08 2013, 10:47:16 AM: Rods are new...hard to say with the crank how hard it had been beat on...had it magnufluxed was the best I could do...and the rotating assembly balanced.
Title: Re: Stock Bottom End RPM Limit
Post by: Steve Wood on July 08 2013, 10:55:35 AM: We all know two things. The faster we go, the more it costs and the faster we go, the quicker something breaks which is the reason it costs more to go fast in the first place! :D
Title: Re: Stock Bottom End RPM Limit
Post by: larrym on July 13 2013, 01:14:40 PM: what sort of timing do you guys run when you spin it that high? Mine shifts around 5800 maybe 6000 1-2
I have the timing on the Gen2 set at 20 degrees with 25lbs of boost no knock yet should I keep adding timing until I see knock then pull a couple degrees out or smile and be happy with what I got :P

I think the 25 PSI is the sweet spot for my CPT 61 I did a couple pulls at 26 PSI but didn't see much of a difference if any.
Title: Re: Stock Bottom End RPM Limit
Post by: Steve Wood on July 13 2013, 03:18:15 PM: depends on your combination... but yes, add a little timing at a time just like any other tune
Title: Re: Stock Bottom End RPM Limit
Post by: larrym on July 13 2013, 08:41:14 PM: Well I'm at 21 degrees still not knocking my TT chip had 25 degrees in 1st 23 for the rest. Looks like I'm going to get close to the old set up. Time for another gallon of alky and head for the tuning road I'm luck my place has a 4 lane strip no homes just have to watch for deer can open it up.