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-   -   3/8" rod bolts vs RPM (https://classracer.com/classforum/showthread.php?t=50122)

bruce69camaro 10-28-2013 08:25 AM

3/8" rod bolts vs RPM
 
I have a 408 bbc with 3/8" ARP rod bolts.

This motor is still new with only 8 runs on it.

I was shifting at 6000 rpm but it was still pulling.

I'm using a P/G with 4.57's and 14" x 32" slicks.

Can I get away with shifting in the 7000-7200 rpm range?

Thank you.

1320racer 10-28-2013 02:53 PM

Re: 3/8" rod bolts vs RPM
 
Bruce, no one can give you any guarantees, even the best rods and bolts break, ask me how I know.;)

Will your engine stay together for the occasional drag strip run shifting at 7000, probably yes.

Would I bracket race this combo competitively, turning that RPM with those bolts? NO

bruce69camaro 10-29-2013 06:35 AM

Re: 3/8" rod bolts vs RPM
 
Thanks Ed......

HP HUNTER 10-29-2013 10:24 AM

Re: 3/8" rod bolts vs RPM
 
Quote:

Originally Posted by bruce69camaro (Post 406196)
I have a 408 bbc with 3/8" ARP rod bolts.

This motor is still new with only 8 runs on it.

I was shifting at 6000 rpm but it was still pulling.

I'm using a P/G with 4.57's and 14" x 32" slicks.

Can I get away with shifting in the 7000-7200 rpm range?

Thank you.

That would depend on: how much the pistons weigh, and how the rods were prepped, and how you slow down past the lights, and the big one if the rods were pressed, how much press was on the pin.

bruce69camaro 10-29-2013 10:40 AM

Re: 3/8" rod bolts vs RPM
 
The pistons are TRW L2287F, which I was told weighs a lot, they are full floating pistons and the rods were polished and balanced, if that matters.

As for slowing the car down after the line, I would take my foot off the pedal, slow down the car and then bump it into neutral, which is another question. I was told this is not a good idea to do with a P/G, agree or disagree?

1320racer 10-29-2013 11:34 AM

Re: 3/8" rod bolts vs RPM
 
Bruce, based on your parts selection, stock rods and trw replacement pistons, you obviously did not build this engine for competitive bracket racing. I stand by my advice.

As to neutraling the trans after the stripe, only if you want to put your very nice car into the wall and/or on it's roof!

bruce69camaro 10-29-2013 11:57 AM

Re: 3/8" rod bolts vs RPM
 
Ed, your right, this was not a "true" race motor build, but I had to start somewhere and from our past conversations, I think you know why I had to use these parts.

Speaking of "him", this was the first time he came to a race and he had a blast and he is now asking when we are going back.

I hear your words and I'll keep it in gear from now on....we don't need anymore family issues!

I'd like to think this motor will be a learning step for what "not" to do on any future builds.

Thank you.

1320racer 10-29-2013 11:59 AM

Re: 3/8" rod bolts vs RPM
 
Bruce, I do and understand.

You have a PM.

HP HUNTER 10-29-2013 10:13 PM

Re: 3/8" rod bolts vs RPM
 
Quote:

Originally Posted by bruce69camaro (Post 406404)
The pistons are TRW L2287F, which I was told weighs a lot, they are full floating pistons and the rods were polished and balanced, if that matters.

As for slowing the car down after the line, I would take my foot off the pedal, slow down the car and then bump it into neutral, which is another question. I was told this is not a good idea to do with a P/G, agree or disagree?

I agree with Ed.

bruce69camaro 10-30-2013 07:06 AM

Re: 3/8" rod bolts vs RPM
 
Thank you for all your advice.....


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