Low compression pistons ...

peer648

Member
Mar 4, 2010
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Québec
Rebuilding the motor, forged internals, port and polish head,supporting mods. Like 500whp to 600whp. The motor is totaly disemble. The one who's doing my motor offer's me to take low compression pistons 8,2:1. Hard to find and the ones he found aren't cheap!!! So my question his, Do I really need this? and Will I see the difference?
 

suprarich

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Nov 9, 2005
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ohio
What ECU and fuel will you use? I can see nothing but slight loss in all the things you would want a mid level motor to do by using such a low compression piston.
 

peer648

Member
Mar 4, 2010
49
0
6
Québec
For now I got Hks pfc fcon with fcd, but i got the whole winter, may change for aem ems. Fuel, ain't done yet. I got a AFPR, no fuel pump yet(need tip on that, to aproach the 600whp,will a walbro 255lph do the job and would a bosch 300lph be a good one,haven't heard about someone having bosch.). This winter maybe buy a SP67 to run 25 psi. Its about that. Thanks for help
 

suprarich

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Nov 9, 2005
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Off the shelf 8.4 to 9.0:1 pistons would be fine for your set up. No need for a custom made piston.

If you can afford it. the AEM would be a better idea than the piggyback controllers. A single Walbro is not going to do 600 whp. The bosch pump flows 300lph and would be a better pump for your power, but you will still be near the threashold. Twin walbro pumps in the tank or better yet, two external bosch pumps running together with the AEM switching the 2nd pump on at a preset level of need.
 

peer648

Member
Mar 4, 2010
49
0
6
Québec
Alright, so i'm taking the pistons with 8,4:1 of CR and 0.040 oversize. 2mm headgasket to lower the compression a bit
 

northwestsupra

New Member
Sep 19, 2006
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Washington, Marysville
suprarich;1616554 said:
Off the shelf 8.4 to 9.0:1 pistons would be fine for your set up. No need for a custom made piston.

If you can afford it. the AEM would be a better idea than the piggyback controllers. A single Walbro is not going to do 600 whp. The bosch pump flows 300lph and would be a better pump for your power, but you will still be near the threashold. Twin walbro pumps in the tank or better yet, two external bosch pumps running together with the AEM switching the 2nd pump on at a preset level of need.


Was told once by a wise man on the forum. "What's the point of running two pumps. If one fails and you go to boost say bye bye motor. If you run one big pump engine will run noticeably different of not at all" it was duane I think that said that. But could have been ij. Either way single pump all the way. I'm running a areomotive a1000 external.

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suprarich

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Nov 9, 2005
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ohio
northwestsupra;1616809 said:
Was told once by a wise man on the forum. "What's the point of running two pumps. If one fails and you go to boost say bye bye motor. If you run one big pump engine will run noticeably different of not at all" it was duane I think that said that. But could have been ij. Either way single pump all the way. I'm running a areomotive a1000 external.

Sent from my Droid using Tapatalk

A single pump can half fail and lean your motor just as easy as a dual pump system can have one pump fail. Why would you assume that someone who may run a staged dual pump set up would not have a fail safe system in place? A fail safe is much safer than your single pump.
 

northwestsupra

New Member
Sep 19, 2006
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0
Washington, Marysville
suprarich;1617185 said:
A single pump can half fail and lean your motor just as easy as a dual pump system can have one pump fail. Why would you assume that someone who may run a staged dual pump set up would not have a fail safe system in place? A fail safe is much safer than your single pump.

Just quoting someone lol. But you can't stop failure it happens when it happens

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