what boost to N/A pistons explode?

[marcoze]

Well, once i get the van up and running i want to build a bigger better more race oriented motor for an Omni or Horizon. I was thinking of running some n/a pistons on T2 Rods and running 110 unleaded race gas mixed with some good 93.

Who has experience of seeing what point these pistons fragment?

[Ben Paquin]

Quote:

Originally Posted by marcoze Well, once i get the van up and running i want to build a bigger better more race oriented motor for an Omni or Horizon. I was thinking of running some n/a pistons on T2 Rods and running 110 unleaded race gas mixed with some good 93. Who has experience of seeing what point these pistons fragment?

It's not worth trying. If you are going to use T2 rods, at least use factory Mahle T2 pistons.

[marcoze]

Quote:

Originally Posted by Ben Paquin It's not worth trying. If you are going to use T2 rods, at least use factory Mahle T2 pistons.

You dont think so? I think that if i ran race gas and an intercooler i could run it at about the same boost levels as a turbo piston motor. Just from my experience with n/a motors....more compression= more power.

[Ben Paquin]

Quote:

Originally Posted by marcoze You dont think so? I think that if i ran race gas and an intercooler i could run it at about the same boost levels as a turbo piston motor. Just from my experience with n/a motors....more compression= more power.

The T2 piston is made by mahle and is definately sturdier.
Some engines seems to really engine more compression. However these engines are little strokers. And they tend to already have a very high peak torque. That alone tends to make them prone to detonation compared to an engine that "winds" more like a Honda or even a 4G63.
Doesn't mean it can't work but the tuning will have to be great and at high boost you will absolutely need race fuel.

All in all I wouldn't go more than 8.5 : 1 in these engines at high boost. Unless of course you manage to get a powerband from 5-7K rpm. Stock these engines have a powerband from 4.5-5.8K for the 2.2 and 4K-5.3K for the 2.5.

[turbovanman]

If you use 110 and watch your spark curve, you should be fine. Mine melted at 12psi intercooled with 89 octane, but I was set up for turbo pistons at the time. I would change the rods though to T1 or T2's for added durability. Putter is running n/a and he's been fine so far!

[Timmay2]

I run 12 or so PSI , intercooler, on stock bottom end but with a ghead to help lower compression abit.. run on pump 91 octane with no problems yet DO IT!

[marcoze]

If i am going to do this, it will be on a Nice set of Crower rods. And i would get the n/a pistons Cryo treated for some added strength. I wish someone make N/A Forged pistons for this motor, that would be awesome.

[turbovanman]

Quote:

Originally Posted by marcoze If i am going to do this, it will be on a Nice set of Crower rods. And i would get the n/a pistons Cryo treated for some added strength. I wish someone make N/A Forged pistons for this motor, that would be awesome.

I hate to plug FM after all they crap they put me thru but they list N/A hi-po stuff, maybe check them out?

[Putter]

I've run the higher C/R's without a ton of problem, but I wouldn't go out of my way to do it, in fact I'm dropping compression with new pistons right now. It works but its definatly not the best option for a street motor. As far as a full race motor, I wouldn't be one to contribute because I don't know when the flat tops fail. Might consider turbo pistons milled flat with a longer rod instead if you're looking for that 'race' motor. But the factory flat tops yeild alot of compression.

I think the Fuel Injected N/A pistons had a slight dish in them, as my carb n/a pistons only have valve relief.

The most detonation free boost I could get out of my flat tops unintercooled was about 10psi on 92 octane. If you're going to do it for a race only motor, skip mixing 92 octane in with anything if you're going to try to run alot of boost. Your effective compression ratios really start going up quick with 9.5:1 and 10+ boost....so if you try it use good fuel.

[Una]

I saw a set of forged flat tops up on Ebay about 2 weeks ago.. And I think I saw someone selling a similar set in the forums here right after that.