11:1 turbo/nitrous - Honda Prelude Forum

sol95 · 11-08-2010, 06:10 PM

Very very very low boost maybe something like 7-8psi

Too late to exchange the pistons that cost me $600 (ross forged)

Already got the N20 kit so might as well throw it in there hehhe

11:1 sleeved motor
Darton sleeves (closed deck)
Daily Driver!!
AEM EMS2
Manley turbo tuff rods

I KNOW I KNOW, CR gonna be too high blah blah blah

what i'm i looking at as far as the HP? 7-8 psi? whats safe?

93 octane

mortifiedvictim · 11-15-2010, 08:16 PM

Honestly, you've made your N/A bed you might as well lay in it. If you were to boost would you be satisfied with a "safe" 2-4psi with a small/mid-size turbo? No, it would be a waste of money to gain only 20whp with boost so that you don't blow up your daily driver.

Why would you get an N/A bottom end and not pursue that? If I were you I would rebuild the head with what you will spend on turbo. Get a PnP, high compression valves, springs, retainers, lmas, valve guides, nice stage 2 cams w/ adjustable gears, valve job, you know make a bullet-proof head to couple to your bullet-proof bottom end you already have. As long as you tune it well you will have a reliable daily driver that you wont have to worry about blowing up on you.

Other things to consider depending on budget: higher-flowing injectors, high-flow gas pump, cometic headgasket, throttlebody, intake manifold portmatched to throttlebody w/ hondata gasket.

I assume you're good on I/H/E since you have AEM EMS2 (gotta have some stuff to tune if you spend that much on tuning)

I apologize if it's not what you wanted to hear, but if you aren't changing pistons it would be a terrible idea to boost your engine as-is. If only you had at most 10:1 CR it might be manageable with some really good tuning and low boost, but with 11:1 I would not consider boost as an option.

lilbill97 · 11-15-2010, 08:22 PM

sell the pistons and get 9:1

lilbill97 · 11-15-2010, 08:23 PM

or buy my car.lol

sol95 · 11-16-2010, 05:15 PM

gonna get CP pistons.

8.5 or 9.0 cr?

I think 8.5 ain;t gonna have no balls down low.

9.0 it is then

lilbill97 · 11-16-2010, 07:04 PM

i have 9:1 in my car, from 3-8k rpms my cheeks flap.lol

goldluderay · 11-17-2010, 07:51 AM

get a thicker head gasket...that will lower the cr some
also 11.0.1 and low boost is still decently safe on 8-10psi
it will have too be ran on atleat 93octane or better

but high cr and boosted set-up make great power

how do think pro drag hondas make over 1000whp
there running over 11.0.1 cr and 40psi of boost

mortifiedvictim · 11-17-2010, 07:30 PM

I was waiting for someone to say something about a thicker head gasket... It's not going to lower the compression nearly enough to make it manageable for a daily driver. This isn't a track car that he won't mind blowing in 10k miles, OP should go with lower compression pistons and take the "safe" route if he needs the engine to last. It takes a lot of luck and some god damn amazing tuning to get a reasonable amount of miles on a FI + high compression motor.

goldluderay · 11-18-2010, 01:09 PM

he could also have the piston dome's flat cut
allmost any machine shop can do this.....it will lower the cr

mortifiedvictim · 11-18-2010, 07:05 PM

I didn't think about him modifying the piston's he has. I don't know enough about pistons to say how much of a difference it will make as far as CR goes or if its worth it $ wise.

But since he said he's getting CP 9:1 all of this is inconsequential.

goldluderay · 11-19-2010, 06:36 AM

yeah that is true
but i have seen people drop a full point by having the piston dome cut
if he cut the domes and got a thinner head gasket he could get really close to
9.5.1....but w the machine work spent on all of that too do it properlly
he could just about buy a new set of pistons....