Balance CR & boost....experience with limits?
 

Ok...so I'm venturing into uncharted territory by turbocharging my built D16A1.

After going round & round on this engine build with taking measurements, asking questions, getting wrong answers, hauling parts to the machine shop multiple times, this motor is going to be installed as is.

Originally it was to be 11.8:1 NA. The motor is built with Endyn Rollerwaves & Eagle H-beam rods, ARP head studs, etc...basically everything except posting the block, DOH!

Anyway, it'll be installed back into my '86 CRX Si any week now as I am sick of looking at this thing on the stand. As it sits now, with the latest round of meticulous measuring done myself (if you want something done right...), the motor is 10.68:1.

For those who don't know me from every other Honda message board, I've been around a while. My CRX already has an '89 D16A1 in it, so the wiring to run electronic advance, & subsequently a Zdyne gold ECU is all there.

I'll eventually get to my question, but I'd like to first make everything crystal clear so there aren't a bunch of OT replies about how I need this & that engine management. I know all that already, as I've been way around the boost block with my supercharged '91 Civic Si.

Since this motor as it sits is not at the streetable limit for NA (my original intent to run it at 11.8:1), I am seriously considering going turbo. However, I realize that it's probably at the upper streetable limit being 10.68:1 as it sits.

Ok, now for the question. What experience (if any) does anyone have with running a fairly high static CR & turbo? What realistic PSI could I put to it without grenading? Am I dreaming by considering putting a turbo on this thing? I figured, from all the rumor floating in the net that 6psi shouldn't be a problem, and 10 being the upper limit.

Any helpful replies are appreciated. Flame on...
-TJ

Oh, I should add that the immediate plan is to install & break the motor in NA, then scrape together a turbo system.

Re:Balance CR & boost....experience with limits?
 

uhmmm with Zdyne...I would go to 12-13 psi as you have a built engine except for the sleeves..I would worry more about what the sleeve can handle(boost). I wouldn't boost more then 15 psi....If you tuned it right. but you could go higher as BoostedED9 showed us it can be done on stock sleeves. His rod's snapped, but yours are stronger

Re:Balance CR & boost....experience with limits?
 

Ok, so 10psi with 10.7:1 CR shouldn't be a problem.

Thanks! Anyone else?

Re:Balance CR & boost....experience with limits?
 

u might wanna start at 5psi and see what it does..

thats a high CR and yes it can be done fine.

Re:Balance CR & boost....experience with limits?
 

you might have to put octane booster in it... like 104 or whatever its called. but you should jsut try it with premium until it detonates. your motor won't blow detonating a couple times. even a bunch of times. but after a while ---- gets weak and breaks

Re:Balance CR & boost....experience with limits?
 

If you got your fuel tuned real good and just use good gas not shitty gas at least octane 93 it can go without detonating.

Re:Balance CR & boost....experience with limits?
 

start low boost and work your way up

Re:Balance CR & boost....experience with limits?
 

TUNE YOUR FUEL!


hahah semmy ;D

Re:Balance CR & boost....experience with limits?
 

start revising the spark table pull alot of timming. you wont be able to run alot of spark advance with that CR with alot of advance with convetional intercooling. now you could use water injection its been shown to work quite well wth a fiarly minimal loss in power due to water vapor displacing air volume.

thats my 2cents

Re:Balance CR & boost....experience with limits?
 

Well when you think logically about it, it's not initial compression which kills the motor (static compression) but instead it is dynamic compression which will cause detonation without a good tune.

If a motor is running 8:1 compression and boosting 20psi, and another motor is running 11:1 compression and running 10 psi, if both motors are making, lets say, 350hp, then their dynamic compression is the same at that point.

Bottom line is, starting out with low compression is working against your goal, which is horsepower, and with a good tune, you obviously will be able to make this work. As far as how much boost, like someone said before, I'd start out under 10, maybe around 5-6, and work your way up from there. Be conservative with your timing at first, and keep the afr's down around 12ish; maybe a little richer even. I think you'll be alright and I think you'll have a hell of alotta fun. Good luck! :)