That's a lot of comp for boost. I hope you have a real good tuner to run either of those compression levels.
Higher compression doesn't restrict boost levels, as a matter of fact its great. You just don't have as big a window for error when tuning.

 

run the 10:1 so that you have a little bigger window for error on the tune.

running that much compression will help throttle response and you can make more power with less boost.

 

you should be fine if you're going to burst it once in a while, but if you heavy foot i wouldn't do it, i would look into getting into a d16 with some low comp pistions n nice rods.


z6 head is probley better off.

 

Stop giving out bad advice.

Find yourself a good tuner and you should have no worries no matter what CR you run.

 

Stock internals? I sure hope you have a good tuner

 

bad advice? apparently you've never laid your foot off the petal like most other morons with high comp.

daily driving with boost = low compression for the win, it will last longer

BUT you may run 10.1 with lower ammount of boost, with a good tune you goon.

 

Daily driving with boost with higher comp FTW. That way your car isn't a pig out of boost. The higher compression makes for a better street car because the car doesn't have to be boosting to move. Try driving an 8:1 motor around without hitting boost and tell me low compression is better for a street car.

Or better yet ... just watch this. That's an 8.8:1 CR motor out of boost. That is why, for a street car, high compression = WIN.

 

 

The issue with every turbo car is the outside temp. So when you tune the car make sure it is hot outside. It will run better when it is cool, and it will survive the summer months.

High Compression equals high octane fuel in your tank. It's detination that kills motors. So you are going to have less room for error. The high compression sounds good until you weigh all your options. I was going to do a similar build, but decided that low compression was easier when you wanted to pull up and pump some 93. If it is strickly a drag car or weekend warrior then I say go for it.

Also you need to be looking at Compressor Maps. 7lbs is not always the same. Most turbos are different, so you will need to study maps like the disciples walked with Jesus. Daily.

http://www.turboneticsinc.com/sites/default/files/HowToChooseATurbo.pdf

http://www.turboneticsinc.com/sites/default/files/Turbo Matrix .pdf

Compressor Maps | www.TurboneticsInc.com - Boosting Since 1978 | turbochargers, intercoolers, wastegates, blow-off valves, controls, boosting systems, turbo kits, forced induction parts & accessories

 

you = BFF >:O

 

Check out the build thread in my signature. You'll see what you can do with a conservative tune on a d15b7/z6 mini-me with boost.

There's a dyno chart on there. 10.2:1 CR on ~7lbs of boost, on a small turbo. Enjoy.

Oh yeah ... and that bottom end has 195k on it.

 

I think you're splitting hairs over .3 of compression but better mpg on the y8. If you run the graphite gasket witch may be ok with you're power goal you'll be 9.95:1. But I think you will be at 10.46:1 z6 head or 10.91:1 y8 head if you enter .028" head gasket for a 3 layer compressed.

 

I think he's assuming for his CR #s that the b7 gasket will be used, which is pretty thick. I am using the z6 gasket which will yield: 10.2:1 CR w/z6 head ... and 10.6:1 w/y8 head.

 

your comparing an evo with a huge ass turbo for what? we drive civics... my turbo gsr out of boost at 8.8:1 comp isnt a pig whatsoever... higher compression is nice.. but imo id rather stay a bit lower and be a bit safer.
if you size your turbo correctly for a street car you dont really NEED a higher compression setup...

heres a vid.. 4th gear pull from 40-130 ish i think... YouTube - jimmyb34's Channel

 

i see your point...how much boost are u running tho? this is a low boost build guys. tryin squeeze power from a small turbo. i have a larger turbo on the side but thats another story.

garret m-24 a/r .80 compressor exhaust a/r .84

compressor fan measures about 1 5/8"
\garret tag says:
made in japan garrett
wi 0534j
14411-50f00
466113-1

i think i found the info i was looking for :
T-25 journal bearing

comp. 54.36mm ex 60tr
turb. 53.00mm ind 62tr

stock from a Nissan SR20

 

planning to do this route too..... for daily driving and to use my car at a road course (small track)

base on Honda D-Series Compression Calculator by ZealAutowerks

i'll have a 10.55:1 comp ratio

everything d16z6 except the rods using the FJ rods and using a T25 turbo

 

As usual, it call comes down tot he tune. With the Y8 setup you will NEED less timing EVERYWHERE to make good power because with the Y8 head's design, the static and dynamic ignition timing does not need to be as advanced to light the mixture due to the Y8 head's swirl inducing head design. A tuner that will work with this combo needs to be aware of that, so that they start out at what most people would consider absolutely stupidly conservative timing numbers.

Either head will work pretty darn well, and those static compression numbers are nothing to be concerned about, as they are lower than what many people in the B-series world deal with and have great success with.

Just don't be stupid and run crap gas. LOL!

 

thanks everyone, tahts what u was thinking stock b series motors run higher comp then 10.5 and plenty of people turbo those well over 7 lbs. after all this especially that extra tunning issue im gunna run the z6, just disappointed i did alot of labor on the y8. guess i just gotta ebay it

 

a buddy of mine is running 10.5:1 with a 60-1 @ 12 psi with no problems and hes had his setup for over a year... it just goes to show that its all in the tune

 

sigh, research must be terrible

on an otherwise stock d15b7, I plan on running 10.8 compression with a k03 or k04 turbo for my gasmileage build

plenty reliable if your tuner is competent

 

sigh, research must be terrible

on an otherwise stock d15b7, I plan on running 10.8 compression with a k03 or k04 turbo for my gasmileage build

plenty reliable if your tuner is competent

This will work with an .043" head mill and enter .028" for the 3 layer head gasket thickness.

 

vtec is an annoyance

it adds rotating weight, it adds tuning time, it adds wiring, etc

plus the overall outcome is the same, so why bother with extra stuff that can go wrong?

NONVTEC FOR LIFE!!!!!! :3dbiggrin:

 

outcome is the same? howso? vtec seems to add quite alot of power

 

alright, take your average d16a6 and d16z6

modify both for an all motor build

they will be close enough that vtec wont mean shit

stock for stock, of course vtec motors win over non vtec

honda established a big thing with vtec, they tend to enforce that when possible

 

so how do u explain bisi moto 700 hp z6 build? havent heard of anything close to that non vtec. in fact pretty much all the builds i have seen here either use z6 or y8 head

 

Vtec just allows you to run a larger cam while still being able to idle well and have some power/torque in the lower rpms.

 

i ran a 1.5l vtec-e 10.6:1 on 10psi. It was a wrx turbo. It was a fun car. Let me help you by attempting to illustrate a few points I learned.

1. Margin for error: been discussed, won't beat a dead horse...

2. Example: A honda 1600cc engine has about 400cc per cyl. A higher static compression ratio means that 400cc is being squished into a smaller area. For a 10:1 engine it would be compressing 400cc into about 40cc at tdc. I'm sure there's a way to calculate approximate cyl pressures, but I don't know how. For a 9:1 engine, you'll be compressing 400cc into about 44.44cc. Now the fun part... You can alter cyl pressures with the turbo! The same pressure in a larger space will potentially make more power! You get an extra 4.5cc per cylinder to cram pressure into by going with 9:1cr. Plus a properly sized turbo for low boost will hardly know the difference between static CR at this power level.

There are many factors to consider, but that one thing I learned from the higher comp turbo experiment showed me 9:1 is widely used for a reason. Some people, me included, just have to learn the hard way...

 

Click me for 12:1 and highboost

Click me for 11.8:1 and highboost

If you have a tuner with a clue you will be fine with the higher comp makes more power more torque and will improve throttle response there is no evidence that it helps spool times though. Ask JFK what comp his new sleeved motor is going to be? People have just stuck with low comp because thats what they had to use back then due to lack luster tuning methods with the advances we have today high comp and boost should be no problem what so ever.
/thread

 

Both a non-VTEC and a VTEC engine can theoretically produce the same power, but the VTEC engine will make more average power since it can make a broader powerband. It comes down to application and I guess preference.

 

I have to agree with DDD tuning a non vtec car is super easy didnt take me anytime to tune my crx first time ever tuning it ran great as well