What compression ratio to run on a boosted B16a?

[paagle]

I am currently boosting my B16a with a T3/T04 turbo . All internals have been upgraded already as some of you may know already with some of my previous posts. The engine is currenly being built but I need some advice on what kind of compression ratio I should be looking to lower mine to. The pistons I have, are rated at 8.5:1 (0.5mm oversized) and currently I have been told the engine may end up running at 8.0:1 to allow for more boost.

I have been told in the past on here that this may be too low as I may end up losing too much power low end.

What would you guys reccommend as the ideal compression ratio to run, to keep some of the low end power but then still be able to boost pretty high

I know I wont be able to boost too much as traction then starts becoming a problem and the T3/T04 is rated as max 550hp. This will be my daily driver so I need figures that will work for me.

Please help!!

 

[SeanMc300]

9.0:1 is a conservative ratio.. 10.0:1 is fine, but youll need some good tuning.

 

[BIG-FISH]

9.0:1 is a conservative ratio.. 10.0:1 is fine, but youll need some good tuning.

yea i would stay in this range...but tuning is going to be the biggest aspect

 

[paagle]

wow....10 to 1....that seems awfully high guys...especially as the B16A2 as i have is 10.4 to 1 stock. Are you sure I should be looking for figures that high? 9 sounds good but 10 maybe too high...i may be wrong hence having to ask the question but surely for turbo purposed, only decreasing the compression by 0.4 surely cant be enough to stop detonation?

 

[evan2]

9.5:1 too low and its just no fun
it depends is she a track whore or mostly street
i mean yea its nice to say i boost a lot and u will make power

though ive been in a car with near 8:1 and it wasnt to bad down low

 

[paagle]

it will be mainly street ...like i say i want to use this as my daily driver but still have the option of taking it on the track...if i did go up to 10 with compression, what would be the maximum boost i could run without detonating?

 

[SeanMc300]

what size turbo???

 

[paagle]

what size turbo???

Dude....i put that in my first post! Its a T3/T04 Turbonetics turbo. I can't remember what the figures are for it but its rated at maximum 550hp.

 

[Mr. Lin]

If it's rated at a maximum of 550, you're prolly gonna get a max of 400hp on it with the typical budget.

 

[SeanMc300]

dood, like my balls, i was asking because there are about 40 different variations of the t3/t4 turbo. the "figures" are the only important thing..... so you bought a turbo and you dont even know what size it is...awesome.

 

[paagle]

dood, like my balls, i was asking because there are about 40 different variations of the t3/t4 turbo. the "figures" are the only important thing..... so you bought a turbo and you dont even know what size it is...awesome.

Sorry dude...what can I say . I don't know the complete ins and outs of turbos and also I didnt have the figures at hand. Right I have the specs now, so here goes:

3" Inlet Diameter, 2" Outlet .50 A/R / .63 Hot Side

Stage III wheel.

Hope that helps.

 

[paagle]

Is there anyone else who has input on this as my engine is nearly ready, but I need to confirm the end compression figures. 10 to 1 seems awfully high but seems to be the current recommendation. Any other input would be greatly appreciated.

 

[Shiznit]

okay i decided to bump this thread rather than create a new one...

im going to be boosting my em1 in the near future. and am looking at getting the same turbo as paagle. my car is daily driven, and i dont plan on mashing my gas every time i stop and i typically shift around 4k. i still want to have a lot of my low end so that i dont have to boost all the time. so as mentioned above, i was thinking about staying in the range of 9.0:1 - 10:1. oh and i plan on building my internals also.

my questions are:

1.) if my b16a2 had a compression ratio of 10:, what would be the maximum boost i could run without detonating and how dangerous is it to boost in general with that compression?

2.) about how much of my low end will i lose if i were to go with 9:1

 

[Tactics]

you can run any Fu(*&in ratio you want.... just make sure the b***h is tuned. Hell, there's a few videos around here where a guy in a Teggy has an 11.5:1 boosting something like 14lbs (i think) He makes over 500whp WITH GOOD TUNING (and race gas of course) Try www.evans-tuning.com. Its under "mikes GSR" or something like that.

 

[stolle]

i would go for 9:1 and since you have internals i would boost to 15psi thats two atmopheres and with twice as much fuel in theory you will make twice as much hp 160x2 or 320hp in theory with losses you will prolly end up with 280-290hp thats more than enough for the street and with 9:1 CR it will be nice and drivable with enough low end torque if your really concerned about low end you should consider a smaller turbo one that spools around 2000-3000rpm like a td05 big ass turbos dont always mean big power especially on a 1.6L....

 

[stolle]

okay i decided to bump this thread rather than create a new one...

im going to be boosting my em1 in the near future. and am looking at getting the same turbo as paagle. my car is daily driven, and i dont plan on mashing my gas every time i stop and i typically shift around 4k. i still want to have a lot of my low end so that i dont have to boost all the time. so as mentioned above, i was thinking about staying in the range of 9.0:1 - 10:1. oh and i plan on building my internals also.

my questions are:

1.) if my b16a2 had a compression ratio of 10:, what would be the maximum boost i could run without detonating and how dangerous is it to boost in general with that compression?

2.) about how much of my low end will i lose if i were to go with 9:1

all these questions about how you want low end torque and everybody wanting to run t3/t4 turbos those turbos are big especially for a 1.6L it wont spool until 3000-4000 rpms and are IMO overkill especially on a street car if you were drag racing (for points) then yeah for street you would have a lot more fun and a lot more low end torque with a smaller turbo ie full t3 or td05...

" if my b16a2 had a compression ratio of 10:, what would be the maximum boost i could run without detonating and how dangerous is it to boost in general with that compression?"

as high as your tuning ability, and only dangarous if you dont know what your doing....

"about how much of my low end will i lose if i were to go with 9:1"

probably none...

 

[Shiznit]

hmm thanks, yeah ive been reading up on costum turbos all night, and i havent gotten any sleep yet. but im lookin into gettin a garret t3 super off of a thunderbird i believe

 

[Ravage70]

super 60 is not found on any production car
its aftermarket

a t-bird/stang/merc has a 60 trim
63/60 for manual
48/60 for autos