Why not boost the ETA?

[napabavarian]

John-

I forgot to ask what year your firebird is, I have an '87 Trans Am GTA in the barn waiting for a brightening :D

[napabavarian]

I'll elaborate; Think of it like this, with N/A engine you are sucking air in, so the restriction is a real problem, and polishing the intake will help smooth things out, with forced induction you are pushing it in, kind of like sucking on a straw VS sucking on the open end of an air compressor hose, so the difference is less as a percentage of total flow, and you can always turn the boost up a little :p.

If you want insaine horsepower power you would be best off with an i head, but the e head might actually make a better DD because of the low end torque, you could get the turbo to spool up sooner, smaller turbo that comes in sooner.

The real question is what are you going to do with the car?

Yes, I understand the flow difference between the i and e heads.

BUT the same goes for my other car (as explained above), yet the iron heads with boost will still do quite well (~12-13sec 1/4's).

When you have a lesser flowing head and you apply boost, you have lesser issues with port volume, velocity, and definatly making power, than you would talking N/A.

Does anybody here (or can link me to threads with) flow data on the various stock heads? Perhaps someone maybe even went as far as testing with/without manifolds as well?

EDIT: I posted before you pic insert of the dyno graph ;)

Anybody have numbers on the e head and boost?

[moatilliatta]

put a 323 head on it. I has one.

[ForcedFirebird]

I have never heard anybody argue against the ETA because the CR is too high. People argue against turboing an eta because of the shitty head (which you already knew). Only uninformed people would argue that 9:1 CR is too high for boosting.

Ah, OK.

I went through and read a bunch of boost related threads, and it seemed the compression was mentioned often.

[Jordan325iC]

I have never heard anybody argue against the ETA because the CR is too high. People argue against turboing an eta because of the shitty head (which you already knew). Only uninformed people would argue that 9:1 CR is too high for boosting.

[ethree]

Only if you over-rev ;)

Or have a spike in boost ;)

[ForcedFirebird]

Don't weak single valve springs like those found in the eta head like to allow valves to float and fuck shit up?

Only if you over-rev ;)

[ethree]

Don't weak single valve springs like those found in the eta head like to allow valves to float and fuck shit up?

[ForcedFirebird]

The compression is not the problem its the shit head on it..

Yes, I understand the flow difference between the i and e heads.

BUT the same goes for my other car (as explained above), yet the iron heads with boost will still do quite well (~12-13sec 1/4's).

When you have a lesser flowing head and you apply boost, you have lesser issues with port volume, velocity, and definatly making power, than you would talking N/A.

Does anybody here (or can link me to threads with) flow data on the various stock heads? Perhaps someone maybe even went as far as testing with/without manifolds as well?

EDIT: I posted before you pic insert of the dyno graph ;)

Anybody have numbers on the e head and boost?

[backtrail69]

Yes, I know about the i heads ;)

I'm doing the same thing on my v6 motor. Using a '94 block and '04 heads in the Bird. The old iron heads flow ~127cfm intake and the aluminum '04 heads are ~225cfm.

My question still remains:

Why is the compression on an eta too much?

The compression is not the problem its the shit head on it..

Here is my 2.8 (2.7 crank 1mm overbore and i head (stock with 273 cam)) at only 10 psi... I suggest you invest in i head swap

[ForcedFirebird]

Do it to it it'll be a torque monster if it is done right.

Oh, I have a few plans for the eta :D

I'm swapping in a GM ECM (same ECM that controls a Syclone/Typhoon ;)), then an i head swap, then undecided if I want to see big N/A numbers, or boost it.

[ForcedFirebird]

Just boost it and if you dont like it throw an i head on it ,but you could just go ahead and put on the i head.(FLOWS BETTER)

Yes, I know about the i heads ;)

I'm doing the same thing on my v6 motor. Using a '94 block and '04 heads in the Bird. The old iron heads flow ~127cfm intake and the aluminum '04 heads are ~225cfm.

My question still remains:

Why is the compression on an eta too much?

[napabavarian]

Do it to it it'll be a torque monster if it is done right.

[ban1]

Just boost it and if you dont like it throw an i head on it ,but you could just go ahead and put on the i head.(FLOWS BETTER)

[ForcedFirebird]

No... The reason its stupid to boost a eta engine is revs... HP is calculated (TQ x RPM)/5252 and if you arent spinning very many RPMs you aren't going to be making much power... also the head doesnt flow very well compared to an i...

Then how do you explain the turbo diesels that won't turn as many RPM's as the 2.7 even?

What I want to know, is why is 9:1 compression too high?

Here's a vid for 'yas. This is a 9.1:1 at 15psi (the car I built for a customer last Dec)...

http://videos.streetfire.net/video/Corsica-goes-129-106_193741.htm

http://videos.streetfire.net/video/More-track-fun_166595.htm

A friend came down from central Florida and I made the kit from scratch for him in about 48hrs, the only thing that was made before hand was the headers up to the collectors (I made them on an engine stand). In that 48 hrs, found time to do the side exit exhaust, and make the small items on my CNC machines, like flanges etc.