RX7withNitrous

So on my T04E 60 trim My "sweet spot" would be 2 bar right? How much boost is that in psi?

pillage6

Somewhere around 29lbs., damn that's alot of boost.

I think I read somewhere that 1bar= 14.7 psi.

rotaryengineering

Here is my recommendation on jetting your setup. Remember this is only my recommendation from my experience. You do not need to take my advice I am just going to put it out there for you to consider.
I would use the following in your scenario:
Weber 40 IDF
160 Air Corrector Jet
F-3 Emulsion Tube
215-230 Main Fuel Jet
32mm Choke

This recipe should make roughly 400 RWHP with your turbo set to 12-14psi.

I have a part you might be interested in it is a rare 40 IDF top that has a Fuel Enrichment circuit built into the carb top. No gimmicks or BS I run these really old 40 IDF Weber tops on my own car. If your interested I can provide a picture to compare against what you have on your car.

Albert Mets

pillage6

The picture would be cool.

I have not figured out how to remove/ install new venturis, otherwise I might try what you are talking about since I have a spare carb at home.

I also have a gross? jet that meters fuel and is connected to the float, do you know what I am talking about?

pillage6

Hey Albert, you have my other email address right?

If not, here it is: neil@predatorcues.com

Marshall

Though your conversion makes it work, the y-axis is thr pressure ratio through the compressor. Pout/Pin, so 2.00 is around 1 atm of pressure (14.7 psi of boost). 2.00 is NOT ~30 psi.

pillage6

Man, I think my engine would fly apart at 20 something lbs. of boost.

Marshall

No no no! You can't talk terms of efficiency by pressure alone -you have to know how much air is going through your engine. "How much psi is the sweet spot?" questions cannot be answered without knowing more.

To answer your question, if your engine flowed 26-32 lb/min of air at WOT at the hp peak, your sweet spot would be ~1 atm (14.7 psi).

pillage6

How do you measure how much air your engine is taking in?

Marshall

There's the rub. Since we don't have mass air meters, you would have to determine it some other way. I'm guessing here now but, if you know the BSFC and the hp, I think you can back out airflow. Same with air/fuel ratios -you can log the amount of fuel going in, look at the AFR, and back out an approximate air flow number. Anyone know for sure?

pillage6

What's a BSFC?

Marshall

Its Brake Specific Fuel Consumption. Hopefully Peter (RICERACING) will chime in -he knows all this stuff, or you could try a search on it.

pillage6

Thank you for the info, I was just too lazy to search.

pillage6

Okay, searched and read, now my head hurts.

eViLRotor

iTrader: (2)

You have a T04E 60-1, not a "60" trim...they are two different compressors.

The 60-1's sweet spot is at 1.7 bar (10 psi).

The "60" trim needs 2.4 bar to make what the 60-1 makes at 1.7

pillage6

1.7 bar= 10psi?

eViLRotor

iTrader: (2)

psi + 14.7 / 14.7 = bar.

10 psi = 1.68 bar = 1.7 rounded up.

I read somewhere, that you are actually supposed to divide by 14.2 for some reason, but nobody does.

pillage6

Wow, that's a new one.

Thanks for the info.

RX7withNitrous

ok so should i be running 29psi or 10psi?

eViLRotor

iTrader: (2)

Well, you should be running the amount of boost required for the hp you want.

For the T04E 60-1, the sweetspot is 10psi. That should give you anywhere from 300-400 bhp depending on certain factors.

Nobody running 29 psi on a 60-1, lol. That puts you off the charts...

...no to mention that you'd need race gas and a standalone EMS.

Marshall

Whoa, hold on now, you're going to confuse people going from guage to absolute pressure. 1.68 bar is around 10 psi if you're talking absolute pressure, but most people in the automotive world use guage pressure. This means that 0 on the boost guage is atmospheric pressure and not outer space pressure. 1.68 bar on a boost gauge and you'll be at 25 psi.

RX7withNitrous

ohhhhhhh ok so 25psi on a boost gauge that's what i needed to know

Marshall

No, he's was looking at the pressure ratio of 1.68 for your turbo. P2c/P1c = 1.68 this is ~1.68 x ambient pressure = 24 psi. Now you have to subract the ambient to get the guage so: 24-14 = 10 psi on your boost guage -assuming your engine takes in the corresponding amount of air of the compressor map.

eViLRotor

iTrader: (2)

Yeah, thanks for clearing up the confusion. I was just relating my info to compressor maps

RX7withNitrous

so confusing