30thta436

iTrader: (10)

If I'm making 600RWHP with the Vortech G trim maxed out at 800cfm. What RWHP would the T-trim make maxed out at 1200 cfm?

cablebandit

iTrader: (37)

btw: what pulley combo are you using...any slipping?

Pro Stock John

iTrader: (34)

T trim = good up to 825 hp (crank)

Crunch

minus 15% drivetrain loss = 701.25RWHP.
Not bad for the street, IF you can get it to hook up.

30thta436

iTrader: (10)

Thanks for the responses. I was hoping to make mid 700's.

Cablebandit: I'm using the 2.75" pulley. I have never had any belt slipping problems. AT first I had the crank pulley spinning on the nose of the crank. But I had the crank keyed and have had no problems since.

30thta436

iTrader: (10)

Prostock john. I assume you got that number from Vortech's web site. It does say 825 hp for the t-trim. But if you look at the v-9 G-trim it says 575HP, Which is identical to what we put down with the g-tirm maxed out. 576RWHP.
Any thoughts on that?

S_J_H

30thta436,
figure 1.4 cfm per hp at the CRANK for a rough estimate.
So 800cfm =571hp FLYWHEEL. 1200cfm=850hp FLYWHEEL.
You can use .069*Maf lbs/min for a ballpark cfm estimate also.

Vortechs numbers are conservative.
I am seeing over 67lbs/min which is at least 970cfm from my G-trim combo and somwhere around 690 crank hp.
Figure blower and drivetrain losses around 18% and that's about 575RWHP.
I would imagine if you over spun the t-trim it would exceed Vortechs posted flow number as well.
FYI, I am using a 2.5" blower pulley now.Big increase in midrange boost.
Steve

Pro Stock John

iTrader: (34)

Vortech's numbers might be conservative for the G-trim, they admit that.

S_J_H

I have always thought that to be the case.It just really needs to spin some high rpms to flow.
Have you actually had a conversation with somebody from Vortech about the G-trim?

Crunch

I have. From what I gathered from our conversation was that they base their numbers closer to the Efficient Maximum Impeller Speed (60,000RPMs), not the Absolute Maximum Impeller Speed (65,000RPMs). There is still horsepower you can gain by spinning the impeller past the efficient and even past the absolute. But in theory, spinning past the absolute max will not add any more horsepower because the impeller has reached the sonic tip speed (the speed of sound), beyond which you cannot make more power by spinning air. And since independent projects (like 30th's car and others) have shown that there is more power still being made after the so called 'absolute max', this proves that their numbers are indeed conservative. The tech I talked to said they do not recommend spinning past the efficient max (60,000), which is the same reason why changing to a smaller blower pulley voids the Vortech parts warranty. In my car, with the 2.75" pulley, it takes exactly 6476.5 engine RPMs to equal 65,000 impeller RPMs. So we set the redline to 6500 to be safe. Another 24 RPMs is insignificant. And I'm not one to test overspinning the impeller another thousand RPMs.

Pro Stock John

iTrader: (34)

Yeah I talk to their head of B2B and the G-trim is rated for 575-600 hp.

S_J_H

I have taken my G-trim to 69,500rpm now.Risky? I am sure it is.
I have ported the blower outlet and inlet some also.
I am using a Mondo bypass AND a secondary throttle blade before the blower inlet.This is to elimininate as much load as possible from the blower when the throttle is shut.
It's evident the blower is maxed.I won't rev it any higher than this though.
The difference from a 2.85 to a 2.5 pulley was quite substantial.The 2.85 was operating the blower to around it's so called efficiency peak.
I plan on turning over 130mph with a stock 98 cam next year and the G-trim.
Steve