DeltaT

iTrader: (5)

I don't feel like I'm getting the boost I expected.

The setup is:

383
Holley 950 Pro w/FJO wideband
Edelbrock E-Tec 200 heads, ported
Solid roller, 230/236 at .050, 112lsa, .589/.602 gross lift
50lb. injectors
Longtube 1 3/4" headers
Big Bell intercooler
Mondo Bypass
7" crank pulley
3.12" blower pulley

I am seeing rubber dust around the blower and mount.

I have only seen boost at the motor of about 4psi.

The belt is pretty tight, and I have excellent pulley wrap. Do I need to make it tighter, or try something else? I am going to check the Mondo operation tonight.

Thanks,

Jim

Pro Stock John

iTrader: (34)

Can you twist the blower belt 90 degrees? If you can it's too loose.

DeltaT

iTrader: (5)

Yes, I can twist it 90 degrees. Will I start damaging anything if I get it tighter? I have excellent wrap on the blower pulley, like around 290-300 degrees.

Thanks,

Jim

SOM_of_a_Beach

just dont be like me and brake your tensioner bolt

EPP

iTrader: (22)

You need to tighten the blower belt much tighter than what you think is necessary, basically you want it almost tight enough that you could strum it like a guitar string. I've never had any problem related from having the belt this tight. You should never see blower dust on the housing. Bob

ls1290

iTrader: (20)

How much force or pressure are you talking about to do this?

Keith

Pro Stock John

iTrader: (34)

With your fingers...

DeltaT

iTrader: (5)

Thanks all, I will try tightening it today.

Jim

Pro Stock John

iTrader: (34)

If you can flex the belt, like you can your stock serpentine belt, you can get slippage, or worse, have belts walk off.

What blower do you have?

Based on your pulley combo, are you shooting for over 10psi?

ls1290

iTrader: (20)

What about C5s where the serpentine and blower belts are one in the same?

Keith

DeltaT

iTrader: (5)

I am running the Vortech V-2 S-trim. I just put a .5" shorter belt on it and cranked the tension up so the belt was much tighter than I've tried in the past.

WOOHOO! Got Boost! 7.5lbs of boost! THANKS! This is about what I expected after the intercooler. I could really feel the difference, and the datalog showed everything where it should be. No knock, AFR at 11.6, IAT at 124, timing at 22degrees. Hit the rev limiter for the first time.

I did have some 100 in the tank - I am hoping to be able to support 8lbs. intercooled on pump gas (91 here in NorCal).

I still need to play with the upper rpm fuel map. I see in the log where the duty cycle hit 98% very briefly. I hope that I can trim fuel to the point where it doesn't exceed 90%.

Does everything sound reasonable? This is my first FI tune and I'm trying to be very conservative.

Today's Picture:



Thanks again,

Jim

Pro Stock John

iTrader: (34)

Nice setup! I guess you can see how the 3.12 works out, and then go to the 2.95.

Figure that the belt not only has to be tight, but it's stretching somewhat too. I'm running 2.85/8.00 pulley combo and have seen 18 to 21.5 psi, though my combo has not seen 21psi down the track.

DeltaT

iTrader: (5)

Thanks, John.

I can't really go any faster because of the absolute redline of the V-2 (50,000).

This pulley setup hits the redline at 6200rpm.

Is it really bad to exceed the stated blower redline even by a few hundred rpm? My 2.95" pulley would put me to about 53,109rpm at 6200 motor speed. I am running a -8 drain line plus a -8 blower vent line w/K&N (as suggested by Vortech in their Racing User's Guide).

Thanks again,

Jim

gator's 99TA

iTrader: (2)

1) you can go past what vortech recomends. i would feel safe turning it to 55-56K rpms

2) figure a rough estimate loss of 10% belt slipage (even if you think you arent slipping).

DeltaT

iTrader: (5)

Cool, I'll try the 2.95 pulley next time I pick up some 100.

Thanks,

Jim