McGehee/Forza Supercharger Install!!!

How does the non-O2 (lambda) fuel distributor work with the lambda system you have in the car now? Wouldn't it just make sense to just get rid of the O2 altogether like Branko's car?

 

Ignition timing? A 4v with 10 psi boost will handle 22-24 degrees, I got away with 22 with the roots blower put the inlet air temp to 260+F, so you guys should be good to 24 with the lower air temp.....that was with the A/F at 13:1, any leaner and you'll need to pull the timing back. Going from 16 to 22-24 should be good for 20-30 hp on the dyno.

 

I forgot about the meter you installed in the car. I was wondering how you were making that O2 sensor and lambda free fuel distributor talk to each other.

 

How do you check/set the timing on a 308?

 

You can check it with a timing light and the timing mark on the flywheel, mine has a timing dial so you can read the TDC timing mark at any actual engine timing. The only practical way to change the timing on an "i" car is to replace the ignition system, which Scott, Mike, and I have all done.

 

Boost is your freind

how much of it do you have know BTW?

with the A/F at 11.5, you almost have too much fuel, that should handle the 22-24 timing with no problem.

 

Congrats Mike.

Glad she's running nice and strong.

Supercharger ALL THE WAY!!

 

It's got to be right around 300rwhp now then and just a joy to drive.

You're going to want something like 24-28 degrees of timing then, I'm guessing a flat 26 is what the dyno will say is best.

 

All chant: Show us the dyno!

Congrats!

 

the map i wrote for mike has his peak at about 34* based on 8psi at 6k.

 

no, no, I meant the dyno will like the peak timing at WOT to be about 26.0 (26 flat), the rest of the table should be the rest of the table. Nothing crazy.

 

I think 34 degrees is too much for an NA 4v and way too much at 8 psi. 32 or maybe 33 (I run 32) degrees at 0 psi and drop to about 26 at 8 psi should give the best results. Too much timing is worse than not enough on the dyno....but see what the dyno says, I certainly been wrong before.

 

Mark here's a interesting experiance, I spent 2wks working with an engineer and engine builder for the Ferrari challenge series. he wanted to adjust the timing on my 2v, so ofcourse I let him. he advanced the timing to 18* at idle and it peaked at 44* ! the car ran like a scalded cat! amazing! the downside was that it had to run RICH and subsequntly the mpg went right down to about 7~8. it was a bit to stinky but man did she scream.

here are the numbers from the gas analyzer:
18*~44* timing
HC: 1220 ppm
CO: 0.61%
CO2: 4.09%
O2: 20.8%
RPM: 1025


14*~40* timing
HC: 1158 ppm
CO: 0.57%
CO2: 4.07%
O2: 15.7%
RPM: 1000

HC: 355 ppm
CO: 0.57%
CO2: 5.79%
O2: 23.0%
RPM: 4000

 

the exhaust leak is very obvious from those readings. the others don't jive so well, it suggests a dead hole or incomplete burn. my thoughts are the 30* of overlap don't help. i'll be doing more tweaking on the gas readings with the new cam timing.

 

Racing and street are just never the same. To make the engine snappy, you need to get a lot of timing in fast......but to make it idle smooth and not hunt you need stable and relatively low timing. Clearly a conflict. These days I tend to err on the smooth street side because it makes the car more fun to drive, but 10 years ago I’d sit blipping the throttle to keep the race engine I installed in my streetcar running. It’s all about preference.

On the 44 peak, it will make the engine very snappy in a no load condition, but I find it incomprehensible that it makes hp….that’s nearly Nitro timing. You didn’t try that on the dyno by any chance did you?

As a reference, my 4v engine at 10 psi with a 260F inlet temp made peak hp at 24 degrees. Going to 26 cost about 10 rwhp.

 

Oh no!!!! You're sure it's not just the belt slipping right, that can be quite loud.

If it's the SC, I'd pull it off for the track....it might not seize, it might send bits of metal into the engine instead.......

 

Wow, 44 deg...!
but you need to run 120 Oct. Av Gas,
right...?

 

Oh man, that s**ks.

How many miles did you with it?

And is this the same Vortech SC model that Scott has?

Chris