[gibbons]

My new set up (468, 9.5:1, 248/238, Rhoads, RPM performer, Mighty Demon, Hooker Comps, Digital 6) will rip your head off when I stomp it in the power band, but it seems to sputter at 5500+. And it deceleration surges below 2000. My Edelbrock AF monitor with 7 LEDs from 11.5 to 15 always shows about 12:1. But I guess it's a narrow band and sux?

Sooo..... should I spend $300 on an Innovate wideband, or $300 on a chassis dyno with 5 gas analyzer where the guy says he will jet and time it to perfection? I have only talked to him on the phone, he says his dyno is good for 250 to the rear wheels. I am guessing that the TKO and 12 bolt 3.73 aren't going to drag it down that far, so will I miss out on peak tuning anyway?

 

[J70Chev]

Where 'out west' are you? I got 600 bucks worth of dyno certs for a shop in So Cal if you're interested, 300 for both, or 150 each

 

[gibbons]

Not far enough west, the round trip would $1000 of gas away :sad: Thanks for the offer!

 

[Camaro_fever68]

Depends on what you want. The chassis dyno operator will probably only jet for WOT. With the wideband, you can do that yourself and if you want to, you could set the carb up for gas milage and WOT performance. A chassis dyno, IMO, is a waste of time and money. A wideband and a highway and drag strip is the way to go.

 

[dadeo-3]

I know you may laugh, but don't flame me too badly.
I put in an exhaust gas temperature guage in recently. I have tuned my motor using it. I could not be happier with the results. My WOT was right on, but my cruise/transition circuit was way rich. After tuning with the EGT, my cruise mileage doubled and my plugs look much better.
Smitty

 

[eric13617]

My new set up (468, 9.5:1, 248/238, Rhoads, RPM performer, Mighty Demon, Hooker Comps, Digital 6) will rip your head off when I stomp it in the power band, but it seems to sputter at 5500+. And it deceleration surges below 2000. My Edelbrock AF monitor with 7 LEDs from 11.5 to 15 always shows about 12:1. But I guess it's a narrow band and sux?

Sooo..... should I spend $300 on an Innovate wideband, or $300 on a chassis dyno with 5 gas analyzer where the guy says he will jet and time it to perfection? I have only talked to him on the phone, he says his dyno is good for 250 to the rear wheels. I am guessing that the TKO and 12 bolt 3.73 aren't going to drag it down that far, so will I miss out on peak tuning anyway?

Are your duration numbers backwards 248 int./238 exh. or are you running a Turbo grind?If it's the latter then a 250 Hp.R.W.dyno won't help you at all,cause the cam is all wrong.That is unless you have a turbo.And you will probably break the dyno anyway.

Not trying to put you down,but,I'd hate to know I couldn't build a 468 that wouldn't make more than 300hp.at the flywheel or 250 hp.at the wheels.If all you did was overbore the 454 engine and put the fact.stuff back in it;it would make over 300hp.Do you realize that a 468 that only makes 300 hp at the flywheel,is making just 64hp. per c.i.!I don't know if you could intentionally do that,unless you are using the totally wrong components.

The surge below 2000 rpms could be because of a lean idle circuit.And the sputter at 5 grand could mean a lean condition too,or a weak fuel pump,or a bad plug,plug wire,cracked dist.cap,or too much timing,etc.

I don't think I would spend a penny until I figured out what was wrong with my car.:thumbsup:
Just my opinion,Eric.

 

[BACK FROM THE DEAD]

I say O2 sensor.

I also agree that you will kill a 250 HP dyno.

 

[Dave]

I'd buy the sensor. Then You can tune all You want. I would really like to get one for My car.

 

[Sandy]

For some people the chassis dyno route is a good way to go. If you have an experienced knowledgeable operator you may even learn a few tricks.

I have an Innovate LM1 with the rpm module and it works just excellent. Put it on record and do the burnout and run, go back and dump to the laptop and see what changes to make if any.

Last year was running premium gas and pretty rich. First race out this year switched to a 92 octane gas with 10% ethanol. Still just a bit rich but way better with the new fuel blend. This is an example of how useful the wideband is in terms of knowing what is going on and the type of changes to make.

And the car went from a best of 10.82 last year to 10.76 with no other changes.