Timing question...

[Scrambler1]

Out of curiosity, how much timing will a built Viper engine take on pump gas? On race gas? Obviously with enough fuel. My engine is 8.89:1 compression and has a Paxton. Anyone know?

Joe

 

[rottenronnie]

Out of curiosity, how much timing will a built Viper engine take on pump gas? On race gas? Obviously with enough fuel. My engine is 8.89:1 compression and has a Paxton. Anyone know?

Joe

Lots of variables here (maybe too many for a good answer to your question): Vehicle Weight, Transmission (Manual or Auto with or without a converter), Camshaft and where it's installed (advanced or retarded), Altitude, Boost level(s), F/A ratios, Race Gas octane, Air Intake Temperature, Pump gas octane, Rear Gearing, o.e.m. heads or heads with fast burn chambers (aftermarket)?, coated valves and/or pistons tops, piston top design, general engine condition (oil vapor is VERY low "octane" and will promote detonation), reverse flow cooling used?, etc; etc.

Do some pulls so you can listen for ping after you get it setup the way you are going to run it; that is a great place to begin.

I run my QC at 32 in the higher gears on 94 at a 3500+ altitude, (10.5:1) which is just on the threshold of ping in my case, if that helps... That is kind of a tuning standard on many engines; but listen for ping and that will help tell you what's up.

Your results may vary

CAUTION: MAKE SURE SOMEBODY THAT KNOWS WHAT TO LISTEN FOR AND CAN ACTUALLY HEAR THE ENGINE PING DURING YOUR PULLS IS STANDING THERE. SOME GUYS (LIKE ME) CAN'T HEAR IT ANYMORE; AND MORE THAN A FEW DYNO OPERATORS I KNOW THAT STILL THINK THEY CAN...



Ron

 

[Scrambler1]

Thanks, yeah I'm letting the tuner handle it all, I'm just trying to be better educated.

A little more info... cam is a little more aggressive than the comp cam, full head work on stock heads, CP pistons, titanium vavle seats, QC with built tranny and converter, 488 rear end, custom intercooler, and more boost than a standard Paxton.

Joe

 

[rottenronnie]

Thanks, yeah I'm letting the tuner handle it all, I'm just trying to be better educated.

A little more info... cam is a little more aggressive than the comp cam, full head work on stock heads, CP pistons, titanium vavle seats, QC with built tranny and converter, 488 rear end, custom intercooler, and more boost than a standard Paxton.

Joe

Joe,

We're all trying to become better educated with these trucks and engines in general..

Sounds like it should go like hell !

"Tips"- Have your tuner wring out the 3-4 shift so it doesn't shift out so early. Mine shifts at 6K and it makes a very "nice" difference; it can also help it stay out of detonation when it makes the shift while pushing that much air (with a N.A. or a boosted truck like yours); and in your case, it will help the engine stay up on the cam and not drop back in r.p.m. to the "lazier", power area; although I don't know your cam specs. This is maybe not a huge deal with your 4.88s, but seemingly small things start to add up. Detonation prevention is what I'm trying to get at here.

I know you are likely 1/4 milin' with your setup, but that shift change alone makes it WAY more fun for "Off Road Use"

With your 4.88s, even with a taller 17" M&H Drag Radial (for example), your overall ratio will be in the 5s or close to it.
So hang On...:burnout: and have fun!

And if you have your injectors flowed, stick the richest one in the DREADED #3 hole in case it is a lean-out issue with these engines; even if you're using forged pistons, 'cause detonation can kill those too.

P.S. How big a converter?

Ron

 

[Scrambler1]

These engines have turned out to be finicky, I already had one learning experience when the stock motor blew. Street tune is going to be fairly conservative, track tune will be more aggressive but still not close to the edge, and still rich.

I'll be running 31" slicks on 15" Bogarts. Nitrous set to spray from 2nd gear on, I'm tuning with a SCT and I'm going to set the shift points for the tranny that way. A problem I had with just the supercharger (650hp) was 1st gear would go by so fast that it would hit the rev limiter before the trans had a chance to shift so I'm going to lower the target shift point in 1st gear to prob 5500 rpm and 2nd around 5700. I may have to go lower but that will be trial and error.

Converter is 2500 stall, if I lose another Suncoast (I'm on the second one) I'm going to change to a TH400 and gear vendors. Hopefully engine break in and tuning will be finished in a couple weeks and I'll have some numbers to post.

Joe

 

[rottenronnie]

These engines have turned out to be finicky, I already had one learning experience when the stock motor blew. Street tune is going to be fairly conservative, track tune will be more aggressive but still not close to the edge, and still rich.

I'll be running 31" slicks on 15" Bogarts. Nitrous set to spray from 2nd gear on, I'm tuning with a SCT and I'm going to set the shift points for the tranny that way. A problem I had with just the supercharger (650hp) was 1st gear would go by so fast that it would hit the rev limiter before the trans had a chance to shift so I'm going to lower the target shift point in 1st gear to prob 5500 rpm and 2nd around 5700. I may have to go lower but that will be trial and error.

Converter is 2500 stall, if I lose another Suncoast (I'm on the second one) I'm going to change to a TH400 and gear vendors. Hopefully engine break in and tuning will be finished in a couple weeks and I'll have some numbers to post.

Joe

Sounds good. Joe at Westminster trans was a big help when I had my auto built and had some info regarding Suncoast. I also had a problem with first gear going by too quick and pulled some timing to soften it a bit.

Good luck and have fun!

Ron

 

[JTS VENOM PERFORMANCE]

:congrats: :congrats: :congrats: :congrats: :congrats: Do you have any idea how happy I was to see this post for you bo?


I dont hav an answer on timing, I suck at tuning


but man!!! so freakin happy!!

call KC at underground, he will usually cll ya back, 704-361-1444 explain in the message what ya need, and where it was, and mention my name(that might be a bad thing ) and maybe he will give ya a hlla back bo


but DAMN so freakin happy for ya dude!!!!!!!!:congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats:

They shold be tuning B Exxons truck now, so I know he should know off the top of his head, and it has NOS also

 

[Scrambler1]

Thanks buddy!! It's been a long road to recovery but I'm getting close!

Just make sure your ass is ready to be waxed when you come to Panama!

Joe

 

[JTS VENOM PERFORMANCE]

Why is my butt too hairy for ya

I mean if ya want some man sex, and for me to wax my ass, hell dude all ya got to do is ask :marchmellow: :marchmellow:

Bare ass it is then