Suck N Blow Monte

[DRIVEN]

That Corvette. What'll you bet that the entire build started with those rear wheels being too cheap to pass up at a swap meet?

 

[Turbo Zach]

So, first off I'm no tuning expert but let's try a couple things.
Cruise timing should probably be more like 35*

Cruise afr should be 14.7-15.2 ish. It's pig rich right now.

Wot timing is pretty aggressive if it were in my setup it would absolutely detonate if tuned like yours. Go safe first. Try 10 degrees and inch it up. Detonation is bad juju and it's actually happening before you can hear it. I see that it has a boost retard feature but to keep it simple for you at first just set the WOT timing so it won't go past that point.

Wot afr...11.5 is as lean as I will let mine ever get. Command 11.0 and see if it likes that. A little extra fuel helps stave off the detonation too.

I don't buy into the turbo or the efi unit being too big. Big turbos are your friend as they make really good volume for a given psi of boost and therefore have a cooler air charge which is less prone to detonation. You can tell the sniper to run leaner and it will. It's not too big. I share your frustrations with tuning!! Slow and steady, write everything down. That controller makes it way easier than say HPtuners. Try these few suggestions and let us know how it goes.

I appreciate the advice and I will probably try some of that. I don't know when I will have time though. More I think about it, it may be inconsistent timing. They is a lot of people that have had trouble with a magnetic pickup and the Sniper. I will watch the timing next time I have it out. If nothing else I can get a MSD BTM ignition box and do away with the veritable timing if I have too. I just need a hole day I can drive it and tune it. That probably will not happen till fall.

That Corvette. What'll you bet that the entire build started with those rear wheels being too cheap to pass up at a swap meet?

That is kind of what I thought too. The back wheels were dirty and pitted for being custom made jobbies. Neat though!

 

[Turbo Zach]

So, first off I'm no tuning expert but let's try a couple things.
Cruise timing should probably be more like 35*

Cruise afr should be 14.7-15.2 ish. It's pig rich right now.

Wot timing is pretty aggressive if it were in my setup it would absolutely detonate if tuned like yours. Go safe first. Try 10 degrees and inch it up. Detonation is bad juju and it's actually happening before you can hear it. I see that it has a boost retard feature but to keep it simple for you at first just set the WOT timing so it won't go past that point.

Wot afr...11.5 is as lean as I will let mine ever get. Command 11.0 and see if it likes that. A little extra fuel helps stave off the detonation too.

I don't buy into the turbo or the efi unit being too big. Big turbos are your friend as they make really good volume for a given psi of boost and therefore have a cooler air charge which is less prone to detonation. You can tell the sniper to run leaner and it will. It's not too big. I share your frustrations with tuning!! Slow and steady, write everything down. That controller makes it way easier than say HPtuners. Try these few suggestions and let us know how it goes.

I had a little time tonight and I tried messing with my tune. I tried your suggestions. The engine ran like sh*t. Ended setting it up like this and it worked a lot better.

I took pictures of the AFR's, but they are too blurry to see. 14.1 at idle, 13 at cruise, and 11.5 at wot. Still getting a lot of knock on the gauge. It is pretty consistent, but if you back out of the throttle and get back into it it goes away. Fauls knock? I am only getting about 10 psi boost right now. Don't really think it should have any real knock at that low of a boost level. I did see kind of what is going on with the low-end power. At idle or low rpm under a load the timing is jumping around and way retarded, like 0 or 9 degrees from 17 degrees and then it jumps back up. What would cause this i don't know? I am thinking about buying a BTM MSD box and doing away with the Holley timing control for now. The problem I see with that is my distributor does not have any advance any more. It is locked out. I bought it that way. What do you guys think? On a lighter note, I took the car to town to get gas for the skidloader. Every were I went people were giving me the thumbs up. Even a bike rider going down the highway gave me a thumbs up. I must be doing something wright i guess.

 

[81cutlass]

13 cruise is still rich. 14.5-15 is a good goal.

11.5 WOT is good.

Does it run bad at 14.5-15 or will it just not get there?

Cruise timing should be higher than 20. Does it use a vacuum advance like an old distributor?

 

[motorheadmike]

That'll do it.

Try:
13.5:1 idle
13.7:1 cruise
11.5:1 WOT

And set your boost enrichment to 0.2; if you hit 10psi that give you about 11.1:1 as a safety margin.

As for the Accel Enrich - start small, probably 20lb/hr, and roll slowly into it.

Yeah, 13.0 at cruise is a bit rich - Speed Density systems tend to like it a bit rich to compensate for the lack of resolution in the fuel tables. Try leaning it out a hair - that engine will run at 16:1 at light loads if you command it to.

 

[Turbo Zach]

13 cruise is still rich. 14.5-15 is a good goal.

11.5 WOT is good.

Does it run bad at 14.5-15 or will it just not get there?

Cruise timing should be higher than 20. Does it use a vacuum advance like an old distributor?

The reason I didn't lean it out more is because when I let off the throttle it gets leaner by 3. So 14:1 it will go 17 when I let off. I thought that might be bad? There is no advance in the distributor. It is locked out. If I had the parts to put back in it would be mechanical advance. When I bump the timing up it does not run as good. Any thoughts on the knock or the timing drop at low RPM?

 

[81cutlass]

17 at decel when you let off is OK. As long as the idle sticks around 14.5-15 you are fine.

New engines use something called DFCO (deceleration fuel cutoff). That kills the injectors when you are coasting since the driveshaft is backfeeding the rotation neeeded to keep the engine running.

If its 17 at idle when you are coasting but picks back up to 14.5-15 as soon as you tap the throttle or come to a full stop, that is fine. It's in factory stuff for fuel mileage, and although it might not be programmed that way for the aftermarket setup, if it happens to do that it's a happy accident and as long as the engine doesnt die its just going to get you better mileage.

 

[Turbo Zach]

Well I found some time tonight to play around with the car and get bugs splattered all over the windshield. I found my base timing was way off. I put my timing light on it. It should have been reading 15* but was not on the chart. I think it was advanced too much. I moved the distributor before I figured out how to run my timing light so I am not sure. I ran the car up and down the highway and adjusted my settings a little bit. This is were I am at right now.

It runs a hole lot better! Pulls like a freight train now, and I am only getting 7-10 psi of boost. I can only imagine what 20 psi would be like. I still have some issues yet though. It will not fry the tires!? When you try and launch the car or do a brake stand the timing backs of to 0 and once you get rolling it jumps up to were it should be. Any ideas? Second issue is I am getting into the red on the knock gauge at 7psi of boost. Is it faulse knock? I have a hard time believing it is getting that much knock at that low of a boost. Timing did not change the gauge reading any. Even with the hesitation off the line I bet I am pulling a hundred MPH in the quarter mile. It gets up and rocks. MrSony better look out! I am starting to see what the stink is all about when people talk about Grand National's now. I would post a video if I knew how. P.S. The hell with that draw though crap. Throw it in the junk and blow through!

 

[MrSony]

I drove the old girl to work Friday.View attachment 91315 It is running pretty good. It does not have the power yet I think it should though. It drives good and will get up for a driver, but it should have more. I think I can take a certain some one with a Buick 350, but don't know if I can beat a four door pig.

Thems fightin words...
I live my life an 1/8 mile at a time. For those 10 or more seconds, I'm free.
😛
PS: 4 door was my old tbird. rip 1970-2016

 

[MrSony]

Here is some pictures of the car show.View attachment 91699View attachment 91700View attachment 91701View attachment 91702View attachment 91703View attachment 91704View attachment 91705View attachment 91706View attachment 91707View attachment 91708

where the hell are all these shows at?