ALOT of timing! no detonation

[quickstrike]

more of a statement I guess than a question.

I am running a vortech s-trim superchsrger that is non intercooled. I see about 14psi with hot input air temps around 210* at the end of the track.

I am using sunoco purple(110 octane). Target A/F about 12-1. Whats freaking me out is I have been slowly adding more and more timing trying to creep up on the HP peak without blowing head gaskets, and I am now up to 29* at full boost and 6000 rpm. How can this be?

car does not feel like it has slowed due to predetonation, and plugs look just fine(no red specks or maroon tint to them). Is this weird or has anyone else had a similar experience?

Kinda scared to go any higher. I will be going to the dyno in the morning, to do some testing to see if 11-1 or 12.5-1 A/F ratio or anything in-between works best. Maybe I will learn something there.

Randy

 

[Taffy]

I would be interested to see how far the timing can go and still make HP. The only problem is that the higher the timing goes, the higher the cylinder pressure goes. That is when HGs blow. I am gonna do some dynoing on my Integra to see how low I can take the timing and not lose power so I can run more boost on pump gas. The dyno sheets I have seen show that after a certain advance, the Honda head (B16A) does not make any more HP, just adds more cyl press. Good luck, ERIC.

 

[bruce]

Originally posted by quickstrike
more of a statement I guess than a question.
I am running a vortech s-trim superchsrger that is non intercooled. I see about 14psi with hot input air temps around 210* at the end of the track.

Sounds like you missed, the engine's sweet spot.
Are you making any more HP?.
If you're not seeing any actual improvement, why are you adding timing?.
The idea is to run the least amount of timing consistant with best best performance, NOT to just run as much timing as possible.
Sounds like your about ready to knock the corners off of the pistons.

 

[quickstrike]

the car goes faster and faster every degree I add. Had the car stopped making improvements I naturally would stop and back up. If I remove timing car slows a little (ET/MPH) I would have expected to have some signs of detonation at this point, but I do not. I am certainly not an expert but I am all to aware of what detonation is and can do.

I will learn more from the dyno in the morning, as this will take the human error out of the equation and add some consistency.
I suspect It is about maxed out in timing at this point. I am running rich with fuel, and that is more than likely cooling down the cylinder temps slightly. This would account for the ability to run more timing than say a car at 12.5 to 1 A/F.

I know this theory is used by the turbo guys more often than blower crowd, but it seems to work for me as well.

Randy

 

[Taffy]

How much compression ya got? If you are at 8.5 to 1, then 15 PSIG boost is not much. I do not think that even with that much timing you are running into too much cyl press if indeed you are running low compression.
When is the intercooler going on? How about more boost? ERIC.

 

[quickstrike]

Yes thats true. It is just about 8.7 to1 compression. That would account for lower cylinder pressures and more timing. Hadnt really thought about it that way.

I would love to have an aftercooler, but there are too many other things on the priority list.

R block
bigger blower.
tires
suspension
etc etc etc............

Headed to the dyno now, once I find fuel for me and the car!

Randy

 

[Butch]

It seems pretty common to have the crank reference angle set wrong. Have you verified that your timing in FAST agrees with your timing light?

Maybe you think you are running 29 degrees but only running 20 or something. I have seen that happen several times lately.

Patrick Rubio's car at the Nat's and Geno's new motor when he first ran it. Both were off by something like 10 degrees!

Butch

 

[quickstrike]

Yeah that was the first thing I thought of, but it was correct.
During the Dyno tune session The tuner said it wasnt at all uncommon to have the timing that high or even a little higher, on a small block ford with low compression(8.7-1). Car made good power even with the heat and humidity.

seemed to like 12.3 to 1 A/F the best with 29* of timing at 6000 RPMs with 14lbs of boost.

last year car made 552 RWHP this year only made 500 RWHP, but now has an automatic and alot hotter temps. TQ was up to 570 tho. increase from last year.

overall very happy.
Randy

 

[Butch]

Sounds about right.

Our Turbo cars seem to like something in the 12.0 - 12.2 range with 26-29 degrees of timing, but alot more boost

This is based on my limited exposure!

Butch

 

[GNandGS]

Combustion chamber design can do a lot also... as can what head you run.

S

 

[NoSlix]

When the motor was built, was a dial indicator used to determine actual TDC on #1? It's not uncommon for the timing marks on the balancers to be WAYYYYYY off. My current motor always liked a LOT of timing......or so we thought. At the last rebuild, my new engine builder found that the balancer(Romac) was exactly 10 degrees off. So when I was setting the base timing at 10 degrees, it was actually 0 degrees. He said he sees that frequently. Something to check. Another thing........you're motor probably makes peak torque at 4800 or so, right? What's your timing look like at that point? Peak torque is usually where you should be really concerned, because you can add in a good bit of timing after peak torque.