What kinda of timing and what boost you guys running cooled not cooled?

 

I think my base tune at the moment is at a total advance of like 24-25*'s ... can't remember which number but i'll look at the tune again.

I do have a intercooler but 24* total is pretty conservative in my opinion. On a low compression motor running like 15* of boost i would prolly run in that area (22*-24*).
Im just keeping everything on the safe side for now... and I still managed to blow a head gasket not 20 miles in after the turbo install.

 

You posted to this thread: https://www.camaroz28.com/forums/sho...d.php?t=536564 and what you read there from a number of people is true. From some reason, probably turbulence in the chamber, blower OHV motors require very little timing. As I mentioned there, having seen dozens of OHV V-8's with blowers on the dyno, they like 24-26 degrees. The power will drop off on either side. Slowly if you dial in more advance and quickly with less. This is not changed by IAT's, so intercooling has no effect on timing requirement that I have observed.

Rich

 

Posted this thread first. So when intercooling it really is just a density change that makes more power. But, doesn't allow more timing.

 

I am running a large FMIC, and methanol injection, with 15#'s of boost running 26 degrees of timing. I have a very agressive cam, and honestly the car would like to see more timing, but I like the tune where it is, as it is conservative, and keeping me safe.

 

It isn't that you can't use more timing. It is that more than 24-26 degrees typically does not increase hp.

Rich

 

Oh ok thanks. Road with no returns.

 

i am stock compression and was only able to get timing to 12 degrees without kr..now i am intercooled i was able to bump up the kr to 14.

 

We have tuned one with AFR heads and an F1R at 30psi. The fuel was VP C16 (117 MON). We ran the timing in 4 degree increments from 14 to 34 degrees and saw max hp in the 24 degree range. None of the boosted small blocks (both Chevys and Fords) wanted more than 26 degrees. I think the relatively small combustion chamber, the lack of an interfering piston dome and the high tumble and swirl induced by boost make for efficient combustion and thus not much need for timing. As a comparison, high CR BBC with large chambers and large domes usually want at least 40 degrees. I don't have much experience with blowers and big blocks, so can't comment on that.

Rich

 

so for something more along the lines of small boost numbers around <7 psi, you would still suggest about 25* in the 95 and 100 kpa boxes? BTW its a stock bottom LT1 w/stock compression ratio. Also, what to do about the rest of the map? should I scale the timing down from 100 kpa or leave everything else alone?

and im going to assume to start the timing changes where the engine actually starts producing boost @ WOT rpmwise but not below that RPM?

sorry if these seem like silly questions but im a newbie to F.I. tuning.

 

Hmmm. . . my experience is apparently very different from the other folks on the board. I've always gained power from timing increases. I've never been able to advance to the point of reducing power before running into detonation. Just an example was the single T76GTS on the carbureted 377 SBC. On an engine dyno, it gained power ever time we increased timing. It had GMPP FastBurn heads so I really expected it to like low timing, but I was wrong. The last step we made was from 28 to 30 deg and it picked up 30+ hp. At that point, we all ran out of testicular fortitude and left it alone. I've seen similar results in my car, which coincidentally is a very similar engine/turbo.

 

Reading your post reminded me of one car that was more like your experience. It was a SBF with Trick Flow heads and a Vortech YSi. We kept adding timing and it kept making power. One pull at 34 degrees and it took out the head gaskets though. It went out the door at 28 degrees and has been happy. However, when we analyzed what happened, it was also too lean on the run that took out the head gaskets. We were running 93 octane pump gas.

Rich

 

I run the stock timing tables (33 degrees at 100KPA) and pull 1.5 degrees for every pound of boost with my MSD BTM.

 

if I had a BTM that would be the obvious choice, but I dont. I do however have a 3 stage timing retard box that I bought to use later on when I spray and boost. I suppose I could use a hobbs switch to trigger a stage and pull a set timing amount under boost. I already have a MSD6A. Any thoughts on that? BTW, I have no regard for the stock bottom engine because it will be replaced later on and I have another one anyways, just looking to play and push the limit of the stock setup as cheap as possible with what I already have. I might need bigger injectors though and im replacing the pump with a walbro. right now I got 30 lb svo's, and the nitrous kit is a wet kit with a small shot at the moment on a H/C stock bottom.

 

hmmm,....anyone? ^

seems like a pretty good idea to me, anyone have any negatives to attempting this? I figure if I manage 5 psi and take out about 8* when the boost triggers the hobbs/timing retard stage I should be safe. And if I spray it as well, it will trigger my other stage to remove more based on the spray size. Right now its only at 75 shot.