Boost and timing

[Vacuum 6]

With an alky system how much timing and boost are you guys running on 93 pump gas? Just want to see what people are typically using.

[Jim A.]

See signature. Boost was 22.5#.

[Lonely WE-4]

so does the alky like higher timing, or higher boost, id like to know that. has anyone even tried it yet?

[tim87tr]

With an alky system how much timing and boost are you guys running on 93 pump gas? Just want to see what people are typically using.
I made a couple passes Saturday on 24 psi and the Razor progressive :top: . I think I could go up a couple more psi boost also. This is the first alky system I used and just installed it a couple months ago.

Used a TurboTweak 93 street chip, lower timing of 21/19. He said I could use a couple more degrees timing if I wanted, but I think I'll stick with this, it works, and maybe is a bit more conservative for tuning error.

[stevemon]

47 points. (adding 24* timing and 23 lbs of boost)
Using 116 Maximal I run 30* timing & 23 psi = 53 points.

Best ET for alky is 12.65 and the next week it went 12.25 on 116.
(best of 11.98 / 7.62 & 113.46 mph on a 1.62 sixty.)

With my car, I don't consider a point number under 50 or ETs in the mid 12s to be racing so I prefer good fuel over alky.

Combo is below.

[Razor]

Yes and no. The lower the timing is run, typically the safer the tune is. You can run 30 degree's timing on alcohol..tho your chances of encountering detonation is way way higher. Give you an example of a situation whereby extra timing is run, and an example of where its not needed.

Stock turbo/stock longblock at 23 PSI boost. Once at 23 PSI its out of its range efficiency wise.. only way to make more power.. add timing.

Modded motor, heads, cam, bigger turbo, exhuast, IC.. your at 23 PSI boost. Leave the timing alone, crank the boost up. You'll make more power on boost vs timing.. and be a lot safer.

So this is what alky chips do... we'll throw a bunch of timing on 1st and 2nd gear, then pull it out on 3rd/4th. Hence the designations 23/21 24/20 etc. The higher timing in lower gears makes more burst and gets the car moving down the track faster.. once in third..and running boost.. the high timing is no longer needed.

So it depends on your combination and what is going to be needed to maximize it. No cut dry approach due to variables in place.

HTH

[Vacuum 6]

Yes and no. The lower the timing is run, typically the safer the tune is. You can run 30 degree's timing on alcohol..tho your chances of encountering detonation is way way higher. Give you an example of a situation whereby extra timing is run, and an example of where its not needed.

Stock turbo/stock longblock at 23 PSI boost. Once at 23 PSI its out of its range efficiency wise.. only way to make more power.. add timing.

Modded motor, heads, cam, bigger turbo, exhuast, IC.. your at 23 PSI boost. Leave the timing alone, crank the boost up. You'll make more power on boost vs timing.. and be a lot safer.

So this is what alky chips do... we'll throw a bunch of timing on 1st and 2nd gear, then pull it out on 3rd/4th. Hence the designations 23/21 24/20 etc. The higher timing in lower gears makes more burst and gets the car moving down the track faster.. once in third..and running boost.. the high timing is no longer needed.

So it depends on your combination and what is going to be needed to maximize it. No cut dry approach due to variables in place.

HTH

Has anyone tried running a high timing chip (~27º) and ~24# of boost with lower than req'd gas mixture and used their alky kit to provide the proper octane? Hypothetically this setup (chip and timing) really calls for straight 100 octane. Will an alky system provide additional octane to make the mixture seem as thou it's 100 octane? Is this practical or is an alky kit specifically designed for low timing and high boost?

[Vacuum 6]

Come on guys…no one as thought to use an alky kit for this specific purpose? Little help here Razor or Steve.

Please read the below.

Has anyone tried running a high timing chip (~27º) and ~24# of boost with lower than req'd gas mixture say 97 octane and used their alky kit to provide the proper octane? Hypothetically this setup (chip and timing) really calls for straight 100 octane. Can an alky system provide additional octane to make the mixture higher? Is this practical or is an alky kit specifically designed for low timing and high boost?

[SMC]

Vacuum:
Yes, the alky will raise the octane of any fuel that is lower than say 100. When I was track thrashing our test mule car a couple years ago I was running a radical for the time 29 degree race chip @ 24 psi on 94 octane. I was out of injector, out of turbo, EGTs were too high, and I was definitely tickling the knock sensor........but the car was flyin for the mods it had! The point is the alky held it together. That car never blew a head gasket till after I sold it and the fool ignored his "low alky" light...... :stupid:

Hp can come from timing OR boost, some people just prefer one over the other. Either way the alky will do it's job.

[kgouldsk]

I want to make sure my understanding of all this is correct, so if the experts would point out any errors, I'd appreciate it. I'll try to be clear and not ramble.

The thing we're fighting all the time is fuel volatility. We're looking for a nice, controlled burn in the cylinder with a smoothly advancing flame front. Under ideal conditions, this occurs, and its regularity and predictable nature is what lets us settle on a particular timing advance as being optimal. Any time we get a variation in how the flame front propagates, we have to make accommodations for it - specifically, when we get any combination of the following:
- low fuel octane
- cylinder/charge mixtures temps higher than norm
- higher compression due to things like carbon buildup
- higher cylinder pressure from higher levels of boost
- higher cylinder pressure due to engine load (higher gears, thus less timing in higher gears)

the mixture will tend to go from having a nice even flame propagation with full spread to the whole cylinder, to an erratic, explosive ignition. This produces overly high and uneven pressure waves in the cylinder, which can be catastrophic depending on severity. When we detect this happening, we can retard the timing - this doesn't stop the aberrant burn pattern, but makes it so that the cylinder is sufficiently advanced before we spark it that it reaches tdc before the pressure wave creates any misery. If you look at a graph of cylinder pressures during knock, instead of this nice, smooth pressure curve, you see all kinds of strange jagged spikes striking far higher than normal - it's definitely not a linear effect.

The other point I want to make sure I understand is that in regular, no-knock operation, changing timing has the effect of shifting our power curve. Advancing the timing will tend to shift the power curve to higher rpms, as we get more benefit of the earlier firing when the engine is running fast and we get our full burn occuring closer to tdc. At low rpms with advanced timing, we are getting peak pressures a little too early and are not getting full benefit of the fuel/air ignition, which is also giving us higher cylinder pressures (but not erratic ones, nice and smooth so not terribly dangerous in moderation).

So advancing timing can gain us some mph/power on the top end. But when we start boosting to high levels, or have low octane, or are running hot, or with carbon buildup, we start to run into the risk of that erratic burn, which is going to give us knock.

Does the engine module vary timing at all across the rpm range? It would seem we should. If so, what is the static (example 23 degrees) advance we're talking about - is that 23 degrees total advance at redline, idle, or where?

Ok, go ahead and straighten me out, clarify, add. Thanks.

Kevin

[Razor]

The timing tables are programmed within the chip. Based on load and rpm will determine the particular table being used. When we use the number 23 degrees.. it relates to timing using the load value above 224-256(max) and RPM's typically higher than 3600 RPM's. Tho depending on chip programmer, that RPM may be as low as 3200 RPM. Kinda like the BLM table. Tho the BLM table has 16 slots, the timing table has 255 slots 17x15.

Example RPM 4800 load 32 can equal 50 degree's timing, tho as the load goes up, the timing comes down.

[Vacuum 6]

With an alky system how much timing and boost are you guys running on 93 pump gas? Just want to see what people are typically using.

Anyone else? There should be 100s of posts here. Also please include any motor modifications (bolt on and/or internal).

[Razor]

Anyone else? There should be 100s of posts here. Also please include any motor modifications (bolt on and/or internal).

How bout you list what mods you have, we then guess what will be your limit.

And outside air temps? elevation? EGT's? O2 readings? air density? humidity? was the timing variable or fixed?

See there is a huge difference between running boost and making power. As it requires tuning, tuning which is specific to a particular car/combo.

Too many variables to matter really.

Ive seen Buicks that claim 26 PSI and only run 13.50's, and i've seen Buicks claim they run 11.0's at 17 PSI.

[Vacuum 6]

How bout you list what mods you have, we then guess what will be your limit.

And outside air temps? elevation? EGT's? O2 readings? air density? humidity? was the timing variable or fixed?

See there is a huge difference between running boost and making power. As it requires tuning, tuning which is specific to a particular car/combo.

Too many variables to matter really.

Ive seen Buicks that claim 26 PSI and only run 13.50's, and i've seen Buicks claim they run 11.0's at 17 PSI.


I am not trying to “guess people’s limits". I realize there are many many variables. I started this post because there are a lot of threads with people running 10s on alky unfortunately that’s not me. I just wanted to see the different setup people are using with alky. It’s nice to see what the next guy is doing.

My set-up stock motor heads and intake, TE 60, 12” 2800 stall, 42# injectors, 3” DP, HD actuator, walbro 340, CAS V2 FM, RJC power plate, BGC 2 3/4" exhaust, typical recipe stuff, 24° with 22# on 93 pump gas via denaturized alky.

Signature time…80° weather, elevation 600’ above, EGT do not know, O2s 80-76, knock 0°, air density and humidity…forgot my portable weather data system :arco:, variable timing as far as I know.

[Razor]

My set-up stock motor heads and intake, .

Mid 11's your out of juice on alky. maybe if your lucky an 11.4xx at really high boost, high timing. Your low 12 second time is typical for a stock motor, small turbo, and small injectors.

On racegas with high timing, high boost, excellent 60 foot like a 1.4-1.5 may dip into the 10's. Not on 009's tho..

The basic recipe for 10's holds true, to do it on alky.. must have a custom chip, a lot of alcohol, high boost, much larger turbo, and the stock heads and cam.. forgetaboutit. Figure 125 for trap speed. Figure how to get to 125 MPH.. you'll get your 10 second pass with a little traction.

Since alcohol chips run less timing than race gas chips.. you'll need additional boost to make up the difference.

So what are cars running with your combination, typically low 12's in normal weather. In great weather high 11's.

If you live in Florida.. thats what your car would run. Up north in MD for example, 55 degree temps.. an easy 3 tenths faster.

[Vacuum 6]

Once again, I did not intend this thread to turn into “let us guess your setup’s limit” but that is the direction it went. Anyway thank you Razor for the information. Sorry if I rubbed anyone the wrong way.

[Razor]

No rub.. its alrite.

I've done plenty of kits and seen how different combinations work. From mild to wild. Hence why I offer my humble opinion.

You can get individual info, or you can get info from someone that lives the stuff.

Either way, you'll get the info you need :arco:

[Vacuum 6]

Can anyone else give information on the timing and boost they are running with 93 pump gas and alky?

[Vacuum 6]

Can anyone else give information on the timing and boost they are running with 93 pump gas and alky?

This year I've played around with my DIY alky kit and now I'm running 26# with a TT 24*/22* chip.

[Turbo Archie]

But whats your MPH (horsepower) ???

[Vacuum 6]

But whats your MPH (horsepower) ???

You know I have not gone to the track yet. Once I do I'll post something.

[cablebandit]

f-body with turbos that combined max at about 750 rwhp...dunno the equivalent single turbo size. Anyway, right now I am at 15psi with 20 deg timing with SMC alky and 93 octane. 10.12 @ 137 3820# raceweight

[Turbo Archie]

you run 137 on pump gas??

Has anyone transplanted an LS1 into a G-body??

[cablebandit]

pump AND methanol. I dont think a lot of people give alky enuff credit. Learned it all from you guys!!!!

[Vacuum 6]

I dont think a lot of people give alky enuff credit.

I agree.

The more and more I play around with alky the more and more I love it! Forget race gas.

[Robbie-87plz]

I wouldn't throw race gas on the side...Alchy is better than pump gas but I still think race gas has its' merits... :elefant:

[Turbo Archie]

I wouldn't throw race gas on the side...Alchy is better than pump gas but I still think race gas has its' merits... :elefant:

Wally doesn't race so.........

[Vacuum 6]

Wally doesn't race so.........
My car runs so...get your car on the road!

[Turbo Archie]

I was werkn on it today thank you.

should be running monday.

[Vacuum 6]

should be running monday.

Got it running?

[Turbo Archie]

I didn't say what monday.

[Vacuum 6]

I didn't say what monday.

Way to cover your butt.

[Turbo Archie]

RSD all day this sat. Lets bring your shit!!

[Vacuum 6]

RSD all day this sat. Lets bring your shit!!

Jimmy is doing the trans. Hope to have it back this weekend. Going racing at the Grove July 17, Chicagoland Buick Club will be there.