3.5" Pulley on Whipple and 93???

[rio16]

I run the 3.625 on 91 (CA) with no additives and no adjustments on the Whipple tune and I have zero knock. Leads me to believe you shouldn't have a problem on 93. Shawn (@Roh92cp) is going to be trying the same thing here soon. Reach out to him for what testing he ends up with.

Going to hop on this. Hopefully this weekend :doh:

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[Foxracing19931]

IMO 93 octane isn't enough to support 13 - 14 psi and that is what the 3.5 pulley should provide at around 7800 rpm at sea level. 1 psi is worth approximately 20 - 25 hp and 1 deg of timing is worth about the same, given those conditions I would rather run the 3.625 pulley and let the computer run more timing through out the entire rpm range. I would venture to say that you would make more power due to the timing not being pulled out.

I know 93 isn't enough that's why I'm using octanium and should be like 100ish octane it's always adding timing through rpm I never saw a real drop in timing and always stayed around -2.00+ knock

 

[Roh92cp]

I reached out to Dustin last week about the 3.5" on 93 and he says it's possible, but every car is slightly different in its ability to resist knock. He said to try it with good 93 fuel and watch for knock (I have Ngauge) and if it knocks take the pulley off and go back to the "3.625. I asked about running it with octane adjust on in flight controls and he said no if it doesn't live on its own then it's not worth it as octane adjust will kill too much power in timing reduction. Octane adjust is a safety measure for bad fuel, not really for pulleying down and turning on to make power, won't work!

I do however have an alternate plan. If it can't live completely on 93 alone without pulling timing then I have a methinjection kit installed and will try a small shot of 4gph into the Whipple after the throttle body. I believe this will still be safe even if meth fails it will only be a little timing and knock that would be pulled as it would already very close to safe with 93 alone.

 

[Superman15]

I know 93 isn't enough that's why I'm using octanium and should be like 100ish octane it's always adding timing through rpm I never saw a real drop in timing and always stayed around -2.00+ knock

Man.. Octanium at each fill up?? That is a lot of dam money. Why not just slap that 3.625 back on, and save that money to go e85? I mean if you are a track guy I get it, but for DD, I just don't see the value in that.

 

[Foxracing19931]

Man.. Octanium at each fill up?? That is a lot of dam money. Why not just slap that 3.625 back on, and save that money to go e85? I mean if you are a track guy I get it, but for DD, I just don't see the value in that.

I always daily the 3.625 pulley...I've done octanium 3 times just to test things out with different pulleys for science of course :headbonk: but on the plus side I am saving for a fore system in the mean time

 

[Roh92cp]

Pushing the limits of octane with smaller pullies is easier with these cars becuase excellent knock control strategy. I'm coming from the pushrods Fox body and we don't have much play room, you knock you go boom real fast. Dustin at Whipple is testing a new cal with less timing like 15 instead of 18 and he is running a 3.5" on 91 with no knock right now. I'm not saying we should all be running on the verge of engine melt down, but I think running close to the edge of the octane limit with these cars is easier.

 

[Superman15]

I always daily the 3.625 pulley...I've done octanium 3 times just to test things out with different pulleys for science of course :headbonk: but on the plus side I am saving for a fore system in the mean time

Ok cool man. I was thinking octanium on every fill up, with regular daily driving, must get pretty dam expensive. I also want to go fore system. Maybe next year.

 

[Superman15]

Pushing the limits of octane with smaller pullies is easier with these cars becuase excellent knock control strategy. I'm coming from the pushrods Fox body and we don't have much play room, you knock you go boom real fast. Dustin at Whipple is testing a new cal with less timing like 15 instead of 18 and he is running a 3.5" on 91 with no knock right now. I'm not saying we should all be running on the verge of engine melt down, but I think running close to the edge of the octane limit with these cars is easier.

Have to admit, I'm not sure I understand the goal here. You go smaller pulley for more power, then reduce timing, thus reducing power..? What am I missing here? I am sure I am missing something, as there is obviously a goal with this effort. I just don't see it.

 

[pro 5.0]

Have to admit, I'm not sure I understand the goal here. You go smaller pulley for more power, then reduce timing, thus reducing power..? What am I missing here? I am sure I am missing something, as there is obviously a goal with this effort. I just don't see it.

They are probably trying to find out how much timing can be run without knock on the 3.5 pulley and 91 octane. When they know that a safe octane rating for the 3.5 pulley could be established, just a guess on my part.

 

[Roh92cp]

Have to admit, I'm not sure I understand the goal here. You go smaller pulley for more power, then reduce timing, thus reducing power..? What am I missing here? I am sure I am missing something, as there is obviously a goal with this effort. I just don't see it.

They are probably trying to find out how much timing can be run without knock on the 3.5 pulley and 91 octane. When they know that a safe octane rating for the 3.5 pulley could be established, just a guess on my part.

The goal is to take advantage of available octane with keeping maximum timing. So yes reducing timing to add more Boost could be diminishing returns, but I think in Dustin's case and others there is a sweet spot for each combo. A cars ability to run a siad amount of Boost and timing on a specific octane can be maximized and tweaked and may be a little different for each car.

 

[pro 5.0]

I reached out to Dustin last week about the 3.5" on 93 and he says it's possible, but every car is slightly different in its ability to resist knock. He said to try it with good 93 fuel and watch for knock (I have Ngauge) and if it knocks take the pulley off and go back to the "3.625. I asked about running it with octane adjust on in flight controls and he said no if it doesn't live on its own then it's not worth it as octane adjust will kill too much power in timing reduction. Octane adjust is a safety measure for bad fuel, not really for pulleying down and turning on to make power, won't work!

I do however have an alternate plan. If it can't live completely on 93 alone without pulling timing then I have a methinjection kit installed and will try a small shot of 4gph into the Whipple after the throttle body. I believe this will still be safe even if meth fails it will only be a little timing and knock that would be pulled as it would already very close to safe with 93 alone.

I run 91 octane and 1 full can of Torco this should put me at a
93 - 94 octane so basically without an N gauge I have no way of knowing if the computer is pulling timing or adding timing. I have never heard any audible knock mind you but without seeing it on a gauge I don't know if I would risk trying the 3.5 pulley. I used to run a AIS meth kit on a S197 with a 3.4L Whipple and I ran 2 nozzles with a 1 way check valve after the TB, the issue I had with it was that every time I got off the throttle to shift the engine vacuum would suck the nozzles dry and that would cause a lean condition when I got back on the throttle. AFR was 11.5 @ WOT then I would take my foot off the throttle to shift and AFR would be 15.94 when I got back into it. IMO if you are going to run meth injection it needs to be direct port to avoid this issue and also spraying meth through the blower has a distribution issue due to air turbulence which cause some cylinders to run lean just my 2 cents.

 

[jhatley7]

The goal is to take advantage of available octane with keeping maximum timing. So yes reducing timing to add more Boost could be diminishing returns, but I think in Dustin's case and others there is a sweet spot for each combo. A cars ability to run a said amount of Boost and timing on a specific octane can be maximized and tweaked and may be a little different for each car.

This. + fuel quality. Just because the shell station on the rough side of town sells 93, I doubt it will be cycled enough to keep quality. Then how clean are their holding tanks??

 

[Evo_Rob]

This. + fuel quality. Just because the shell station on the rough side of town sells 93, I doubt it will be cycled enough to keep quality. Then how clean are their holding tanks??

GasBuddy used to keep track of cleaning, refueling, locations, etc but ended their partnership with TopTierGas/com. Which really sucks because I used it twice a week when fueling up. Now there's really no good option for knowing for sure :/

 

[TooSoonJunior]

Just to add my own 2c here, on the boost versus timing question...one of the biggest factors is the efficiency of whatever power adder you have (centri, roots). Since the 2.9L is still WELL within its efficiency range at the 3.5" vs 3.625" pulleys, you don't get a marked intake and cylinder temp increase with the slightly higher boost, so therefore not a lot of timing should need to be yanked out to avoid detonation. Once you cross the efficiency line and start really heating things up, then you have to compensate almost equally with pulling back timing and its a zero sum game.

Reason I started this thread was it seems like you guys really aren't cranking these blowers very hard. I cranked the living hell out of my 2.9L on my 426ci hemi setup, turning it well over 18k at the top of each gear and it BARELY nudged up higher IATs and heat soak was still pretty non-existent.

 

[Roh92cp]

Just to add my own 2c here, on the boost versus timing question...one of the biggest factors is the efficiency of whatever power adder you have (centri, roots). Since the 2.9L is still WELL within its efficiency range at the 3.5" vs 3.625" pulleys, you don't get a marked intake and cylinder temp increase with the slightly higher boost, so therefore not a lot of timing should need to be yanked out to avoid detonation. Once you cross the efficiency line and start really heating things up, then you have to compensate almost equally with pulling back timing and its a zero sum game.

Reason I started this thread was it seems like you guys really aren't cranking these blowers very hard. I cranked the living hell out of my 2.9L on my 426ci hemi setup, turning it well over 18k at the top of each gear and it BARELY nudged up higher IATs and heat soak was still pretty non-existent.

I agree with these cars here for the most part are seeing lower Boost levels in comparison to what others have run on Mustangs, but we are at a higher compression ratio. I've run 17-22 psi on my last Fox Dart based 363 with at one point a 2.1L kenne bell with making 17psi turning at 24k at full song way beyond its efficiency. I then fabricated a 2.8l H series KB that was making 22 psi on the street. This was all on 93 octane with meth injection and of course my custom air to air setup that helped to run that kind of Boost. Point there are a couple people here running big Boost on these motor, but on E85 or race gas, but most are under 13 psi and there's still some room not much for timing vs cyl pressure within the octane limits to make power.

Here is my old customs setup running 22 psi on the street.

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