Bad stumble with alky...

[im4darush]

I have a pretty straight forward alky kit on my car (made by coolingmist) that is currently set to come on at 10lbs. The pump is a 150psi variation of the sureflow, and I currently have denatured alky in the tank. Not mixed. 100% denatured. Problem I am having is a real bad stumble. It does not happen all the time, but when it does, the car stumbles real bad and just falls on it's face until I get out of it. Other times it will pull real strong and will not stumble. This happens at both WOT and part throttle. I would say, it wont stumble about 40% of the time. The other 60%, its real bad. Not a light stumble....bad to the point where the car begins to buck. Boost levels are not crazy right now. The needle will spike over 20, but settle to a steady 18-19 at WOT. When this occurs, car has an initial surge of power and then just falls flat to where I need to get out of it.

 

[im4darush]

I gave their tech support a call and they told me I am turning on the spray too early since it is not a progressive kit. They said to move it up to 15lbs or so and see if the stumble goes away. I guess I can give that a try, but then how would you explain a WOT stumble at 18-20 lbs? Anywho...let me know what you guys think.

 

[unix_punk]

Scantool? Maybe its too much spray for that amount of boost... Car running rich?

 

[Jerryl]

I gave their tech support a call and they told me I am turning on the spray too early since it is not a progressive kit. ...........

Not trying to start heated discussions about kits from different manufactuing outfits, but, I think you answered the question. The progressive just make a lot more sense if you think about it.

In my mind, non-progressive would be kinda like holding some LARGE injectors wide open well below full boost setting.

Edit:
Typically, the chip writer also removes fuel out of the chip based on the amount of supplied Alcohol.
The wring chip and/or adjustments to the turn-on point, will have a great affect on the way the car performs.

 

[im4darush]

More sense? Yes, I agree. Also more $$. Plenty of folks have good results with standard kits. I think its just a matter of dialing it in. Plus, a standard kit can be upgraded to be progressive at a later time if desired. For now I would like to know what would cause my problem. Too much spray too early?

They also told me that the pump psi is non-adjustable. Kinda strange as it looks very similar to the sureflow(only black) and has the alan screw on top that controls psi. Mine was turned WAY out, so Im not sure where a good starting point would be.

 

[Jerryl]

More sense? Yes, I agree. Also more $$. Plenty of folks have good results with standard kits.

Don't take this as a "slam", but sometimes you get what you pay for though.
You are correct, plenty of fast cars not running a PAC.

......Too much spray too early? ..........

Sounds like you have a good handle on your situation.

 

[im4darush]

The coolingmist kits come with nozzles that are rated in Gallons Per Hour. The smallest nozzle is .75, and they go up to 12. I have no idea what they sent me as there are no marks on the nozzle. Would you guys be able to tell me the size that would work best in my car? Its a stock turbo, stock injector car. Only minor mods like air filter, walbro/hotwire, dut-neck IC etc..So basically a stock car with mild mods.

 

[Dreamcar86]

I gave their tech support a call and they told me I am turning on the spray too early since it is not a progressive kit. They said to move it up to 15lbs or so and see if the stumble goes away. I guess I can give that a try, but then how would you explain a WOT stumble at 18-20 lbs? Anywho...let me know what you guys think.

Sounds like you have got it figured out. The alcohol is putting out the flame. Try the smaller nozzle and turn it on at a higher boost level. Alcohol takes time and patience to tune. Trial and error.

 

[GSX-PKV]

Maybe it has nothing to do with the alky? Before doing a bunch of changes, I'd try turning the alky off, putting in a couple gallons of race gas, and then test it at WOT to see if it still stumbles. If not, it's the alky tuning, if it still stumbles these are other troubleshooting issues to tackle.

 

[im4darush]

At the moment I am trying to figure out what the optimal nozzle size would be.

 

[salvageV6]

The M10 which many use successfully on the DIY kits with a Shurflo is 10GPH at 100 psi.

I would also try a pressure gauge on the setup to verify your spraying pressure at WOT.

And also do the suggested test of WOT with good gas and no alky. at a safe boost for that particular octane to make sure it isn't something else.

Search feature has lots of good information as well.

18 to 19 psi. boost doesn't require much alky. with a typical street or alky. chip.

You might want to try a resistor in line with that pump to lower the voltage and kill the flow a bit.

Or turn up the boost.

 

[im4darush]

I just found out that they sent me a 12GPH nozzle. They were nice enough to send out a 9GPH at no cost if I paid the shipping, so I will give that a try when it arrives.

When do most folks set the alky to come on when using non progressive kits?