SMC single nozzle users question

[V6POWER]

How do you keep the O2s down at launch? My turn on point is 15# boost, my pump speed is 9, and my static FP is only 40. My O2s are in the 870-880 range at launch and this just kills low end power. They are about 790-800 at end of run. The car does not bog at launch, but I know the richness is not helping low end. I don't need to turn down the FP because the top end O2s are fine. Any suggestions? TIA.

 

[The Darkside]

As you can see by my mods below, I have a similar setup as the one you have & I have exactly the same problem with my o2's.They start off around 880 & drop down to around 810. My car's fuel pressure is @ 39 line off, pump speed is around 8, turn on around 15.Car feels sluggish off the line.
What boost level are you running & with what degree timing chip? Mine is a 23 degree chip & I'm running @ 24 lbs. boost.




The Darkside

 

[V6POWER]

I went from a 21* that I could run 24# without knock to a 23* that I can run about 22.5# without knock.

 

[blackbuick87]

Unless you are launching at 15 psi alky has nothing to do with your O2's at launch

 

[The Darkside]

So should it be able to be corrected by lowering fuel pressure or is it a chip issue?



The Darkside

 

[blackbuick87]

Darkside if you are still running the Jay Carter chip contact him and see is he can reburn it to be a little leaner down low. This will help your spoolup since rich = slow spool.

Look Quick I see you have a Translator with Extender 100 chip. I am not familiar with this chip, but if you have any questions I would talk to TurboBob.

There is a fine line between rich enough and too rich. All engines run richer when you get on the gas down low to make up for the temporary loss of vacuum. But too much fuel causes havoc with turbo motors.
Some other things to check for are vacuum leaks or header cracks (any exhaust leak b4 the turbo) these will cause the exact condition you describe.
Finally the stock O2 sensor is not accurate enough on its own to determine richness, keep this in mind when using the data from it.

 

[V6POWER]

blackbuick87--I am working with Bob on this issue and hopefully we can get it resolved. He made a point though that this is a constant flow system so at 3,000 rpm you get two times the alcohol in the cylinder than at 6,000 rpm. If the alcohol is right at the top end, it will be too much at the bottom.
Regarding the header crack and vacuum leaks, I had Dwight Hayden repair my header and I also periodically check the engine for vacuum leaks by listening for changes in engine idle while spraying carb cleaner.
I also have an EGT gauge that I use, not just the O2 readings.
All these problems occured when I moved from FL to NC and I put on a cat. conv. to pass emissions. I have since removed the cat. but the car is still rich. I guess I need to move back to FL!

Thanks for your reply.

 

[blackshoebox]

I have been experiencing similar tuning issues with alky. Rich on the bottom and lean and mean up top. I am thinking of going to 50/50 water/alky mix to see if that helps, or just turning the alky off all together and just running c-16, and tuning for the race fuels richness rather then the alky.

Alex

 

[V6POWER]

Alex--The 50/50 mix is another thing that Bob told me to try. I forgot about that. I have thought about going back to race gas also, but I just hate giving up the boost from the alcohol (OK, I admit...I'm an alcoholic!)

 

[blackbuick87]

Look Quick I think the best solution would be to get the dual nozzle kit from Steve. Since you are obviously doing hi-psi launches, you could have two small nozzles instead of one big one. Set the first one for about 12psi and the second for 18psi and see if that helps

I think the upgrade is pretty cheap. Guys that go fast on alky usually have four or five nozzles, not one

 

[V6POWER]

Bob --- I am only doing 5-7# launches but the dual nozzle would probably help my problem. Thanks again.

 

[VIN7]

Jim,

The dual nozzle from smc is just that, two nozzles spraying instead of one. You would need to get another hobbs switch and wire it to a solenoid in order to get a progressive alky system. If I ever get back to tuning my car, I am going multi stage with the aquamist nozzles and solenoids. Maybe work on using the 3rd gear trigger on the BstC to enable additional alky for the last half of the quarter. Maybe one of those MSD ignition boxes with rpm triggers would work too. Search aquamist in this section and there is a post about how to get some affordable solenoids.

Mike

 

[V6POWER]

Thanks for the info/clarification Mike.

 

[Turbo__Tim]

You can upgrade to Aquamist lines, solenoid, and nozzles for about $200.
Here is the way I did it.

First install the adapter to go from Steves line to 10mm line. From there you go to a 'Y' connector. One side goes to another 'Y', and then into (2) 1 mm nozzles. This is the first stage and will activate spray into the system with the same settings you have for the SMC system.

The other side of the 'Y' feeds into an aquamist solenoid that is activated by a seperate Aquamist 'hobs style' pressure switch that is spliced into the vacuum line right beside the SMC switch. The output line from the solenoid goes to a 'Y' connector. One side of this 'Y' feeds a 1 mm Aquamist nozzle, the other a .8 mm.

Always run the 'hot' (positive) side to the hobbs switch, and to the solenoid, then use a common ground for activation.

I bought an interior light to set up the Aquamist hobbs switch. One side of the light plugged into the cigarette lighter, (for convenience), the other side runs to the ground side of the hobbs switch. An allen wrench adjusts this about one turn per 1 psi.

You could use a tap they have for drilling, and installing the threads for the nozzles, but it doesn't work all that well with the thin walled pipe. I ended up using J.B.Weld on the nozzles anyway.

The nozzles are 2 piece, so be sure to tighten them gently. A spot of rtv there will help that....

I put all the 'Y's, and solenoid in the same place, and ran the 4 lines to the up-pipe. I think it looks better that way...I used the 18" feed line from SMC to go from the bottle, under the overflow canister, and put all the y connectors, and solenoid there, just on the other side.

Due to the much smaller amount of alchy mix delivered through each nozzle, (about 1/4 the amount each) you will activate 4-5 psi before you see knock, and the second stage should activate about 4-5 psi after that. So about 12 and 18?

Use a 50-50 mix, denatured and water..

Aquamist dealer- Ask for Brad- (816) 333-6582

 

[V6POWER]

Tim--Thanks for the great explaination. That sounds like a real nice set up and should definately help to 'stage' the alcohol for better low end performance.