Timing and Boost on a carbed turbo6

[techg8]

I changed up the Alcohol spray stup to incorporate it into a makeshift cowl style cold air intake.

I found a 2" tall Vector hood scoop (~13"x15") at Advance Auto #CZ277B. I cut a 6" square hole in the hood above the carb and mounted the spray nozzle off to one side where the scoop would cover it. Ran the Alky line thru the hood to it. The Scoop has 2 sided tape and sticks to the hood. I mounted it facing rearward partially because I was worried that facing forward it might grab enough air to get pulled right off the hood.

The carb top sits 3.5"-4" below the hood.

I cut the center out of a carb cap like this http://www.summitracing.com/parts/mor-65802 and used it as a spacer on top of the carb. Then I used the base of an Edelbrock ProFlo http://www.summitracing.com/parts/edl-1002 air cleaner on top of it to provide the sealing flange to the hood. The foam ProFlo element I flattened out and cut a hole in the center, then used it as the "seal" to the hood.

I had considered using a Velocity stack as another option, but I didnt have one on hand, and it would be harder to completely seal to the hood.

Anyhow, the cold air by itself made a real difference in the crispness of the engine. It also forced me to back the timing down a few more degrees to avoid Audible pinging. I believe I am now at about 30 total degrees at 8-9boost

The alky spray mechanically functions as intended. I believe it is turning on at about 5boost. I had expected to be able to turn up the boost a bit on the Alky spray without changing the timing. This is not the case. As soon as I add more boost I get pinging, and the Alky seems to not have any effect.

Looking for some pointers from those with experience please.

 

[WarWagon]

I like your cold air idea. I read your using 50/50 water/methanol or washer fluid. Could try 100% methanol or the spray rate needs increased on your 50/50 mix.
Another problem these little carb turbo compressors make a Lot of heat the more you turn the boost up on them. So you have one angle covered pre turbo injection.. perhaps time to add another nozzle for alky in or near the turbo foot and help cool the hot charge out of the compressor.

 

[techg8]

Thanks (I changed over to 100% washer fluid) I may try to find some ethanol or methanol at the hdwr store or the auto store and try that undiluted, see if it helps.

I have also read online (where everything is true and correct) that alcohol sprayed at higher pressures atomizes more, increasing the total surface area of the droplets and aiding in evaporation and increasing total heat absorbtion. Thats one reason why some kits have better pumps than the wiper washer pump I have. But my system was cheap and does seem to have an effect so Ill keep it.

I have tinkered with the timing some more, and the Alcohol definitely has an effect at 10 psi and above.

I have found that my setup can go 8 or 9 lbs at 30 total degrees without audible pinging on 93 pump gas. with or without alky
10 psi - 28 total degrees advance w/alky
11psi - 24 total degrees advance w/alky

It seems to be getting harder and harder to create more boost without pinging at this point. I feel like I am dropping a lot of timing.

It is possible that the stock downpipe and my exhaust is restricting things a little.

Also this is a bone stock turbo.

I was shooting for 12 psi to be honest. Is that a reasonable goal with stock turbo and downpipe?

 

[robzombie]

I'm no H/O guy for sure but I will chime in on the alky setup you're using. Get rid of that low pressure pump and windshield washer fluid.

I tried something similar on a different vehicle when I was clueless and tried to do it on the cheap.

You will not get the atomization needed with that system or the control of a true alky system. Trust me I'm old school and I fabricate whenever I can, but some things you just have to bite the bullet on and a proper alky system is one of them.

Your problems are compounded by the system you are using not helping you. I have a true cold air induction and I have to turn the alky down when the temps are low outside [in the 60's]. Colder air means more power and less heat. The alky volume needed at 60* is totally different than what's needed at 90*. Now that you are pulling in fresh air, not under hood hot air you should be able to run more boost/timing all else being equal.

Washer fluid/water versus straight meth is crap on these cars. What happens to water when it boils/flashes at high temps?? It turns to steam that's what happens. Steam will do a great job of cleaning your intake and valves but it will also do a great job of raising your compression ratio also if you are getting it to evaporate in the manifold as it hits the combustion chamber.

The other caveat is if it doesn't evaporate at all or doesn't atomize which is what I'm guessing is happening in your situation due to the low pressure pump you're using it could reduce your octane because you are adding a liquid with low/no octane value and if injected in great enough quantity could mimic hydro lock on a small scale causing the engine to ping also.

You're heading in the right direction, just using the wrong system.

I use straight water in my diesel only and use a high pressure pump and dual nozzle setup that comes on at two different boost levels [9/16] and will agree that it will lower intake temps as I see a 400* drop in EGTs, but I believe it only gives me more power because it is raising my compression a couple points while also cooling the intake charge.

 

[techg8]

Thanks for your thoughts on it. I will be playing around with my homebrewed alky setup, trying to quantify its effectiveness, and will post the results here as I gather them. I am certain it wont be as good as a system designed to do what I need.

On another note, I modified the distributor to limit the mechanical advance to 10 degrees. When it was at 20 mechanical, I had to dial the initial timing too far back to be able to run 11 lbs boost. This made for a bad idle and crappy throttle response.

I pulled the shaft out of the distributor and used some JBweld to make the oblong advance slot smaller.

I reinstalled the shaft and the distributor, set my timing to 16 initial and went for a drive.

I have great idle and vacuum at idle now. Throttle response is crisp, and the turbo spools up rapidly, all the way to 11lbs with no pinging.

I have 16 initial, 10 mechanical and I am running 16 degrees on ported vacuum

 

[MNcarbturbo]

The reason I dont get concerned with a low pressure large droplet alky mix is that turbo is spinning tens of thousands of RPM and I dont see how it cant chop and water particles up. Post turbo, definitely, but pre turbo and pre carb im skeptical. The bigger problem is the fuel shearing out of the air as tested by AJ from the foot. Anything you do pre turbo is either going to mixed great or get sheared out of suspension from the 90 degree turbo foot.

I dont see 12 PSI being a problem with the turbo, I think the downpipe is the problem. I have a 2.5" DP and ported heads and a cam. Its wastegated to 8PSI. It stays there until maybe 4000RPM and the wategate gives up. Usually 1-2 shift and especially 2-3 shift im seeing 14-15 PSI.

What ive noticed is changing from cast to tubular manifolds made the car spool up a lot earlier. Im in 4-5PSI with no troubles just passing someone or accelerating/merging.

I dont see how your having so much trouble with detonation. Granted its problably timing. I have the BTM, some good heads and a great exhaust system. The only thing holding me back is the intake and turbo foot. (and at 10PSI and even 1 degree im pulling 10 deg of timing out.) I havnt screwed around with timing at all.

If I didnt have my firebird id be a lot farther with research on the drawthroughs but my attention span is too short and the car is so good right now (besides slow) that i almost dont dare change anything.

 

[mikemcvaney]

gather , I modified the distributor to limit the mechanical advance to 10 degrees. . I pulled the shaft out of the distributor and used some JBweld to make the oblong advance slot smaller.

I reinstalled the shaft and the distributor, set my timing to 16 initial and went for a drive.

I have great idle and vacuum at idle now. Throttle response is crisp, and the turbo spools up rapidly, all the way to 11lbs with no pinging.

I have 16 initial, 10 mechanical and I am running 16 degrees on ported vacuum

View attachment 223994

Waiting for some one else to do that, I diid the same thing buy a diferant way works great cost about a penny and took one lunch break. Took my dizzy to get it curved he made it reallt dificult and pricey so I just did it my self works great

 

[mikemcvaney]

What ive noticed is changing from cast to tubular manifolds made the car spool up a lot earlier. Im in 4-5PSI with no troubles just passing someone or accelerating/merging.

Are you sure everyone else on here will argue about the manifolds are much better look at them iron turds
]

 

[charlief1]

The pinging is mostly from lack of fuel. At this point you need some way to see what the exhaust temps are. When you open the under hood area to more and cooler air the air/fuel mixture leans out and need to be richer. Pull your plugs and you see very white plugs. Change the hangers and needles for the secondaries to make it richer.

 

[MNcarbturbo]

Im running stock metering rods and a 76 455 Olds qjet secondary hanger, they are a little richer than factory.

 

[techg8]

Thanks for your replies. Its great to hear from others who run these engines, your input is appreciated.

I am running a 1978 engine with the early exhaust ports. The 79+ manifolds/headers wont fit unless I am mistaken.

Without a BTM or some such device I am relegated to trial and error tuning the timing. I want as much timing as I can put in there - as quick as I can get it in there - without audible pinging or being in the mechanical advance at idle. And I am new to tuning a turbo engine so I probably run into a bit more difficulty, as I learn.

I have been running DA secondary rods - they have a similar profile to the original CP rods in that they get rich quickly, but they have a much smaller power tip for WOT.

I recently went up a size on the primary jets and it had a BIG positive effect on 0-5psi power.

An AirFuel meter and a knock gage would be welcome additions and very valuable feedback, but the money just isnt there so I will have to go without.

Thanks for the suggestion about pulling the plugs. I will start doing that as a way to get some idea where the fuel is at.

It runs so well now that I am hesitating messing with it any more. But I will probably twist some more boost in there and see how it does. Will advise...

 

[techg8]

Q: What is the max boost you would recommend running on a relatively stock engine? How far should I try to push this thing?

 

[b4black]

I haven't got a chance to read this all, but two things to consider. You are squirting pre-carb. I did this as well - I figured the water/alcohol would get fully atomized by going through the carb venturi. Try to avoid too much water/alcohol - you don't want it condensing again on the carb plenum (which is why the plenum is heated by coolant). Liquid drops will damage the turbine.

Water absorbs heat when it evaporates. "Atomized" water is still liquid, just very small drops. It doesn't evaporate until after it goes through the turbo and that's where it lowers the charge temps. Alcohol also absorbs heat and it is also a fuel. It will make your Air/Fuel Ratio very rich, which suppresses knock, but you can go too rich.


E85 is a cheap source of alcohol. Mix it with water and the gasoline will separate and float out.

 

[techg8]

Well I tried to up the boost to 12 psi and couldnt get it to quit knocking without dropping more than 4 degrees of timing.

Seems like I have reached a limit for the current setup.

To get more boost in there I will need either a more effective alky system

or maybe a larger downpipe to help the turbo be more efficient and build less heat

So for the time being I have the boost set at 11psi
and the timng at 15degrees initial and 10 mechanical, 16 vacuum

idles, runs and drives great.

 

[MNcarbturbo]

Do you have a flat spot or rough transition when easing into it from cruise to boost?

 

[techg8]

Do you have a flat spot or rough transition when easing into it from cruise to boost?

no actually its pretty smooth now rolling into the throttle like that, but it also depends on the cruise speed. A low cruise will feel "flatter" than starting from a higher rpm/speed cruise. but theres no "flat spot" like when you press the gas and nothing happens if thats what you mean.

I do have a hesitation when flooring it from a stop but I think that can be fixed by playing with the secondary open rate.

The engine lacks "power" down low, til the boost comes in for sure.
I get 5 or 6 psi on the primaries
It hits pretty hard when the secondaries open and it shoots right up to 11psi

 

[techg8]

Anyone interested in this complete setup? I pulled it out of the Cutlass and am selling it all.

Car (roller), engine, extras. I have several of the turbo control centers, a couple of the red air intake setups, extra manifolds, crossover and up pipes, an extra turbo (disassembled).......

I need to generate some cash and unfortunately my toys have to go.....grrrrrr