We mapped mine to a 0,86-0,88 lamda on 99% TPS and 5hg.

With a Alu-heads. 10.7 compression, 0.38 quench. 35 deg timing.

What should make most power. I tried 0.84 but lost power, tried 0,90 and lost alot.

Can i use more/less fuel when using 38 deg timing?

Can i use more/less fuel when stepping up in Header size?

What do you other guys run?

10-12% rich at WOT is right for max power. Since you have EFI you only need that at WOT. Below about 85% you should map it to 1.0λ.

I have been doing a lot of work with mine. I use the afr side though. I have found my car likes the 12.5 to 12.8 range. It has been making the most power there. (according to the g-tech which I use with it to measure HP) I have been working with a few other cars as well. My friends car (which is a milder combo than mine) likes 13.0 to 13.2 range. (we have not taken the car to the track to find his timing sweet spot) I have another friend with pro comp off road truck. His set up seems to favor the 13.2 to 13.5 range. Now his results have been determined by the seat of your pants feel test. He says the truck just runs harder between 13.2 and 13.5. Most people I talk to say most cars will make max hp from 12.8 to 13.2. How are you doing your tests? Is it driving or WOT runs. I have found a huge difference between the to. I have a lot of hours invested in this and I am finding for me that it is best to tune for WOT. I have also found a difference in readings from a stop to 1/4 mile run, first gear at 3000 rpm then hit WOT run, and also 3rd gear WOT runs. I have not tried messing with the timing. My car makes the most power at 42deg so I have left it there. Since timing effects the fuel curve I would suggest finding your timing sweet spot (max HP) and then tune it from there. This has been the best tool I have ever bought. For example would anyone have thought that a pump gas small block would have a lean condition at WOT off the line with 2 double pumpers?? I never would have. I was spiking to 20 to 1 for almost .5 of a second with the stock 28 squirters. I have now gone to "2" 35's in both carbs and I am at 14 to 1 off the line. The car pulls like a monster out of the hole now. I also found that I has uncovering my pick up tube when the gas was below 1/2 a tank. I have also been working with power valves in and out. So far I have made the best curve with the power valves in but the car is to lean at cruise. I am thinking about adding some .008 wire to the power valve channel restrictions so I can go up in jet size yet keep the curve but fatten up the cruise. Has anyone done this??? Monte

I mapped it on the dyno. But the time went away when i broke my rotor... ;(

So i only dynoed @35deg.

My engine guy said i can come back and dyno it on the wheels later. When installed it in my car.

I got a little less HP than expected. So i start wondering about this.

Are you sure about the 5 inches? Or is that a typo?

hey monte what sensor/ guage do you have. i was looking at this unit from inovative technologies that is a small data collection unit itll record like 60 sedonds of A/F data and they you can down load the data and view it on the computer. you could map an entire run at the strip and figure out if you leaning out at any point during your run.

It is the Innovate tech unit. I was sold on it after I met the guy who invented it at SEMA. It will record 44 minutes of data. I keep it and my lap top in the car when doing testing. The unit itself stays in the car all the time. It told me more things about my car in the first 4 hours of using it than I could have imagined. It is the best tool I have bought/used yet. Monte

It should be 0hg... I didnt think correct ;)

Any of you or the Dyno guys have an answer to my question in the above post? Thanks Monte

Monte, I bought the LM-1 also. And I agree, it's one of the best tools I've ever bought.

And I've heard of people runing wire through th PV restriction channel for tuning. Sounds funny, but it works.

Any idea what size? Is .008 a good place to start?? Anyone know? Thanks Monte

Where do you get it and how much? I'd like to use one as well.

Troy.

Mike, I would just put the wire in and run it. You've got the meter to check it out. What do you have to lose?

Troy, check out my web page (http://www.geocities.com/compuboy007/) for info on how to get it. It runs around $350.

If the O2 sensor is not the wideband one, then keep in mind that sensor output voltage is a function of air/fuel ratio, exhaust gas temp, and backpressure. The narrowband ones aren't the best tuning tool to use as they are only accurate near stoich (0.5V).

It's a wideband unit.

I believe there is still a group buy going on over at www.thirdgen.org (http://www.thirdgen.org) for the sensors

http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=204651&highlight=group

Later
Steve

I am going to try some .008 wire and use the wide band to track what happens. Has anyone out there done this to the PVCR's? Still looking for someone with experience in this area. Dyno guys, carb builders, anyone??? Thanks Monte

Small world - I ordered one of these also - it arrived today. I just chassis dyno tuned my car and found that it made the most power right around 12.8 and the plugs looked safe also.

I am going to hook up the LM-1 and compare the results to the dyno session - and use it for logging runs on nitrous also.

66, I would like to know how the maps compair. Also I would think they would differ some because one is street and the other dyno. When you get it, check out the lean spike off throttle. I got mine almost flat. It really helped my launch off the line. Monte

Just curious, what was your cure for the off-idle lean condition?

Originally posted by Monte:
66, I would like to know how the maps compair. Also I would think they would differ some because one is street and the other dyno. When you get it, check out the lean spike off throttle. I got mine almost flat. It really helped my launch off the line. Monte Snowed here today so I won't be able to get on the streets for a few days - leaving for memphis in about 9 days.

I'll worry about launching later - I will be using the WOT fogger assisted launch and it doesn't care if there are even jets in the carb LOL.

I'm interested in what A/F you tune for part throttle - I want the car to run cooler while cruising around. It doesn't overheat, just want to run it cooler if I can. I was thinking of adding some timing through toggles (retards on my digital 7) for cruise, then when I go to the track, I can flick the retards back on. Like a po-boy vacuum advance.

I can cruise at a good speed around 2500 RPM and need to tune the idle and intermed air bleeds and fuel restrictions such that it is fatter part throttle without affecting WOT too much.

My custom carb has jetted intermediates in the dominator so that I can change the fuel feed but I'm wondering what I should be aiming for with AFR.

One other thing - are widebands accurate when you are shooting raw fuel past them - when I sprayed the nitrous on the dyno the AFR on their wideband read 9:1 but the plugs were clean - I have so much timing rolled out of it that i'm sure it is burning on the way out (16 deg total) but despite the 9:1 AFR (which I don't believe) it made 4 figures at the rear tires spinning them hard! It was spinning and grabbing so much that it had readings as high as 2100! LOL. Not real, but some of the big numbers were...

Better get back to work - put new clutches in the tranny today and need to get the car back together so I can play with it this weekend and tune before the big race.

Ryan

With a a car like your's I'd tune for around 13:1 at cruise.

What is your jetting and fuel pressure. As you know a lot of jetting is very rich and could end up with an overall 9:1 A/F. I'm no plug reader, but you could still have clean plugs, where was the heat line on the ground strap, etc (IF you were running race gas, pump gas is another story).

I'd want to know what kind of O2 sensor you used on they dyno (Bosch or NTK) and where it was mounted (collector...how far from collector).

I'll try out the LM1 this weekend.

My A/F N/A was perfect - made about 5 pulls to get it right - which is a bit of a waste of time since I'm going from 5560' DA to almost sea level so I'll have to tune the main jets when I get there...

The 9:1 is possible because the timing was soooo late that it was putting raw fuel out the pipes - what is the lowest range that a Bosch can read? I thought it was about 9 or 10 which would make sense. The strap and fuel ring were fine - I could probably take a half a psi out of the nitrous and add 2 deg, but it's safe. (ground strap was halfway to the 90 - went from 16 to 17 deg and it moved about 2mm closer to the bend.)

It was a bosch 4.2 and mounted about 3" behind the collector.

Here's a question - any guesses on jet changes going from 5560' DA to about 1000 feet DA? I'm running 96 jets and 28 high speed bleeds.

Ryan,

Best of luck at the pump gas drags. Give 'em hell. graemlins/thumbsup.gif

I am trying to tune the car so that the afr is fairly even at WOT and cruise. Part of the reason I am going to try to make the PCVR's smaller with wire is to get a more even overall curve. When I get a good WOT (12.8) curve, without power valves, it is to fat to drive. It is usually around the 10.5 to 11.5 area cruising at around 2500 rpm. When I put the power valves back in, I actually get a little smoother more consistent WOT curve. (jumps around less) However the downside is I run around 14.5 to 15.5 sometimes 16.0 cruising at 2500 rpm. Sometimes I can feel I am starting to get into lean surge. I am hoping to put the wire in and be able to go up in jet size to help out the cruise situation but keep my WOT curve at 12.8. I run 600 Hp's and have messed with every possible combination of air bleed as well. Nothing has helped. I wish these carbs had the intermediate circuit like my Dominator. So far the stock Holley bleeds sizes have given the best overall curves. As far as how accurate the wideband is with raw fuel I am not sure. Back when I was running raw fuel out the exhaust, and was running 1600 deg EGT's, I didn't have the wideband. So if anyone has any suggestions on how I can get a better curve (without changing carbs) I am listening. Monte

Ryan,

I believe the rule of thumb is 1 jet size for every 1000 ft. difference in elevation.

Monte, the tripower guy who helped me had done it both ways wire and tapping a lead shot in there and then opening it back up with small index drills. Of my three metering blocks, two were .062-.065s PV channels and one was .055"- .057" - which I used in the primary side.