Boost vs timing on pump gas

[venetrex]

I am trying to figure out which is the better way to tune my car for more power, before I go to the dyno or track. I have an arc2 and an emanage blue for tuning, a wideband, and a mmcd datalogger. I also have 550cc injectors. More mod's in my sig. My question is right now I have a 17.6 psi peak and hold 16.8 psi to redline in third gear. No knock. I had to pull timing in the 4000-5500rpm range to queell knock even at 10psi. however now that I have a no knock tune I have been able to slowly ease up the boost (which is no easy task with the eo1) with a combo of rpm offsets and gain and start settings, uggh. Anyways what I want to know is how high can I crank it? And at which point is pulling timing to add boost unbenificial. I dont every want to buy race gas, just way to expensive and being this is a street car I want a pump gas tune. My fuel map I could take a picture and post as well as my ignition map. I also have realized that the knock really only occurs in the 4500-5500 rpm range. I originally pulled it from 4500- redline, but have realized I can start putting some back from 5600-7200rpm. Anyone know why this is? I also noticed with the addition of cam gears at a +1 -3 that my upper rpm boost it easier to control, much flatter boost curve, however I dont get max boost in 3rd until 3700rpm 16.8. Is that normal with dr650r's? Anyways sorry for the long write but I have my car running better now than in the last 3 years and want to get in better. Thanks

[venetrex]

Anyone on this????

[Kibwe Walker]

The most I have seen people run on pure pump is 18-19 psi with 93 octane, 16 with 91 octane.

I am going to play with that scenario myself when I get the wideband on. Tuning with the neo and ITC. Pulling the timing seems to yank the balls away from the car though. I could probably run 20 psi with enough timing pulled but it wouldn't be very fast.

[cbehnken]

see if you can find mellon's old threads. AFAIK he ran 20 PSI on pump with DR650s and timing pulled.

[lawdogg]

I don't really have much to contribute except to make sure you've seen Trevor's thread loosely related to this subject:

Tech: My take on injectors vs. timing control vs. HP with the stock ECU

I know you have emanage blue etc but still, worth a look.

[venetrex]

According to Trevor's chart I am pretty close to where I want to be with 550cc injectors. I was getting knock at the 4500-5500rpm band. I originally pulled timing from 4500-7000 but then realized on the upper rpm range I don't need to pull timing. Been slowly putting it back in. I believe I'm slightly rich, 10.8-11.1 a/f, going to get a target of 11.5 a/f except in the potential knock zone. Gotta love the profec for tuning . Record my a/f vs rpm vs boost, play it back, find where I am rich/lean, back out to the emanage and the fuel cell is highlighted, I just discovered this 2 days ago. That is just plain awsome. On another note does it make sense to add timing for better spool from 1500rpm-3500rpm??? I was thinking about playing with this.

[mehlosTT]

Originally Posted by venetrex

According to Trevor's chart I am pretty close to where I want to be with 550cc injectors. I was getting knock at the 4500-5500rpm band. I originally pulled timing from 4500-7000 but then realized on the upper rpm range I don't need to pull timing. Been slowly putting it back in. I believe I'm slightly rich, 10.8-11.1 a/f, going to get a target of 11.5 a/f except in the potential knock zone. Gotta love the profec for tuning . Record my a/f vs rpm vs boost, play it back, find where I am rich/lean, back out to the emanage and the fuel cell is highlighted, I just discovered this 2 days ago. That is just plain awsome.

On another note does it make sense to add timing for better spool from 1500rpm-3500rpm??? I was thinking about playing with this.

Nope, adding timing there won't quicken spool up because what you want is more_ heat and not less. More timing lowers the heat. The car isn't making any boost at below 3000 ish rpm so adding timing between 1500 to 2500 rpms just helps throttle rol on ( to a point) What you want is more heat generated at 3000 rpms through 4000 rpms and then only between about 2psi and 8 psi load rows. Lower timing a few degrees in this area. It will help spool-up as the extra exhaust heat comes on.

[keithmac]

I`ve found pulling more than 3 degrees timing with 450`s in there makes the car slower, 6 degrees pulled kills it. since you have 550`s you`ll have to feel around for a sweet spot, no point running 20+ psi when the timing`s too low to take advantage.

If you over-do pulling the timing the car will feel flat and you`ll lose power.

I went with a methanol setup because of knock, and how flat the car felt when the ignition was pulled enough to controll it. I gained 6 degrees of timing by running 1.2lmin of methanol and you can really tell the difference.

[Erick]

max boost in 3rd gear from a roll at 3700 is about what I get too.

93 octane isnt in my immediate area and have found myself working on getting the most out of the 91octane in the tank lately. I am spraying meth/water & have timing control. Ive been able to run a good a/f and tune it for no knock on DR650s at up to 20psi with 720's. (when the car is not yet heatsoaked) pulling a good chunk of timing at 5500rpm area.