Ok my tune is a little richer than I would like it at low rpm, part throttle. I know very little about tuning. Virtually nothing except for what I read on this board. My engine management is haltech.

First, if anyone can post a screen capture of their target fuel map from a VF tune with load/rpm I would be curious to look at it.

Second, I have a low boost kit. It is a roots blower so I can get full boost anywhere, but it maxes out a 6-7 psi depending on conditions. I also have a new TVS blower that runs fairly cool and an oversized intercooler. It should not be very high intake temps. On a hot day, when the sensor is heat soaked, it will read 139 degrees if you let it sit and idle, but the temp drops fairly quickly from there when you start moving, even under boost.

Even with a low boost, aftercooled kit, on 93 octane, my tuner had it running fairly rich in part throttle, low rpm conditions. So I did a little experiment and looked at the tune. First off the injector flow rate was set at 710 when they are 725's, so I changed that and it helped a tiny bit. The target fuel for load conditions below 5000 rpm, was in the 11.4-11.8 range, and here I might be seeing 1-2 pounds of boost if I was driving lazily, and the car might spike into the 10's at times.

I changed the target fuel in all cells in the "engine load" 2500-5000 range to be 11.8 at the richest, and as lean as 12.2 afr, and this has helped a great deal. It seems like it could be helped a little more but I don't want to go too far. Tuner is 80 miles away and booked two months out.

So I guess I am curious what people think the target should be for this range or the tach when I would be seeing 6 pounds of intercooled boost at the most, and most of the time just 1-3 psi unless I am flooring it.

And if someone can help me understand, the farther I get away from 0 on the load scale, I guess towards higher load, what does this represent? Higher drag on the car from weight or a hill? Lower throttle opening? I just want to understand if I tweak it a little where it should be richer and where leaner is safe. The farther I get from 0 (and the scale goes up to 83 kp something or other) is this more throttle, harder acceleration or something different?

Thanks

 

Nobody with VE tune experience? Bueller? Bueller?.....Bueller?

 

pm sent.

 

I couldn’t tell you how your load setting are calibrated in relation to throttle opening and boost, but generally anything under boost should be in the low to mid 13's at any load point and stoich range at idle and light load. When you start to see small amounts of boost, that when you should get into the enrichment duty. I always aimed for about mid 12's at low boost/lower rpm and by vtec range and moderate to full boost then calibrated for upper 11's to 12. Sounds like your running really too rich in the first half of your load points at least.

 

Ok that helps. I will tinker a little more and maybe post a capture of the table. It was weird in that in the load ranges, it would be 11.8's in low rpm, then an island of 11.4's in the 3700-5000 range and then back down to 11.8's for high rpm. I did not understand what the island was for unless he was hearing some kind of knock, but the car seems to choke on the richness rolling into throttle. I changed the "island" targets from 11.4 to 11.6 and that even seemed to help a lot and make the car respond much more smoothly and not boggy. I'd like to take it a step leaner to smooth it out even more but wanted some input as to how far to push. I don't know what the load factors mean, but it starts at zero and the load part of the table goes to 83 kp something or other, in increments of 15 or so at a time.

 

Yeah you will no doubt benefit from leaning a fair bit in these questionable areas, unfortunately I never tune off of your load factors either, so I dont know how that translates to the areas of the curve i understand. You may have to spend a little time looking at your data logs to see the relationship between your throttle position, vac/boost amount and where in those tables the fuel cells are tied into, then drive the car and start deducting. From the sounds of it, most of the fuel corrections you want to change are in vac to 1-2psi, all the transient throttle response, which is the most time consuming and yet important area of the curve to tune for the best running car. So figure out where those group of load cells are and then draw the lines to the fuel cells as mentioned. If you can do this wile your driving and have a wideband for instant a/f visual on correction confirmation, that will help a bunch. Good luck!

 

Hey man, honestly, based on the simple questions you're asking, you should definitely take it to someone for tuning. We all want to start tinkering with little settings here and there to save money on "minor" adjustments but before you know it, boom, something bad happened.

The higher the load past 0" vac, the more boost/psi its seeing. For me I aim for low 12's from 1-4 psi and then richening up to mid 11's AF at full boost. VE works in mysterious ways. Technically, once you tune the VE tables, you shouldn't have to touch it again unless your motor loses efficiency somehow or you mod it.

 

Points taken.

Can someone give me a basic understanding on what the load factor is representing as it gets farther from vaccuum? Is it throttle? Is it boost? is it a combination?

In a roots kit throttle and boost should be tied together maybe a little more than others because you can get close to full boost at all rpm. A novi might only get to full boost at 9000 rpm, where I can induce full boost at low rpms but only if I am WOT. Part throttle gets part boost.

At say 4000 rpm, I can have 0 boost, 2 psi, or a full 6 psi depending on how far down my foot is.

 

load = manifold pressure

 

not directly related and also matters on how your tune is created relating to throttle position. low rpm half throttle can be more load then half throttle at higher rpm.

to tweak your tune you need to just know at what rpm and what load you are seeing to much or to little fuel.