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raising the rev limit

SgtMarshal

SgtMarshal

Active member
I've been trying to figure out how to raise the rev limit. I have an xp cam and 90 lb springs, and I want to see how the car runs at 6200 instead of 6000 where it is currently set.

One more question, a friend suggested I add 3% more fuel in PE, but my LTFT's are reading -10. adding more fuel when the engine is cutting fuel doesn't make sense to me.
 


Not sure on DHP for raising shif points.

You'd add/subtract fuel via the MAF, not through PE. PE is just a set fuel amount that you want it to at or roughly around.
 
he told me how to do it and I saved the bin with the adjustment for more fuel, but I dont understand why it would help. Before I load the tune, I want to understand the theory behind it.
 
the rev limiters are under the torque manangement tab. there is also a rev limiter under the spark, speed/rev limiter, rpm threshold.

im assuming if this if your first time changing anything that you havent gone WOT with the cam. do you have a wideband? i really dont recommend beating on it to hard without one. anyway. look under the PE tab or post your bin and ill take a look at it. for an xp car i believe most are shooting for 12.2 ish on the commanded PE afr. PE is kind of like a set it and forget it table. if you get the other stuff correct. IE your MAF table, injectors, etc. the car uses the MAF 14.7 "baseline" and it just shoots more fuel on a calculation for the PE. dont beat it until you know what the fueling is doing. dont rely on the narrowbands.

if you havent already read read read the tuning notebook!!!!!
 
You don't add fuel to raise a shift point. You follow what Neb said. Go into the rev limiters and move them up. Then raise your shift points. ensure your file is setup properly to not cut fuel/afr
 
I have read Jerry's tuning notebook, but I dont understand it all. I have a wideband and am working on getting it to function. I have a friend that has done a bit of tuning on it, we ran out of time at the last session and were not able to get the wideband to work. He has tuned a few cars but no 3800's. If you pm me your email I will send you a scan. I went and drove around for about fifteen minutes yesterday and took a scan. I have gone WOT a bunch of times, so hopefully I haven't screwed anything up.

I know you dont add fuel to change the shift point. I am just trying to understand why the suggestion to add 3% more fuel would be given if I was already running rich.
 


You may or may not be running rich. That's what your WB will tell you. You might need to work on tuning further to get the fuel trims to not fluctuate and screw with your desired fueling.

If you walk through the tuning process that Jerry outlines, it'll be a learning experience the whole way. Doing stuff like that helped me get more hands on time and feeling more comfy understanding and working on tunes.
 
At first without someone standing there that has a great understanding taking a ton of time to go through how all the various things can interact.. it's tough to understand immediately w/o background.

That's where all those guides come in. You start following them..and while they might each approach things differently, the desired result is a good running powertrain. A good friend explained something to me about tuning and ...it's pretty universal. There's so many ways to achieve the same end result. Never be unwilling to change or think about things in other ways.
 
SgtMarshal said:
so adding fuel may or may not have much affect?
Click to expand...

have an affect on what? your shift points? no. do the maf tuning as it is lined out in the tuning notebook get your trims down to 0 to -5%. get your wideband working. once it is; if you have your trims locking at 0 in WOT then your WB readout should match whatever is commanded in your PE tables. email me your scan and your .bin file. [email protected]
 
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If your pcm is attempting to maintain 12.0 AFR and it's currently seeing 11, it's removing fuel. If you add more fuel by playing with injector tables etc. it'll simply remove more unless you lower the afr and check other things like Neb said.
 
SgtMarshal said:
I didn't think it made sense to add fuel when the pcm was already subtracting fuel.
Click to expand...

exactly you're on the right track. gotta think about that the scan data is telling you. its possible that you may be pulling fuel from the lower cells in the maf curve and adding to some in the upper maf curve. maybe that is why he mentioned that but at this point its all speculation with out looking at the scan and tune.
 


Marshall... there are a few tools in the stuff you have that would allow you to load your tune and have it determine what you likely need.
 
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