Well I went to the dyno yesterday. Just put a JRSC on my 98 SH, with AEM SR and VAFC. I'll explain what happened. I got strapped down and did my first run. I peaked at 188whp. This is fine, but he said I was running lean (14-15:1) Little too high. Anyway, I then adjusted my VAFC up 15%, it was his suggestion. When I did that, my ratio got better (13-13.5:1), but my power took a HUGE dive. I think it got down below 50hp at some points. We then backed off the fuel and watched the ratio go back up along with the power. We adjusted the vtec point down (had it set to 4800) and adjusted the timing, which ended up hurting again. I know my belt was slipping and that also contributed to my lack of peak power #'s, but the air/fuel #'s are bad. I ended up just making a nice smooth power curve, but still running over 13.5:1. I do have my stock cat and exhaust and he said that probably accounts for about .5 of the air. Does anyone know what could be wrong with my air/fuel mixture problem? One thing I didn't do was adjust the JR FPR. Do I need to do this first to get a better ratio and then mess with the VAFC? Would this explain the backwords reaction I am getting from the better ratio resulting in lower power? Thanks.
No I'm sorry, I'm talking about my SC drive belt. It squeels like crazy over 6000rpms. Do I need to just crank the belt as tight as I can? I don't want to overtighten, unless this isn't possible.
I think for my A/F issue I need to adjust my JR FPR and see what that does. This may be dumb but do you do this adjustment while the car is running? Thanks.
I do understand that. There seems to be some question about the VAFC being able to increase or decrease fuel or both. When I increased, I definately saw a difference. The difference didn't make sense (better ratio with less power), but it definately did something. I'm gonna go adjust the FMU and see if it helps. Obviously I won't know for sure until I get to the dyno next.
No I'm sorry, I'm talking about my SC drive belt. It squeels like crazy over 6000rpms. Do I need to just crank the belt as tight as I can? I don't want to overtighten, unless this isn't possible.
I think for my A/F issue I need to adjust my JR FPR and see what that does. This may be dumb but do you do this adjustment while the car is running? Thanks.
I'd get the tension specs from JR and tighten the belt per their instructions... but obviously, if you're belt is slipping, that's all lost power.
I do understand that. There seems to be some question about the VAFC being able to increase or decrease fuel or both. When I increased, I definately saw a difference. The difference didn't make sense (better ratio with less power), but it definately did something. I'm gonna go adjust the FMU and see if it helps. Obviously I won't know for sure until I get to the dyno next.
AFAIK, you can only subtract fuel with the VAFC, not add fuel.
__________________ Medium Scott - XBox GT: derech0 - 2005 PPW Track Model: 58k Miles
No I'm sorry, I'm talking about my SC drive belt. It squeels like crazy over 6000rpms. Do I need to just crank the belt as tight as I can? I don't want to overtighten, unless this isn't possible.
You need to get that fixed first. You need to tune the car with the supercharger kit working properly. In the instructions, it should mention how much to torque the bolts to.
Quote:
Originally Posted by luder621
I think for my A/F issue I need to adjust my JR FPR and see what that does. This may be dumb but do you do this adjustment while the car is running? Thanks.
I think the idea is to get it to a certain static fuel pressure at idle and tune from there. I think you need to do some research on the threads in this forum before you proceed.
__________________ Medium Scott - XBox GT: derech0 - 2005 PPW Track Model: 58k Miles
V-AFC modifies the MAP setting. So when you set it over the max (100% vacuum) it doesn't work. Which is why you just have to up the pressure with the JRSC FMU and then fine tune with with the V-AFC.
When i tuned with my VAFC to correct fuel, i only used it to subtract fuel. I also have a few different components than the stock JRSC Kit but if you can make it as rich as possible, then you can use the VAFC to lean it out. Theres no way its gonna help when you try to add fuel.
Well on Friday I turned up my FMU as far as it will go (all the way in). I don't have a fuel pressure gauge and I'm gonna have to get one, but by turning up the FMU, I'm still running between stoich and rich most of the time (as indicated by my autometer a/f gauge. I heard we should be running way rich with this kit. There is pretty much nothing else I can do to turn up the fuel, I'll just have to check my fuel pressure. Before the FMU was adjusted, my gauge was mostly stoich. It seemed to only turn up the fuel pressure a little bit. Is it possible to have the FMU backwards? If so what would this do to my fuel pressure? Thanks.
if you have the JR FMU, you are only adjusting the static FP, meaning when your boost gauge reads 0. under normal cruising there will be no changes, you will see the effects of your adjustments when you transition from vacuum to boost.
btw... dont trust your a/f gauge unless its a wideband
Yeah I understand that, I meant my A/F readings were what I was getting at WOT under boost, still between stoich and rich. I'll have to get my fuel pressure gauge in there to really know what goin on.
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