well went to the dyno yesterday and had an issue with a lean spike that just needing some info that i couldnt really find with the search button. The car is a cam only (vindicator cam) car with a 9in, full exhaust and spraying a 125 wett shot . I have a racetronix pump with the hotwire kit and stock injectors with stock fuel rails. It made 545rwhp and 605rwtq on the dyno but the lean spike hit 13.7 and slowly came down to 11.8 by the time it hit 6 grand . you can tell it just sucked the line dry at the initial hit at 4k but the pump finally caught up but still not till 6 grand it didnt get to 11.9 range. we changed to a higher fuel jett and it didnt help. my question is am i looking at needing a stand alone or is there something else that might help this problem.

 

What your describing dosen't sound like a 'lean spike'. It sounds more like a flat out lack of fuel supply.
A stand alone would take care of that, or you could continue to upgrade your fuel system.

 

Lean spikes usually last less then a second or so, as vinny said, this is something else. I would bet that a standalone would most certainly solve all your issues. If the problem was with your fuel pump itself, i wouldnt expect it to correct itself in the upper RPM. I would only expect to see it get more lean. Most likely its your rails or you would need to upgrade your fuel system to a return style with a regulator at the rail. Again, i think the standalone would be your best bet though.

 

thanks for the info. i have one more thing to throw in the mix that i have a ? about. while on the dyno we had to put the car on a jump box becouse the bottle heater was killing my battery during the between runs. would that effect the pump if the battery was completly charged back up from the hard startup and it got better in higher rpms becouse of that? i was looking at your stand alone that replaces the fuse box for 599. Is that everything you would need?and what is all involved it running a return stlye setup.

 

Thats interesting, its a possiblity that you werent getting enough voltage to the pump. I dont think its likely, but its impossible for me to say yes with any kind of certainty. The return style, is exactly how it sounds. Typically consist of an aeromtive regulator mounted at the rail with a return line to the back. I believe there is a good "how to" on the site, just try a search.

Yes our standalone includes everything you will need to drop it in and go.

 

I just noticed you had that same standalone kit on sale for christmas? I will prob call you soon to order it.let me know if you have a new sale before then if you dont mind... anybody have any other opinions on this matter? This is the first time the car has done this but def isnt a tune issue or jetting.

 

Voltage will effect fuel delivery 100% of the time.

We used 1 of the casper voltage devices on a car with good results. it boost altinator voltage output to 14.5 above 40% throttle.

But like mike said a lean spike is normallt for 300 rpm or so. not 3000. thats a lack of fuel which could be from the low voltage. what did the fuel look like on the motor?

 

Looked perfect on motor but my battery wasnt almost dead from the bottle heater on those runs. It just seems funny that the higher rpms i spun the more the pump fixed the a/f and seemed better. it was lkike a gradual decline in a/f after the inital hit. which had me thinking about if i had enough voltage. would that casper kit work good with the hotwire for the pump becouse the pump is coming directly off the alternator. where do you purchase these.

 

One would think that your alternator would be providing plenty of voltage to your pump?

 

Yes all the casper thing does is instead of the alt putting out 12V it bumps it to 14.5 or max output but it runs off the wot switch so it only does it at 1/2 throttle or so or more. worked great with the hotwire kit.

 

how much is the casper thing and how hard to hook up?

 

I have some people telling me it might be my filter and fuel rails prob just need to upgraded. LOL i really dont know which way to go .

 

+1 for low voltage being the issue.

 

We have been to 720 rwhp on stock rails/filter with a hv255,casper and hot wire.

 

The racetronix system should have no problem support 650 hp. You deffintly have a fueling issue. If the battery was dead you need to start your tunning process all over. If the problem is still there check the fuel filter.

I would put a fuel gauge on the car..
Dave

 

well went back after replacing the fuel filter ,battery and checking all the wiring for the pump and nitrous kit. Idles at 64 and cruises 63-64 so i know the hotwire kit is working . Did fine on motor but on spray once again fuel pressure dropped to 45-50 on the hit and went lean to 13.8 then down to 11.8 by 6100 rpms Funny thing is the a/f dropped almost the same as my tq did but the hp stayed straight across. It did 555rwhp and 605rwtq but this is going through a 9in rear with a chromeoly ds and on 315s.

 

Just seems like it is just sucking the line dry on the hit and it is trying to recover . I have a fuel guage at the fuel rail and i have one in my pillar pod. I guess a stand alone at this point is my only choice or a return style system. I know i need injectors on motor they were 95% . Just done see why i have to have one with this small of a hit

 

As said above the racetronics kit should be plenty for your setup. I would double check your pump in the tank. You may have a fuel leak and not know it because it is leaking in the tank.

 

I have a racetronics with a hotwire kit . Mine would drop 10-12 psi on a 100 shot.(about 550hp)
I now use a HSW standalone

 

I would suspect your pressure drop is just an inherent evil with the rear mounted regulator on these cars. You can do as Mike above suggested with moving the regulator up front or do a stand alone. Regardless, I would gain access to the pump assembly and inspect/replace the regulator inside the assembly.

Nick