ScreaminRedZ

iTrader: (3)

I installed my bottle heater and ordered up some more fuel jets and then hit up the dyno today to dry and get the nitrous dialed in.

Basic mods: Trickflow 215's, 230/236 .583/.583 (with 1.8 rockers) 112 cam, most of the bolt-ons, 12-bolt w/4.10's and spool.

I tried dialing in the nitrous, via fuel jet changes. The blue line is the 100 shot and the red line is the 150 shot.



The blue line is with a .052 nitrous jet and a .040 fuel jet. The red line is with a .062 nitrous jet and a .044 fuel jet. As you can see from the air/fuel, I can't seem to get it right. These were both running a much richer fuel jet than the kit recommends, but it still went lean and then went rich up top.

I have a ticket open with HSW. Not sure if it's a problem with the solenoid or something else.

Opinions?

JoeyGC5

iTrader: (24)

Timing at? You pulling fuel off the rail also?

shortdog

iTrader: (1)

Your fuel jetting is extremely rich. Do you have a window switch? By looking at the graph, it looks like it started off n/a, then the nitrous kicked on at 3500 rpms. It most likely got richer from the bottle psi dropping, in addition to your super rich jetting. You're still making good power even with it being so rich is what boggles me.

ScreaminRedZ

iTrader: (3)

Not sure what the timing is at. The car was tuned by Race Proven Motorsports for a 150 shot, but they couldn't get the air fuel right with the jets I had. I ordered some new jets and went to a dyno up here today.

I am pulling the fuel from the rail.

The jetting is crazy rich. The kit recommends a .028 fuel for 55 psi fuel pressure. I can't remember where the fuel pressure is with the Racetronix pump, but I think it was in the 50-52 range. I started with a .033 fuel jet and it was in the high 13's in the mid range, but not too bad up top. I think it made 530 rwhp up top with 550 rwhp at the spike (around 5200 rpm) and 570 rwtq on that jetting. We kept upping the fuel jet and ended up with the .040 jet, which still didn't richen it enough in the middle, but went too rich up top. Something other than jetting is up.

I do have a window switch set to come on at 3400 rpm.

The bottle was filled before any runs and was set to 950 psi before every run. At the end of each run it had dropped to about 900 psi. Might make a bit of a difference, but I wouldn't think it would cause the air/fuel to drop so drastically.

Thanks for any input!

camscam02

iTrader: (21)

There is something going on because it is peaking really early and then falling on its face. A dirastic drop. the dyno numbers are kinda fibbing to you I guess. Falling on its face because it is going dead rich from 5500 on. Not bad before though.

Id like to see what it is doing around 5200-5400, that seems to be where your problem is. It is DEAD rich! That fuel jet is way too big.

Im not sure what is going on at the moment. but ill think about it.

ScreaminRedZ

iTrader: (3)

Yeah, the rich problem up top is due to the too big fuel jets I think. I'm trying to figure out why i can't get it to richen up in the mid range there. Maybe a fuel solenoid sticking or something and then opening up at the top of the pull?

We did a bunch of pulls and every one looked exactly the same, with the richer fuel jets slowly bringing the air fuel down. We stopped here since it was going way too righ up top. With the .033-034 fuel jet it looked decent at the top of the pull, but the air/fuel was in the high 13's in the mid range.

Thanks!

WE TODD DID

iTrader: (2)

Does the timing on the engine change through the rpm?

dnkynrbk

iTrader: (34)

Sounds like either you have a bad ground,wiring or your fuel pump is not holding up. We saw this on a car we were tunning where na its was fine but when you sprayed it. It would go fat then lean then fat. Do you have a aftermarket fuel pump like a walbro 255?

ScreaminRedZ

iTrader: (3)

Yeah, the pump is a Racetronix.

Not sure on the timing, I'll have to call RPM and ask how they set it up.

If I end up having to through darts then I'll probably start with upgraded solenoids (the kit that HSW sells now has bigger ones than my kit came with) and a fuel pressure gauge.

dnkynrbk

iTrader: (34)

I would check the wiring, I know on my kit I had to rewire and you 12 gauge and 10 gauge for the grounds. Before I used 14 gauge and it would pulsate going down the track. I would also make sure you are you are using a good ground thats clean. If that checks out then would have to be the fuel tables.

dnkynrbk

iTrader: (34)

I would also check you alternator if its the orginal and you dont think its making peak voltage under max power it will cause your noids to almost pulsate and loose power when there is a heavy voltage load. I have seen this happen while tunning cars to. We had a problem with a car that sounds similar to yours We put a new battery in a car and alt. and it worked fine. I hope this helps you. I dont think its your noids or you would be losing total power.

ScreaminRedZ

iTrader: (3)

I'll contact RPM and find out if there was any new wiring involved with the pump install and then check and grounds.

I'll also check the alternator. The car has 33K on it and the alternator is new. I just put a new battery in it, so that end should be covered.

Thanks for the advice!

dnkynrbk

iTrader: (34)

Your welcome. Man I will try to ask some friends around here.

ScreaminRedZ

iTrader: (3)

Thanks! I also shot Fran at RPM a message asking about the timing and the pump wiring.

From these preliminary tests it looks like I'm gonna get some very nice gains once I get the bugs worked out.

itsslow98

iTrader: (18)

I had jetting problems with my HSW kit as well. Started with the recommended jetting .028 and ended up with a .033 for a 100 shot on a basically stock car. I made a thread as well. Now i have to go through it all again because I got a NANO system and i know it wont be easy. Also tuned at Race Proven.

camscam02

iTrader: (21)

Might be a coincidence? same shop, same tuner, same wideband. interesting.

WE TODD DID

iTrader: (2)

Now that I looked at your dyno chart again, it looks like you hit the nitrous at 3500rpm. It never went "lean" while the nitrous was activated, judging from your graph. Correct me if I'm looking at it wrong.

camscam02

iTrader: (21)

He stated when he tried the recommended jetting .062 .034 it would be high 13's when activated and the come down to a good afr in the upper rpm range. They didnt like the high 13's at the hit/midrange so they put a big fuel jet to fix that but now it is in the 10's afr in the high rpms.

Atleast that is how I read it.

itsslow98

iTrader: (18)

I just got a wideband with datalogging capabilites and the car is going on a local dyno so I'll let you know if there is any significant difference.

ScreaminRedZ

iTrader: (3)

This problem seems to have occured since the car was tuned. When we had it on RPM's dyno I didn't have anough jetting to play with it. With a .034 fuel jet for the 100 shot it was starting out in the low 12's and then dropping into the low 11's. I was trying to lean it out a bit so this time (different dyno) I used the .033 jet, but now it's going lean and then was ok up top. With the same jetting that we used at RPM, the air fuel is now different.

Same with the 150 shot. At RPM the .062/.044 jetting for the 150 was in the 10's right off the bat, with the meter being pegged below 10:1 at the top end. As you can see here, the same jetting is now in the low 13's until over 5500 rpm where it drops down into the low 11's.

On motor the air/fuel was reading the same on both dynos.

I'm looking to get the air/fuel between 12.0:1 and 12.5:1.

If you look at the blue line on the graph (100 shot with .040 fuel jet) the nitrous comes on at 3500 rpm. The air/fuel starts around 12.0:1. Around 4200-4400 rpm it gets into the low 13's. It then drops to around 12.0:1 at about 5100 rpm before diving into the 10's over 6000 rpm. With this jetting it should be rich the whole way. If we went leaner then the air/fuel was too lean in the middle (already too lean at 13:1) but it was better up top. If we went richer then it was going to nose dive even more up top.

The red line on the graph is the 150 shot with .044 fuel jet. This should produce a leaner ratio since there is less fuel in relation to nitrous, which it does, but it's still rich up top. For this one it comes on at 3500 rpm, but this time it's already in the mid to high 12's. Over 4000 it's in to the low 13's (leaner than the blue line even) and then starts dropping around 5300 rpm, dropping into the low 11's up top.

Exactly!