Well Im doing something wrong hehe.

So far these are the mods ....

Ported the front of the plenum
MSD digital 6 box with 6* retard on the spray
MSD coil
Accel 10.8 wires
Hooker long tubes
Hooker 3" front Y
Gutted cat
TPIS 3" rear Y
Flowmaster 50 serires
Cut the air box lid
Accel Kool blue fiter
Air pump delete kit
BBK afpr set at 43 psi with vac off
NOS kit with dual foggers and 46 fuel/38 n2o jets (I could only get 800-900 psi out of the bottle without the heater)
1 step colder on the stock plugs

The car ran a best of 13.20, best of 105 mph, and a best of 2.0-2.2 60 foot with no tire spin. I started spraying at the 60 foot mark.


This thing should be in the mid 12's atleast! Something isnt right somewhere. Im going to check the base timing and make sure its correct. The car doesnt have much grunt off the line. I mean it leaves hard but is no means a tire fryer, even on the street.

I have these mods to install yet...
Walbro 340m fuel pump
Jet fan switch
Jet stage I chip
160* thermostat
NOS bottle heater

Any ideas on how to make this thing run?

Thanks,
Dale




[Modified by Repoman, 2:06 AM 5/5/2004]

 

Yes, I agree, you should be running faster. I couldn't tell if your car was an auto or not. Let's just say it is and that you have 2.59 gears and a stock stall. That could be some of the problem. The other problem could be that you were running rich on the bottle. The pressure may be alittle low. I don't know your NOS setup, but if it is a "kit" they are usually jetted rich on the fuel side. Oh yea, what is the claimed HP of the jets you are running? You also bumped up the fuel pressure and have a chip that may be giving you extra fuel as well. Just things to think about. Also, 6 degrees of retard may be to much, but probably doesn't hurt. Same with the plugs. Depends on how much NOS your runnin. Hopefully this will get the gears turning. Good luck!

 

Your tune is WAY fat. Even with the jets square (same) somtimes they are fat, with the combination of low bottle pressure and over square jets it is not going to work. Get the bottle pressure up to 900-950 and check the jet map on your tunes.

I am surprised you can't see black smoke all the way down the track

Is that tune for a 100-150 shot?

 

What did it run off the bottle?

I would say the problem is bottle pressure. You really need a very minimum of 900 and it should be at least 950psi for the hit to actually be any good. I have dynoed on the bottle with only 850 psi and gained only 20-30 on a 150 shot.

 

If this is a NOS kit the n2o is #52 and the fuel is #28...for a 110 hp shot.

 

This is the NOS kit with the plate sytem and dual foggers. I went with the 43# fp from advice from other board members. I bought jets that NOS tech line advised on and the car was WAY fat and just fell on its face. The 46f/38n that are in there now came from the previuos owner, it was a used kit. He sad it was a 150hp combo. I get no black smoke while on the spray. It does pick up a bit on the spray but not like it should. I got to the track late last week and only got 4 runs so what its doing off the spray I really dont know. Heck I might only be spraying a .10 off! Guess I should have made a shake down run or two without the spray. Was just to excited I guess. I figured -6* timing was to much but was trying to be safe and not sorry. I did change it to -5* and sprayed off the line. But it just spun the first 30 feet or so and the run stayed in the 13.20's.

What fuel pressures and jet combos are you guys running? I know fuel pressure directly effects the jets sizes according to NOS tech. Every n2o system I have ever used had a larger fuel jet. Are these jets suposed to be the opposite or closer to the same size? The "old" rule of thumb was 5-6 steps bigger on the fuel. Im starting to think tuning my 10 second GN was easier, lol.

Thanks for the help!

 

I run the NX kits, the nitrous pill is always bigger than the fuel pill. A 62 nitrous 35 fuel is a 150 shot in the NX.

 

The earlier comments on bottle pressure is your first concearn. The factory jet map is very concervative, not wrong, but certainly fat. If it were me I would square the jets and run a little extra fuel pressure (7lbs), look at the plugs after a run and pull fuel out at .5 lb increments until I liked the way the plugs look.

For the Fogger on my 454 I ran .019 fuel .022 nitrous / 7lbs and 950 lbs pressure. This little tune made 141 more rwhp and the plugs looked great. I pulled 6 degrees out, which was too much the heat mark on the plug was a little off. I could have gone 2 degrees. I tore this motor apart to build a 572, so the data is a little limited.

 

There seems to be some confusion on the jet maps when it comes to fuel. If you are running your nitrous system off your fuel injection fuel pump, the fuel is at a MUCH higher psi which obvioulsy flows more fuel. If you run a 30 something fuel and 60 something nitrous jet with a low pressure tune (5-10 psi) you will melt every piston you have very quickly.

 

Very true RATT, I was assuming an EFI setup running standard pressures, not a stand alone low pressure system attached or carbed application.

 

After re-reading the post I can't beleive I missed the fact you are running 43#'s of fuel pressure AND over square jets, it was so close to a carb tune I didn't even think FI. Your tune is WWAAYYYYY FAT. There is no way that is even close!!! I don't have any FI tunes in front of me, get ahold of the manufacturer and get a proper tune. Problem solved

 

Ok, here are some tunes from NOS

HP Nitrous Fuel@42+ psi
70 .042 .026
100 .047 .030
125 .055 .039

 

i think NOS gave you the jet sizes for a plate system for a carb ( 5-7 lbs fuel pressure) As we talked about earlier in the week. Start with the 100 at the pill sizes listed above ( .047 N and .030 fuel) with 6 deg base and pull 6 deg to start with and be safe. You can slowly put more timing back into it as you go.

I'll see you Friday if it doean't rain


[Modified by mike 1985, 7:00 PM 5/6/2004]

 

Is that for a single nozzle or dual

 

Got it all worked out I think. We'll see tomorrow at the track.

Got a different tech today at NOS and heres what they gave me for 150hp F=38, N=46 using 43psi fuel pressure. These sizes are for a twin fogger plate setup NOT the spray bar style. He also said up to 5psi fuel pressure difference would not change the jetting. He also agreed to the 4-6* retard in the timing and one step colder on the plugs. I have the jet sizes for 100hp and 125hp also but I left them at the shop. I will post them later in case anyone else is looking for this info.

I also found this site that seems to be very acurate when trying to calculate jet sizes. http://www.robietherobot.com/NitrousJetCalculator.htm

So I put the jets in, had 975-1000psi bottle pressure, took out 6* of timing with the msd box and sprayed away, lol. Seem to pull hard with no problems. I could probably get away with only taking 4* out. Still not the kick in the pants I thought it would be but you can feel the difference.

I'll post some new times friday after we get home from the track.

See you there Mike!

 

that's great. Most likley you can get away with 4 deg retard, but make a pass with 6deg then 4 then 2 then none, so long as the MPH continues to climb your not in detonation.

Sorry to be the bearer of bad news nut the 100 and even the 150 shot on a stock TPI will be pretty lame above 2500 RPM, the biggest diffeence is out of the hole, if we had more time i'd let you borrow my rear tires and spray it off the line for some 1.75 60'...


Mike