Dyno Striker heads/cam car on NOS/propane Creampuf

[FastMatt]

Some info I thought you guys would like to see.

Well in short I think I figured out that Using Propane as the added fuel and not GAS = WAY less power then you jet for.

This car when I did the heads/cam on it 3 yrs ago made 612 rwhp and 619 rwtq. All motor Yesterday it Dynoed 592 RWHP and 599 WRTQ. Thats with 3.55 gears

There have been a few changes made to the car in that time, it was running Parelli 355/25R19 rear tires (25.9" tall) 3yrs ago, I'm now running Nitto NTO5R's in 345/30R19 (27.5" tall). I here that the taller stickier tires can account for some loss of power on the dyno. Also 3 yrs ago my A/F was creeping up to about 13.8 to 1 and at that when it was very hot out I was getting a little pinging. This past summer I had Chris at DC richen up my programing to 12.6-12.8 to 1 and the pinging went away. So those things togeather (and 3 yrs of beating on it) have netted a 20 rwhp and TQ loss.

Now here comes the NOS

Seeing how I was going to be planning on playing with NOS jetting, I mixed 25% C16 in the take with 75% 91 pump, just to be safe.

I have a OLD BTR NOS/propane kit that uses the NOS Dry kit at the hart of the kit. It suplyes the extra fuel Via the Fuel injectors by telling the ECT the AIT, and the Coolant temp are like 30 deg. This works grate for the first ~125hp on a stock car. Then BTR used the propane for the added fuel past that for up to another 100 hp worth of jetting. But on a heads/cam car like mine were the injectors are already running close to maxed out it does not supply the fuel needed for that.

So what I decided to do was just jet the propane WAY up to support the fuel for nearly all of the NOS jetting because I was not going to get much more out of the Injectors in the way of fuel.

My first pull with the NOS was on the jetting I had been running on the street for quiet some time, #50 NOS and #55 Propane This should be a 225hp shot. This only netted me 706hp, strange only picking up 114hp on a 225 shot? A back up pull netted the same thing. A/F was in the mid 11's. Next I put in #53's in the NOS (250 shot) this netted me 12 more HP at 718 rwhp and a A/F of 12 to 1. What the heck.

Thinking the propane had to be the problem, I went with #32 jets in the NOS and Turned the propane bottle off and drained the line. This should be a 90 hp shot. I figured there had to be at least that much fuel left in the injectors, and I had some race gas in the tank so if it went lean I would probly still be ok. Well that netted me 668 rwhp So a gain of 76 RWHP on a 90 shot. But my A/f was at about 14 to 1, leaner then I would like to see on NOS.

So by jetting for 90hp and No propane I picked up 76 rwhp
And by jetting for 250hp and using the propane I only ganed 126 rwhp (+50hp from +160hp in jetting??)

Next I went to #40 jets (140hp) in the NOS and #24 in the propane This got me 695rwhp so a gain of 103 rwhp my A/F was ~13 to 1

Next I went to #42 jets (160hp) in the NOS and #34 in the propane This got me 694hp, so a Gain of 102hp, my A/F was ~12 to 1 (lost 1 hp by adding 20hp worth of NOS and more propane)

At this point I figured there was no point it trying to make any more power with the propane. Going from 140 hp jetting to 250hp jetting using the Propane as the fuel only gained 23hp.

I did 2 more pulls all motor just to make sure I did not hurt anything with that 14 to 1 on the NOS pull and it made 592 rwhp , and 591 rwhp. So I drove the car back home 120 miles, man this car is fun to drive


I guess it's time to ditch the Propane and do it Wet with GAS! Anybody know how far the stock fuel pump can be pushed with nos?

 

[jrod_okc]

Sweet! I would ditch the Propane.. Sounds like Something IPO would have done back in the day. LOL

I am going to get mine on the dyno this week and see what i make.

 

[fe4snake]

I was talking to Sean Roe yesterday regarding a NOS setup for my car. He told me that the stock fuel pump was only good for about 650 RWHP and that I should consider a Walbro 255 pump instead of the factory 215 pump for NOS use. As far as the stock injectors, he said I should try to tune the motor first with them and to watch my A/F. If the A/F gets too lean than I should change the injectors.

 

[plumcrazy]

sean gave you some good info

 

[Jack B]

I was talking to Sean Roe yesterday regarding a NOS setup for my car. He told me that the stock fuel pump was only good for about 650 RWHP and that I should consider a Walbro 255 pump instead of the factory 215 pump for NOS use. As far as the stock injectors, he said I should try to tune the motor first with them and to watch my A/F. If the A/F gets too lean than I should change the injectors.

I ran the propane for several years and finally gave up on it. The problem is that the propane pressure drops off quicker than the NOS, therefore, it is harder to keep the a/f linear especially during cooler weather.

If you are running the oem injectors they are already static if you are pushing 600 hp NA. My car has the 255 and BAP and I have run a 350 shot on top of 550 NA. The fuel pressure drops a little, but, the NOS pressure also drops near the end of the quarter, therefore, the a/f stays consistent.

I found it far easier to spray the fuel in the tubes. The nos/fuel mixs better and you get better distribution. It is also easier to tune and you have more flexibility. You can spray in the tubes, then fine tune with the injectors.

 

[fe4snake]

I ran the propane for several years and finally gave up on it. The problem is that the propane pressure drops off quicker than the NOS, therefore, it is harder to keep the a/f linear especially during cooler weather.

If you are running the oem injectors they are already static if you are pushing 600 hp NA. My car has the 255 and BAP and I have run a 350 shot on top of 550 NA. The fuel pressure drops a little, but, the NOS pressure also drops near the end of the quarter, therefore, the a/f stays consistent.

I found it far easier to spray the fuel in the tubes. The nos/fuel mixs better and you get better distribution. It is also easier to tune and you have more flexibility. You can spray in the tubes, then fine tune with the injectors.

Do have a single pump or dual pumps? What size injectors are you using? Also, I have been told by my local speed shop that if I want to run the standing mile runs I should use the dry NOS instead of the wet NOS system.

 

[FastMatt]

I ran the propane for several years and finally gave up on it. The problem is that the propane pressure drops off quicker than the NOS, therefore, it is harder to keep the a/f linear especially during cooler weather.

If you are running the oem injectors they are already static if you are pushing 600 hp NA. My car has the 255 and BAP and I have run a 350 shot on top of 550 NA. The fuel pressure drops a little, but, the NOS pressure also drops near the end of the quarter, therefore, the a/f stays consistent.

I found it far easier to spray the fuel in the tubes. The nos/fuel mixs better and you get better distribution. It is also easier to tune and you have more flexibility. You can spray in the tubes, then fine tune with the injectors.

Do you just turn on the BAP with your arming switch?

Are you running that 350 shot out of just 2 nozzles in the Tubes? (one in each?)

Whats your Jetting for the 350shot?

Are you still running the NOS dry kit as your "base kit" and tricking the ECU?

What kind of times does your car run with 550 RWHP N/A and the 350 shot on top of that?

 

[Russ M]

You are playing with fire running your car so lean, you should be 11:1 and the factory pump is good for roughly 600rwhp at that a/f.

 

[EllowViper]

On a N/A motor I'd shoot for 12.5 AFR on a relatively cool fall day. Max torque is achieved at 13.2 AFR. If you were going to be on the juice for a sustained run (standing mile or something), I'd dial the AFR a bit richer...around 12.0 For messing around on the dyno or street, 12.5 AFR is reasonable if staying N/A.

 

[V10TT]

I don't understand why it would make almost no gains in HP as the jet increases. Looks to me like you are just not getting more Nitrous into the motor as you increse jets.
Questions for you:
Do you have the big -6 line from the bottle to your NOS solenoid?
Do you have (2) big solenoids, one for each side of the motor?

An idea for the fuel system is just to have either a dedicated pump with its own regulator running out of the tank and feeding the fuel solenoid, or the same thing just running off a 1 gallon fuel cell where you culd just run C-16 on it.

That way your motor tune, injectors, and fuel pump do not get affected.

I still suspect you are not getting more nitrous in with the bigger jets. You need to upgrade feed lines and solenoids.

 

[FastMatt]

I don't understand why it would make almost no gains in HP as the jet increases. Looks to me like you are just not getting more Nitrous into the motor as you increse jets.
Questions for you:
Do you have the big -6 line from the bottle to your NOS solenoid?
Do you have (2) big solenoids, one for each side of the motor?

An idea for the fuel system is just to have either a dedicated pump with its own regulator running out of the tank and feeding the fuel solenoid, or the same thing just running off a 1 gallon fuel cell where you culd just run C-16 on it.

That way your motor tune, injectors, and fuel pump do not get affected.

I still suspect you are not getting more nitrous in with the bigger jets. You need to upgrade feed lines and solenoids.

Had me stumped too, I just figured it had to be the propane.

The NOS feed line is -4 (I was told yrs ago by a rep at NOS that that was fine up to a 300 shot), but I may be mis informed


It only has 1 "big" solenoid for the Propane, and one for the NOS.

 

[V10TT]

I suspect if you add aonther big solenoid to feed the motor with one solenoid per side, and a -6 from the bottle to the solenoids, you will start to see the logical gains from the jet increase.

Propane is the fuel, but you need the Oxygen in the nitrous to make more power. I'm not sure what is the orifice size in your N2O solenoid. Howerver (2) .053 jets is equivalent to one .075 orifice size based on surface area. So unless the hole in the solenoid is considerably bigger than this, increasing jet size is not going to do much.

Go with a -6 main feed, and two pro shot N2O solenoids, and watch the hp go up.

 

[Chuck 98 RT/10]

So what's the going price on a set of Stryker heads?

 

[Russ M]

About 12k for the complete job if you do the work yourself.

 

[ViperTony]

So what's the going price on a set of Stryker heads?

I'm guessing $5-6K for a set of Stryker heads.

 

[Jack B]

Do have a single pump or dual pumps? What size injectors are you using? Also, I have been told by my local speed shop that if I want to run the standing mile runs I should use the dry NOS instead of the wet NOS system.

Single 255 with BAP and 50 lb injectors. When you say dry, are you enriching at the injectors. In the mile you will only want to use the NOS for a bump at the top end, you will lose bottle pressure quickly for large shots over long times and you cannot pre-tune because you cannot simulate the same conditions.

As stated earlier, because of the crossover intake it is hard to get homogeneous mixing of the nos/fuel if you only enrich at the injectors. It seems like a lesser method, but, spraying correctly in the tubes has many advantages.