TOOOFST Nitrous/VEC1...dyno results (pics)

[Jack B]

Scotty:

Once again, no flame intended, but think about the following. At 4300 rpm you are about 360 hp (NA) and 560 hp on the bottle - that is a two hundred shot. Nitrous is a fixed entity and you should get close to that extra 200 hp all the way out to peak hp at about 5400 rpm. This is not the case on the published pull, the hp peaks at 4300. The nitrous is not going to drastically change where the peak hp occurs, that is an indicator that the nitrous is dropping off, either a mechanical issue or low bottle pressure. Because of that notchy drop just after 4300, I would think a solenoid issue.

I am in no way trying to take away from a very nice install, just pointing out there is more to be gained.

 

[2001 GTS]

Hmmmm....bottle was at 1000psi

Scotty...what you think is going on

 

[PRVT JET]

Steve, I had the same set-up, with 40/30 jets I only made about 100rwhp. I made 150rwhp with 47/32 jets.

Isaac

 

[2001 GTS]

Hmmm...Jack, you sure it isn't all the fuel catching up to the nitrous flow...it does go from an a/f of 14 to 10-11 pretty quickly

 

[Jack B]

Here are facts:

1. The car is putting out approximately 200 hp at 4,300 rpms.

2. That is about 600 lbs of nitrous per hour and 100 lbs of fuel. The nitous flow should be fixed by bottle pressure, jet size and the pressure drop across the system.

3. The hp is made by the fuel, the nitrous is the oxidizer.

4. The car Is relatively lean before and at the 4,300 rpm point. It might be running closer to a 7:1 nitrous/fuel ratio.

5. After 4,300 rpms the hp stops climbing. That point is marked by a negative vertical notch of 30 hp - something happened to the nitrous flow. My reasoning is, if the nitrous flow remained the same, and the fuel leaned out further the hp would continue to climb. However, in this case the car started to run richer, the only reason can be the nitrous flow tapered off.

In addition, I have dozens of the same type of dyno plots where I was having solenoid issues on my own car. I would look for low bottle pressure or low voltage at the solenoid, which allows the solenoid to slightly close. When you are talking about a solenoid that opens thousands of an inch, it takes very little to reduce the flow.

On the positive side, the install looks goods, it made a lot of hp without a lot of tuning and it is going to make more.

 

[2001 GTS]

Ok...what do you suggest I do about the soleniod...it was rebuilt not too long ago

 

[Jack B]

Do you have more pulls to see if that same notch is always present? That drop in power has to be associated with the nitrous flow. Maybe I wasn't clear before, but, the hp should still peak close to 5200-5400 on a lightly modded car. Your hp drops off early. That tells us the nitrous flow has been reduced. Take a look at the other current post on nitrous, it goes into a little more depth. Like I said before, you are putting out nice hp and the a/f is good, basically you are running like a lot of other cars, maybe you don't need to extract every last piece of hp.

Scotty:
This is not Jack the Nitrous Guru, just someone who wants to help, in addition, someone who has a couple hundred nitrous pulls trying to make it work. Everyone of those has been analyzed and reanalyzed. You ought to be proud, I have your old setup over 800 hp, maybe 850.

 

[2001 GTS]

Only did two pulls.

But I would like to know what numbers I can intimidate people with

 

[Jack B]

If you have headers and exhaust, you car is capable of 600-625. There are a bunch of similar cars with those numbers. Depending on what you want to do, it may be time to invest in a a/f logger - take a look at this:

http://www.innovatemotorsports.com/xcart/customer/home.php?cat=248