I have an 87 iroc with a 305 tpi. I am running 14.8 @92 mph with a 2.4 60 foot time. With a 100 shot wet kit what times can i expect. When i went last time i sprayed only in third gear and ran a 14.4 @99mph. But i was mad because it surged
can anyone help.

 

you gained 7mph spraying in 3rd gear on only a 100 shot? Seems excessive. Anyhow, what was your bottle pressure, jetting, fuel pressure, bottle orientation, percent bottle full, etc?

 

surging is a sign of a low bottle 99% of the time

 

The juice depending on when he hit it could have improved his 60' times enough to give him an increase. Also deep staging will cut down on your mph as well. With a proper suspension 1.2-1.4 sec. is not unheard of for a 100 shot. Especially considering the the heat soak problems the tpi cars have.

 

the traction problem cars I have seen totally lose it in the 60 ft when juice is applied

 

If you’re running a 2.4 60’ then that is a problem that you’ve got to fix before you can expect to run decent times.

Even a 14s car has the power to run 1.8-1.9’s, and f-bodies can do that with a stock suspension on radials (the best I’ve run on a stock suspension and radials was a 1.71 in a manual tranny car).

Once you take care of that you should be able to expect about 1 second and 10mph from that 100 shot

 

PETE: What do you mean by "Heat soak" problems on TPI cars?

 

With TPI being the size(mass) that it is, once the thermostat opens and runs one complete cycle the heat from the coolant gets transfered into the metal. If you've ever wondered why TPI cars run like raped apes when cold only to feel like your pulling a trailer after you've sat in traffic a while, that's your answer.

When N2O changes from a liquid to gas(394* I believe) the chemical reaction releases oxygen trapped inside the nitrogen molecules. during this reaction the ambient temp of the gas falls off quicker than a fat chick on a big wheel. That drop in temperature alone really helps cool the charge being ingested. That is the second benefit of N2O.

 

Pete… let me tell you, I’ve got over 400passes, carefully logged in a spreadsheet for temp, conditions, time between runs or from when I pulled off the street and went through tech… mostly between an LT1 and TPI (L98) cars. TPI is a really weird beast compared to the LT1.

I will agree that the TPI plenum seems to heat soak and stay seriously hot while sitting in the staging lanes. Often on a warm day it doesn’t drop to be cool enough to put your hand on it and keep it there, where an LT1 will cool relatively quickly. OTOH, while running, TPI’s stay cooler then LT1 manifolds and I’ve found that I could document an improvement with cooling and even icing an LT1, where TPI’s will run just as fast right off the street or hot lapped, and I haven’t been able to document any changes from icing the manifold any length of time (assuming that you keep coolant temps at reasonable levels).

 

I've asked this question before but not got a very satisfactory answer....Does a TPI 305 need timing retarded when running only a 100 shot of NOS or will the standard knock sensor be enough?

BottlefedIroc: What setup do you have?? is it standard and spraying or are you retarding the timing?

 

Does it need it? No, as long as you’ve got a well tuned setup, no detonation and I’d be running plugs 2 steps cooler. Would I run one, yes. When spraying engines become much better at producing max power over a wider range of timing settings (often as much as 10*), so you can usually retard timing quite a bit without loosing any power with no consequences besides a much safer setup for your engine.

 

my timing is set at 6 degrees before top dead center. my 60 foot times were a 1.9 before I put a 2800 stall in my car. The street tires just cant hold it. Thats why my 60 foot times really suck. I really need some radials!