TrimDrip

So last weekend I was going to the race with my mechanic. I asked him about the pro-mod we have here in town that hasn't run in a colple of years about a what kind of electronics and wideband it used. (I wanted to buy since the guy has been buying up parts the last 2 years) The guy looked at me like huh? I explained something to see the air/fuel ratio in the car for tuning purposes. He told me they didn't use one. So I asked in suprise, you are running a 3500hp blower car that leaves at 3g forces and runs 4 second flat passes without something to give you an idea of what the air/fuel ratio is at? Yes, then he explained. . . I am still amazed they were able to win like this with todays technology against them. He also said that the car was capable of more seeing how it weighed 1200 lbs more than the other cars in the class. His estimate was in the 3.60s on a good track in a car that weighs less, IF it could hook.

67mustang302

I assume you're talking the 1/8th.

And yeah, you don't need wide band tuning, though it is nice, to be fast. There are guys, myself included, that still tune by plug reading and trap mph. Plug reading tells you what's happening inside the chamber during combustion, and tuning for mph provides the best average usable power for the vehicle. Modern tuning aides take a lot of the guesswork out of it, and that's why you're seeing fewer and fewer guys who understand the combustion process and how to interpret it's after effects.

Usually the fastest guys I see at the strip aren't necessarily the ones who have the best tuning devices. The guys that come to Famoso and win things like the March Meets and Hot Rod Reunions aren't always tuning for ideal AFR. They'll tweak the tune to control traction off the line, shifting gears, control the power to make it easier to drive more consistently etc.

TrimDrip

yes it is in the 1/8th.

He explained something like you are talking about.Slick track tune-ups with the mains and using a 2 or 3 stage lean-out.

He also made out the reason Jason Scruggs ran a 3.61 (that he didn't back-up) was because of him riding the clutch. They don't zero a clutch in after a pass, they replace it.

67mustang302

Yeah, the clutches on those cars are wild. Multi disc setups with controlled engagements. Too much clutch too soon and they lose traction, not enough clutch and they run slower than they could. The big fuel cars run clutches that have like 6 discs and they basically vaporize the clutch pack by half track. It's kinda neat watching the bigger cars run, leaving a trail of black carbon dust behind them for the first several hundred feet as the clutches get used up.

AdderMk2

fuel metering in those cars is nothing like what we have. A typical "wideband O2" like we would use in our cars, is useless to them due to the amount of fuel and type of fuel they burn.

not to mention, it would probably melt in the exhaust tube

TrimDrip

I don't know about that.
He runs an alcohol blower car and people run w/a injection on there cars all the time.
I was just using common sense instead of knowledge.

TrimDrip

That is how he knew Jason was doing it. These races don't pay like the bigger racesand this guy just has more money than he knows what to do with apparently.

Charles has beat Jason 2 out the 3 times they made it to the finals. Everytime Jason loss was because he had it tuned up to much and blew the tires off.

67mustang302

Yeah, you get greedy with the clutch and you end up with 0 traction down the track.

And with alky you can run tuning aides, but I think Adder was talking about nitromethane. That stuff has a combustion temp of around 7,050 F(iirc gasoline burns in an engine at around 1/3 of that temp). The exhaust gas temps are insane on a nitro car, so much that the heat energy disassociates hydrogen and water in the atmospheric moisture, and as it exits the pipes it recombines in combustion, making the characteristic white flames of burning hydrogen. Like he said, you stick a probe in that pipe and it would just melt.

AdderMk2

A typical wideband O2 sensor couldnt even read the emissions of a alcohol car... they run like 4:1 and ive never seen a wide band able to read lower than 10:1

TrimDrip

I think I am going to go with the Zetronics unit. 279 is the cheapest I have seen but, I hear they can be found cheaper.

I heard today that Charles done bought another car and this one is going to be around the same weight as the others. The entire car is made of carbon fiber and it is going to be not as wide as the other. He is going to keep the Keith Black Hemi block and the Whipple blower. He is also going to run all the electronics of modern tech.lol
Sounds like he is going for the World Record in the 1/8.