304 Power Curve

[Holden202T]

if you loose any traction taking off then slick WILL NOT slow you down!

I had a motor making 150hp at the wheels the first time I ran my Gemini down the strip, and did 14.5 with something like 10-15mtrs of wheel spin, the slicks literally took a second off that time!

if you get any wheel spin at all your tyres are not good enough, if you don't then you need to spend more time elsewhere!

[delcowizzid]

yeah we ran slicks once on the vb after seeing it hook up i havnt raced a car at the track since due to it not being worth it on street tyres and i cant afford slicks LOL they dropped over a second on the vb.you do want some spin about 5% on the launch dead hooking normally costs time.they dont feel nice at the fast end of the track at 210kmh with 12psi in them is the only downside LOL

[Grim304]

Its not rocket science, as I said if I changed to slicks with the car as it is I will run slower.
I am not getting any wheel spin off the line as this is what I anticipated, a bit surprised I don't but I was hopeful I wouldn't as I run a stock stall converter and I am trading off launch speed for traction while not wanting to change my convertor yet.
The reason I would run slower is that I would raise the gearing by putting my slicks on. When I decide to lower the diff ratio or I start to break traction then yes that is when I will revert to slicks.

When I change my diff ratio I anticipate a change in traction off the line and then I will need the slicks, maybe if the new intake performs well that may push my traction past the limits.
I could break traction of the line if I changed my launch style but because I slightly load the trans up it takes the abruptness away and allows a smooth launch.
I am sure you will understand DYO is about 2 things, consistent times and reaction, my worse reaction in the past 2 competitions at the drags has been 0.109 and my best 0.009, I haven't been beaten in 2 rounds. Shit now I have tempted fate

[v8-tuning]

Forget slicks go a set of et street radials once traction is an issue.
Car will trap slower with slicks and simply not needed.
I just flash it of the line,i find stalling results in a slower et.

[Grim304]

Yep, I agree on stalling being slower, I am only running 14.3 at under a 100mph at present, not worried about anything except my reputation as being one of the best DYO racers around here.
The car in it's present form is an honest performer on the street and dam easy DYO car but I want it to run easy low 13's all day long and if it can crack a 12 then that's a bonus.
I don't think I can take the National series this year as I am not going to Auckland to compete but I am wanting to be the top IHRA DYO Street car in the South. so any mods may have to wait til after the next round in January.
No doubt the Dodge who ran second to me and the GT who ran 3rd will be trying to stop me

[Grim304]

I have a question, if I were to test my car using a 4-barrel carb, as I now have a manifold, what do I need to turn off?
I know I will need to drop the pressure from the fuel pump
So I guess I turn the entire fuel off?
But there must be quite a bit of other stuff?

[Holden202T]

not really, you leave the tps connected and just unplug the injectors.... weather you install the MAT or not I guess is up to you, we didn't.

once the ecm sees the tps not moving it will throw a code then the motor will run on the main spark table

Jayme has done this on a mates 304 once and I have done it on my 202 in my brothers car as well and it works fine.

oh and I forgot to mention, you might want to disable some of the codes so it doesn't show CEL all the time from the missing stuff

[Grim304]

Thanks for that, it sounds pretty simple really.
So tempting, I might talk to the head/cam man as he was hinting that a 600 would be a bit small for my cam and heads and that I should be looking at a model double pumper I haven't heard of, just as a reference.

[vc81]

So what's the best way to mount the TPS to the carb???

[Holden202T]

I believe there is a holley kit to do it, not cheap though, but if you leave the TPS connected to the wiring loom and not connected to the motor at all it will throw a fault code because the engine revs are increasing but the TPS isn't moving, once that happens the ecm will then run off the main spark table and not the idle one then you can use it without the tps referening throttle position.

you could go to the effort of getting the TPS connected to a carby but in my opinion theres no point!

just simply having it as suggested above made a cranky methanol carby 202 idle and rev so much smoother than with the dizzy controlling the spark!