Luke Skyjacker

iTrader: (1)

About to put my intake and carb on, but I'd like some suggestions for the carb tune up. What jets, air bleeds, PV, pump size, pump cams etc.

What plugs would work well in this app? I have used NGK and like them but that was with my SBC.

The car is a RX7 at around 2250# with no driver. Powerglide big stall converter, 1 7/8 headers. 4.56 gear with 295/65/15 DRs. Fuel will be 89 octane gas.

speedtigger

iTrader: (16)

Each car is different. I would say start with the factory sizes on everything and tweak it to solve any problems you encounter. In general lighter cars with higher numeric ratio gears do not need as much pump shot duration and might rev a little faster if slightly leaner. Other than that, I can't think of anything until you try it out.

Luke Skyjacker

iTrader: (1)

I'm just looking for a baseline to start with. I guess I could find the paperwork that came with the carb.

ZONES89RS

iTrader: (25)

That is allot of car around a stock motor man, it is going to be interesting. That is set up for a cam, so a smaller jetted setup with 68 primaries and 72 secondaries will probably work, use whatever air bleeds you have to see how it will run with whatever else is already in the carb just to get a base line.

Luke Skyjacker

iTrader: (1)

[QUOTE=ZONES89RS;14320656]That is allot of car around a stock motor man, it is going to be interesting. That is set up for a cam, so a smaller jetted setup with 68 primaries and 72 secondaries will probably work, use whatever air bleeds you have to see how it will run with whatever else is already in the carb just to get a base line.[/QUOTIE] i've been meaning to PM you for some info. I'm gonna be moving back to the Houston area in may and my mom lives near Conroe (midland). I'm gonna try the jets you suggested, I'm still gonna have to wait till I get my MSD 6010 to fire it.

Pop N Wood

iTrader: (1)

If you read through the stickies you will find the details from a couple dozen different cars.

Should get you really close.

ZONES89RS

iTrader: (25)

Well, welcome back to Houston, maybe i will be able to give you a hand with it man, do you have any carb tuning equipment?

Luke Skyjacker

iTrader: (1)

I have an assortment of jets. I can get air bleeds and pumps from a buddy of mine. I looked through the stickies but there kinda hit & miss with people having more modified engines and lacking info on carb settings.

ZONES89RS

iTrader: (25)

Yea man, you are going to have to start lower and then work up or down to see what the engine does and doesnt like to respond to.

Luke Skyjacker

iTrader: (1)

it's actually not much of a car at 2200-2300 lbs! LOL but I know what you mean. I have always wanted to see what one of these motors would do in a dedicated drag car. Cool thing is I'm setting it up so I can still drive it in the street.

How strict is the tech at HMP? I know there are alot of cruise Ins and car related events in the area. I'm really looking forward to that.

xpndbl3

iTrader: (23)

I'd leave the primary secondary gap much larger than 4 sizes, since the power valve is worth 6-8 and the secondary would need to match it. 70/78 would be my starting point, might need a 50cc pump shot kit up front, you'll know soon enough I suppose. Lots of threads on it, best bet is to start with the stock jetting which can be googled and go from there. A wideband is a great tuning tool to purchase

Luke Skyjacker

iTrader: (1)

Wideband would be pretty nice, I just don't havevthe funds at this point. As it is now I am gonna have to wait a few more weeks to get a msd 6010

xpndbl3

iTrader: (23)

Well then reading plugs isn't too bad, and you can always take pics and post them too.

ZONES89RS

iTrader: (25)

Tech? It is a joke if you have a street car, but once you go too fast, they are hit and miss, there have been nights i got and run 7.6 and they dont say anything about me not wearing a helmet, other times, my buddy was running 8.4 and they would not let him make another pass without a helmet, just be prepare with safety equipment in case you need it.

speedtigger

iTrader: (16)

It really sucks when they say you are not making another pass without a cage. That is a little tougher to borrow.

Luke Skyjacker

iTrader: (1)

I fount the paperwork that came with the carb. Called for 74P-84S jets with a 4.5 PV. I only had a 9.5 PV or a plug so I used the PV. If I have midrange issues I guess I will start there. I know I changed the pump cam and the airbleeds but I will just see if I have any drivability issues. Thanks for the help guys.

How hard is E85 to get ahold of in Houston?

speedtigger

iTrader: (16)

9.5 is pretty high. If you have much cam in the car, it may cause you some very
rich idle problems.

Luke Skyjacker

iTrader: (1)

Cam is stock LQ4. I thought it might be too much also. I'm gonna pick up a 4.5 while I'm out tonight.

ZONES89RS

iTrader: (25)

Not too bad, it is not super easy to find, but it is out here, just depends on where you are at.

slow67

iTrader: (2)

You can't say that for sure unless you know the PVCR diameter.


Not true either (unless your carb is setup wrong) as the power valve only feeds the boosters (unless the power valve is blown).