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-   -   Most Timing experience needed carb and turbo!!! (https://www.rx7club.com/new-member-rx-7-technical-256/most-timing-experience-needed-carb-turbo-965624/)

13b-rotary-vw 08-11-11 10:25 PM

Most Timing experience needed carb and turbo!!!
 
How does the timing effect carbed and turbo setup's??
I would like to run a crank angle sensor from a FI system on my carbed setup. What I find confusing is when turbo guy's "lock" their dizzy. If the carbed setup needs to have timing advanded then I can possibly make my own electrinics to do that. Who out there can help me out with this????

Aaron Cake 08-13-11 10:03 AM

That's the problem with carburetors and distributors in a turbo application: you can make it run really well at one load point (say, wide open throttle) but it will run terrible everywhere else.

For example, locking the dizzy at 15 degrees to be safe in boost means: poor mileage, lackluster throttle response, glowing turbo manifold, poor midrange performance, poor overall performance in vacuum. But letting the dizzy properly advance for decent drivability everywhere else but WOT means that far too much timing will be called for under boost, and boom; apex seals in the muffler.

If you are intent on running the carb and not locking the dizzy, then build a simple Megasquirt setup to run the stock CAS and a set of 2nd gen coils. That will give you load-adjustable timing just like an EFI setup. Just use the MS to control timing and ignore the fact that it can control fuel...or even better, convert to fuel injection.

13b-rotary-vw 08-13-11 03:12 PM

Cool,
Hey thanks a bunch Aaron, I will look in to the megasquirt setup. I do actually want to run a stand alone FI setup later to minimize engine components in my engine compartment. I will possibly build my own intake plenum to better suit my needs.


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