Is there a scientific way to figue out exactly how much fuel my car will need? I am buidling up a street ported, hybrid T04b v-trim engine with a Microtech, and am trying to figure out how to pick the right sized injectors for the engines fuel needs.

Are there some sort of fuel calculators, math equasions, etc... out there that will tell me what I need to know? Also, how do I find the input figures for those calculators?
-a

 

http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

Thanks again Max

 

Will the input numbers be similar for an S5 TII with a hybrid?
-a

 

I have a reallly simple method that seems to work pretty well.

Take your target rwhp, multiply by 10. That is the minimum number of cc/min worth of injectors you need.

So for 400 rwhp:

400 x 10 = 4000 cc / min of fuel injectors total... so you could do a pair of 550 cc and a pair of 1600 cc and you'd be in the right neighborhood.

 

Hmmm....this seems simple enough (which makes me a bit suspicious)
So...my turbo can support about 330-350hp...but Im only looking for 300.

That means that we will use the 350 number to be safe x 10 = 3500.
3500 - 1100 = 2400/2 = 1200's for secondaries.

Are there even 1200's for secondaries. Or does it just make sense to get the 1600's and tune them down?
-a

 

I dont think you'd wanna lean 1600s out that much.

 

I'm not 100% familiar with what options are available for an FC, but if you really only want 300 rwhp, I wouldn't put in 1600s as secondaries unless that was the only choice. 1600s dump in a lot of fuel when they kick in and can be tricky to tune to be smooth (but you can definitely do it at least on FDs).

On the other hand, I think once you have a 300 rwhp, you'll want a 400 rwhp one, so maybe if you're going to go to all the trouble to upgrade the system, you should build some extra room into it.

For example on my car (about 406 rwhp), I have 2x550 and 2x1600 (4300 cc/min).... I have been thinking of going to 850 primaries so that I can turn up the boost more

Brian

 

Unless your engine is only stock ported, its hard to estimate fuel consumption in ported engines. To give you an example, my stage 3 engine typically requires approximately 12-15% more fuel than a stock ported engine. I have tune ported engines that requires the same fuel as stock to as much as 18% more fuel. The calcuator can give you the approximate ball park figure but I would add another 5% of top of what it says for safety margin

 

The engine is street ported..
I'm told the turbo will max out at about 350hp. And I am positive that I will not need more than the 350 that that turbo will push. The car is being built as a daily driver, so any more than 300-350, and there can be some serious problems.

I wonder if there are 1200's available for FCs.
-a