I am trying to keep things simple, and getting the RC 1300cc injectors. What are the 550/1300 combo good for? And what are the 850/1300 combo good for?

I am going single right now, and am trying to get a simple fuel system that can handle the job well without loads of $$ and custom fab.

 

550/1300when i was getting my car tuned, steve told me he could get around 340 with stock ports and other supporting mods... however, i had some issues and i did not

i have a friend with 550cc/1300 on a single and hes got around 350whp

 

http://www.rx7.com/cgi-local/3rdgencalc.cgi

 

I ran 550/1200 with non-seq and made 347whp at 1 Bar with the duty cycle around low 80s. When I went single with the same engine, at 1 Bar duty cycle went up to about 87%. That is when I went to 1600 with the FJO driver.

 

hmm, ok.

I am going with a T04E, so I won't be in the 400's. Most likely in the 370+ are.

So basically my only option is to go with a larger secondary (bigger than 1300) or would running 850 primarys help?

Other option would be 550s with 16xx's? Are there other options aside from the KG rail kit?



So that little calulator thing came up with 446 fwhp with 550/1300 at 80% duty, and 519fwhp with 850/1300.

I think to start I will drop in the 1300's and see how it is during tuning. If I need to I'll buy some extra 850's and throw them into the primary. Seems the easiest option.

 

max 400, you will have a high even peak cycle duty i bet

 

i thought u can get like 380-390whp safely running 550/1300's?? while stayin under 85% duty

 

well, does anyone know what kind of % drivetrain loss the FD has?

 

No - but 15% is ballpark.

 

Click on this link http://www.turborx7.com/fuelsystem.htmthen scroll down and has different injector combos and approx rwhp and work duty limits.

 

Not to jack the thread, but if I were to get 550 primary and 1200 secondary, would I need to run resistors?

 

^^ Yes you will need to run resistors on the 1200's, and the 550's should be stock so no.

To the OP, a good option for you is to go with a 550/1600 setup. It should suppourt the power range you are aiming for while still being fairly easy to tune. 850cc primaries can be complicated to get tuned properly and you will most always run really rich at idle. I know, I currently run 850/1680 and my idle refuses to lean out past 11.1 =/- 0.02. This though is truly just a limitation of the PFC so if you are running another fuel management system then you may be able to bring it leaner.

 

Resistors are not required if the 1200s are bored out stock 850s.

 

agreed if there bored out stockers then no resistors are needed.. when you go topfeed injectors thats when you will need resistors.

 

to the OP: no resistors are required for those injectors

 

Most if not all the 1200 1300 cc for the rx7 are bored out stockers. So +1 to no resistors. Also 850cc primaries can be leaned out more with the datalogit and running negative lag.

 

I have a PFC and datalogit... i dont plan to tune it myself. most likely get forcefed here in vancouver to do it, and when steve kan is around the area either here or seattle get him to work his magic.

I am going to try out 550/1300's and if I need it after the initial tune I will get some 850s in the primary location.

 

My mistake, I was refering to top feeds not the bored out stockers..

And Steve could not seem to get my 850's to lean out any more than what I stated with a stock-ported motor. He complained of limitations with the pfc. Obviously he was using a datalogit. Car was tuned twice, once at the shop in ft. worth and once a few months later at my house.

 

Not all top feed need resistors, but on the same token I'm not sure if anyone does make a saturated injector above 850cc, they usually move to the peak and hold design which require resistors for the power FC.