Injector size. bigger is better ? or not...

[Nexius]

I have a 98 eclipse GS-T with a big 16G. Now I know I would need 550's but I will upgrade the turbo in a few months so can I run with 660's or 750's on a 16G? And most importantly what are the disadvantages of running with larger than recommended injectors ?

Thanks
Nexius.

 

[Atari007]

I may not be correct here (so correct me if Im wrong).. but I dont see any problems running larger injectors if you use a good fuel pressure reg, and cut the pressure down... a lot... just my 2cents

 

[rdrkt]

The biggest advantage of running a big injector is that when you lean it out on the afc you will get really decent timing advance. If you are looking for injectors I would recommend the bosch 650s they work ok, they are dirt cheap compared to some of the others, and they will provide more than enough fuel for most setups. I would definitely recommend a real fpr because that will go a long way in helping you fine tune things.

 

[Nexius]

It seems logical but if you're right wouldn't everybody be running huge injectors on their cars ? And are you shure that the fuel pressure would be affected by the larger injectors ? I thought the fuel pressure reg took care of that. Even the B&M FPR can only increase pressure from stock and not lower it. I'm no expert but I dont think I'd have to cut fuel pressure... I might be wrong ... I'll need a second opinion

Thanks.

 

[rdrkt]

No overall fuel pressure would not be affected by your injectors. However 650s are going to flow a lot more than 550s. To get you’re a/f ratio right again you have two basic options. You can lean it out on the afc or you can turn down the fuel pressure which does the same basic thing.

The B&M is a piece of junk I know this from personal experience. It does not raise the fp at a linear rate with boost especially when you put on a big fuel pump like a walbro of a supra pump. When I put the AEM regulator on my car was noticeably smoother.

 

[Ludachris]

I will likely go with at least 650's when I do upgrade only because if I go with a larger turbo than a 16g, the injectors will be able to handle the fuel supply. Might as well... especially since you'll be able to lean it out with the afc as needed.

 

[L2RTSiAWD]

I have the 650's and I need a FPR bad. I know I'm running really rich and need to turn down the pressure. With any injector bigger than 550 a FPR is a must.

Later,

 

[crankbender]

rdrkt- do you have the bosch part number and a place we can price em?

 

[rdrkt]

You can find them here sorry no part #

 

[crankbender]

how do you know those are bosch and not denso?

 

[rdrkt]

The biggest reason that I know is because I asked. But also I don’t think denso makes injectors in increments of 50 like that. They usually do 660 720 etc and Denso is usually a bit more expensive.