Therx7ist

I have an 88 gxl with 550cc injectors and a newly aqcuired super AFR. My question is.... Is it better for me to keep the 4 550cc injectors and tune them down with the AFR OR Go back to the stock 480cc injectors and tune them up?

Therx7ist

need input

Scott 89t2

what are you mods?? there is no way you will ever need 4x550. maybe put them in the secondarys but you will need to tune them down. you need alot to go past the limit of the stock injectors on an N/A.

scathcart

How about you go back to the stock 460cc injectors (not 480cc), and tune them down?

BlackRx7

why did you upgrade your injectors? if you have many mods you can gain a considerable amount of hp with 550s and a fuel controller, though if the car is stock teh stock 460cc injectors work great and you can lean the engine a little bit in the higher rpms to gain some hp

Therx7ist

my stock injectors were burned in an engine swap fire...I had a set of turbo injectors, so in they went. So the general concensus is that the stockers would be better with an AFR? I'm running racingbeat header and pre silencer and an hks intake with the super afr. Back to (oops) 460's???

scathcart

Stock N/A FC 460 cc injectors will support up to 250 hp. Very few N/A engines make this amount of power. N/A's are tuned pretty rich, like most cars, from the factory, and tuning them down would be worth some power. You could also install the 550's, since you already have them, but count on tuning them WAY down.
What are you going to use to tune your engine? IE: what method of getting an accurate A:F?
Sean Cathcart

Therx7ist

I need to get it tuned at a shop. But I need to know which setup would be better for when I do get it dyno'd. I have 550's all around. Should I go back to 460's all around or leave the 550's or go 460 primaries and 550 secondaries? What will acheive the best result with an intake and a header presilencer combo?

scathcart

I'm not too familiar with the S-AFC, having no first hand knowledge, but IIRC correctly, it was able to tune down 550's to an acceptable level under all driving conditions. You have the 550's, so use them, but the stock 460's would have been MORE than ample for your limited upgrades.

550's are for bridgeported and up NA's. Just expect to WAY tune down those suckers.

Therx7ist

BUMP....Anymore suggestions?

Therx7ist

Can anyone recommend a good shop in new york?

Therx7ist

bump

NZConvertible

Putting larger injectors in won’t make any power. Airflow makes power, not fuel flow. If you run four 550’s with a –16% correction across the board, it’ll run exactly the same as is you had four 460’s in there. It’s the altering of the A/F ratios that will gain you a little power, by leaning out the factory’s very rich mixtures.

Rpeck

ooops wrong post

Therx7ist

To what extent do most people lean out the mixture? Leaner at lower rpms or higher?

Therx7ist

?

NZConvertible

You find that out on the dyno.

Josepi

Actually, tuning the stock injectors down would be easier than swapping in 550's and doing the same. Most have luck from 3-5.5K.

Therx7ist

what?