I just put an turboII AFM and sec. injectors on my mildy modded N/A, what a difference my car now pulls smoothly to 8100 and it seems to have a little more power. I am taking it out to the track this fri. to see how much faster it will be. My 86 N/A has RB header. intake, apexi n1 , and rb pullies.

 

with those minor mods, the bigger injectors on the secondaires will probably result in lower overall HP unless you have some sort of controller for them such as a AFC.

In addition, there is no real HP after 6500 on a S4 N/A motor despite any mods you may have made unless you are using a S5 or custom intake runners, and/or have ported the motor.

Also remember that the stock flywheel is too heavy to run very long at much more than 8000 RPM with exploding.

 

NAs run rich at the high end, so there is no need for additional fuel until you get into some serious porting. Also, the TII AFM is the same as the NA unit, with some minor spring changes. It will cause the car to run much richer throughout the RPM range.

Put the car back the way it was and you'll be much better off.

 

I think that something was wrong with my stock secondary inj. so i had a set of turboII lying around. I am going to the track this fri. and if it is not any quicker than i will switch. I am only at 8000 for a few seconds and have had over 200 passes a the track with no problems with the flywheel. From the seat of my pants testing it seems a lot smoother all the way up to 8,000.
Thanks for the info guys.

 

Clean your injectors or get new ones. THey aren't expensive at all. YOu will likely never use the FULL potential of the 550s that you have on there. The 460's are capable of 247bhp according to how much they can flow.

Santiago

BTW I don't think I have seen a dyno sheet of a 200~ WHP N/a that was anything less than bridge ported. So NO you will not need them for a while

 

Yea but it is running very well now, i was hitting 9.8-10.0 in the 1/8 mile now it should be 9.5.-9.6. We will see on fri. when i hit the track.

 

The S5 AFM is calibrated for the injectors. The fuel maps are the same between n/a and TII's on S5 cars. Im currently running a TII AFM and 550's all around, and it runs identically to runnign the 460's and n/a AFM, except that I have the extra range of the TII AFM now.

But, your car is a S4, and that doesnt apply. The S4 AFM's are interchangable. The fuel maps are NOT the same for TII and n/a. All youre doing is running EVEN richer above 3800 rpm than most are. Its not making more power.

 

Well I hit the track on friday, it was a little misty out so my 60' were pretty bad, but i did pick up a few mph on the top end. Before it would only hit 69-70 mph and now i get 72-73 mph in the 1/8 mile.

 

9.6 in the 1/8 mile does NOT justify bigger injectors. A good running n/a with exhaust and intake will run that or better all day long with intake and exhaust. I ran a 9.9 @ 74 with a 2.4 60 ft time with ONLY full exhaust in my GTU.

 

Yea i Know but i was running way to lean (problem with my sec. inj) So i had a few sets of the turbo inj. lying around (free) and put them in the secondary's. I have a safc at the shop so i'll probably put that in and just trim it down a little. Thanks For the input. Nice times for your 7, the N/A guys around here run in between 10.2-10.5 with intake and a cat back on stock ports.
Chris