I recently had my car dyno'd and found something very disturbing, and I'm hoping to get some opinions on what I should do at this point.

Before I decided posted this, I did some research and found some very good info regarding AFR when running Super Chargers.

https://www.s2ki.com/forums/index.php?showt...0&#entry9038081

https://www.s2ki.com/forums/index.php?showt...&#entry13304767

However, based on what I'm reading, it seems that the Comptech FRP is a plug and prey solution. It works for some, but not for others.

And based on my dyno's, I don't belief it is working for me.

Some background:

Back in 2003, my car had the CTSC w/o AC (not out yet), on 7 psi. The car was dyno'd and fuel tuned. Made about 325hp and 200tq on the Mustang Dyno. Other mods at the time: Bored TB, TP, header, and Apxi N1 single.



Fast forward to today (no dyno since 2003), I've added the Aftercooler, switched the exhaust to Fujitsubo Dual, and some other none engine related mods.

Here is the first dyno:



As you can see, I've lost a lot of HP and TQ, due to the fact that my car was running very, very lean. The guys at the shop suspect that it was caused by the addition of the Aftercooler.

I was kind of surprised because, when I first ordered the AC from Comptech directly, I had asked one of their Techs regarding the need to get the car re-tuned. And I was told it wasn't necessary, and if anything, the car should actually be running safer than w/o the AC. And that was back in 2004. So its a very scary thought that I've been running this lean for the last 4 years w/o knowing. I've driven my car pretty hard through the years, and spend lots of time up in the Vtec land. They thought my motor should have blown by now. /knock on wood.

So after some easy pulls on the Dyno, we re-tuned the FPR, and got it down to a much more manageable state, and here is what we ended up with:



Overall lay:



As you can see, after 5 years with the SC, and 4 years of running lean, the car responded immediately just by giving it more fuel, and its almost back to its oldself from 4 years back in terms of HP and TQ. But, it is still running lean for a supercharged car. The techs told me I'm pretty much maxing out the FPR, and they don't think they can crank it up any higher.

They suggest I go Stand alone like AEM, but for now, I don't have the funds to do this, and if I did go with AEM, I want to go further with the SC, like running 10 psi, injectors, and fuel pump. So this will not be a solution for me in the near future.

Is there anything else I could do at this point? I've been taking it real easy on the car, but I would love to be able to get my AFR down to around 12 at least to feel safer about driving the car hard again.

Also, is there anyone else out there that is in the same boat as me? i.e. Had the S/C, then added the AfterCooler later on? If so, I recommend you to get your AFR checked out, and make sure you're not running lean either.

 

Yep makes perfect sense.

You added a aftercooler. You Mass charge increased due to the drop in temps you AFR was set for a non intercooled setup. Density of air goes up and the fuel added does not = lean. I hope no one has just popped a intercooler on and not looked at there AF ratios... glad you did! This is assuming that you decreased your pulley size to get back to the PSI you were previously running btw.

 

It looks like you're still really lean, do you know how your fuel pressure is? I'd almost wonder if there's an issue with the wideband the shop used since if you were driving around that lean for 4 years I wouldn't suspect your motor would be running today.

 

Nope. Actually, I'm still running the exact same pulley from 2003.

I didn't get much drop in PSI at all with the AfterCooler. I've also added a High Flow Cat back in my car during that same Dyno Session, and my boost with the CAT read 6.9 PSI, which was pretty damn good considering.

 

Thats a good question. Unfortunately, I do not have a Fuel pressure gauge, so we just tuned it according to the read out from the Dyno.

I do not know if there was an issue with the wide band at the shop though. However, I don't think there is, since after the fuel tune, I've gain back most of the power I've lost since the installing of the After Cooler.

Is that what they mean by Honda motors being bullet proof?

 

Um Yikes... did I see 14.9 AF Ratio? under boost? Ah... well if that AF sensor is right that is WAAAAAAY to lean under boost. It will make great power until it burns down to the compression ring landings eventually. Make sure there isnt something wrong with his sensor because I would never ever run a boosted setup with N/A AF ratios (just me but does anyone else see a problem with his AF ratio during the run? They are all over the place!!)

 

I agree, cant see that motor lasting 3 years while running those kind of AFR numbers. I think the gauge was off, or possibly not far enough up the tailpipe? I'm far from an expert but there's some basic concepts that seem to be not right here.

 

I have the same set up and also found there to be fuel delivery problems at first. Also I do agree that 14.9 afr is confusing. I'd say this wasn't accurate. I run a wideband on my set up and before getting my fuel delivery problem worked out it was running this high and believe me, you will not make any power, that car will fall on its face when boost comes in. I have found 12.5 to pull the hardest with my car.

My fuel delivery problem came from the stock fuel pump, you need a high flow pump and you also need to crank the fpr down almost all the way to the nut, just about 5 mm from flush. The car needs to run at 95 psi wot to get down to 12.1 afr at 5.5 psi which is possible with the stock fuel injectors and stock ctac kit. I don't know how your getting 6.9 psi. You would not be the typical. If you are indeed getting this psi then you may indeed be at the point of needed a stand alone. The typical is my situation however. If you don't have a high flow fuel pump yet, I would get this and see what happens first before spending $$ on a stand alone set up. Good luck.

 

do you still have the HFC on your car? any kind of cat will skew results on the lean side, for obvious reasons. did you try reading AFR ratios from the OTHER tip on the exhaust? one side can sometimes flow better than the other... i dont know much about the fuji exhausts, but i do know that some baffle/muffler systems can skew the afr reading as well....

those AFRs just look inaccurate to me. the reason the comptech tech said that your car should run safer with the A/C is because most guys that add a cooler lose a bit of boost. less boost = less air = richer mixture.

you mentioned up top that they recommend you go with a standalone. you responded by saying you would want to do it correctly with a smaller pulley, bigger injectors, and an UPGRADED FUEL PUMP - does that mean you're still running around with the stock fuel pump?

also - 7psi on a non a/c setup is too much boost for the stock pulley, if i am not mistaken. i thought the stock kits made 5.5psi? i made 6.5 but i was accidentally using an ap2 pulley on my ap1. regardless, my afr's were lower than that, and i was reading through a cat!

 

Not to hi jack, but does anyone have an ap2 pulley for sale? I'd like to maximize my stock CT set up. Pm me if you do, thanks.