Low on power, wrong series of parts used together?

90tbirdsc

Registered User
ok guys, Im having some issue with my sc. Ive been told that Ive been expecting to much from it and im now im disappointed with the outcome but that is not the issue, I have something going on that me or my friends or my dad can figure out. So im going to in detail describe my setup and see if anyone sees a problem with it. Then ill describe a couple other things. Here goes:

The factory exhaust manifolds have been ported, I have 2.5 downpipes right off of the manifolds, they are the good mandrel bent ones (not the ones that the bends push in but are still smooth) they are very good flowing. Those go into a SCP resonator that is dual 2.5 in and single 3 exit, after the exit there is a pipe with a 45 degree bend and then the exhaust dumps. that's it for exhaust. Next is the intake, the filter is down in front of the front tire out of the engine bay, its clamped on a 4in pipe that feeds my LMAF, after the MAF is a 3.5-3 reducer and a 3in intake that goes to a 75mm Precision products TB and a magnum powers inlet and a ported late model with coated rotors that will peg the gauge at 10% OD, 3/4 raised top and then 2.75 FMIC pipeing, that goes into a 31x11x3 ic. the piping all has gradual bends and im using silicone couplers and t-bolt clamps on the sections that are not TIG weded together. im still using the factory return plenum and lower pipe. motor is all stock internals. I have a 255lph walbro fuel pump and 42# injectors. my wideband shows that im not short on fuel cause with my not perfect current tune it is 10.9-11.5 depending on the day. I have autolite xp 103 spark plugs gapped to .035 with screamin deamon coil pack and livewire wires.

the timing will randomly pull back to 12 degrees or 18 degrees but there is no difference in power no matter what it pulls back to which is confusing:confused:

from all my research ive done a setup like this shouldn't have a problem running low 14's or mid-upper 13's. but racing a car that is a consistent 13.6 I got walked on very badly (like I knew I would) like I might be able to run a low 15.:(

I have a starter tune from DD and me and him have improved it through email over the past week or 2

Also my supercharger is very quiet, I cant hear it over my exhaust and no one else can hear it outside/in front of my car/ down the road either.

anyone have any ideas? all help is appreciated.
 
Last edited:
Im not so sure youde be running anything better then a mid 14 You would get walked on by a 13.6 car...Thats what im thinking in an ideal situation. You may be getting some knock that is pulling your timing. pegging gague id say too much bost..lost power due to pulled timing..STILL...nowhere near a 13.6 car IMO
 
Im not so sure youde be running anything better then a mid 14 You would get walked on by a 13.6 car...Thats what im thinking in an ideal situation. You may be getting some knock that is pulling your timing. pegging gague id say too much bost..lost power due to pulled timing..STILL...nowhere near a 13.6 car IMO

I know it isint near a 13.6 car. if It was I would be happy and not posting about my issue on here.;)

but between 12 degrees and 18 degrees there should be a noticeable power difference correct?

but there isint, that's why its confusing me on that part
 
Last edited:
I know when my car was knocking It wasnt observable but was doing something to the extent that your car is. Pretty much when you get timing pulled its going to be doggy be it 12 or 18 an dteh difference may not be noticable. But see what Dave says he has much more experience tuning
 
I know when my car was knocking It wasnt observable but was doing something to the extent that your car is. Pretty much when you get timing pulled its going to be doggy be it 12 or 18 an dteh difference may not be noticable. But see what Dave says he has much more experience tuning

he hasint answered my emails after he said its pretty much ok and I was expecting to much from it and he is making 280rwhp with a similar setup. but I know something isint right with my setup cause it isint running good at all.

he said something about disableing or removing the knock sensor, I cant remember off the bat but didn't talk much about it

im thinking just put in some vp110 and see if it still pulls timing and or runs good while modifying the tune to keep the AFR right? Or could it be a internal motor issue from running 20% OD on a stock IC and early model?
 
Last edited:
he hasint answered my emails after he said its pretty much ok and I was expecting to much from it and he is making 280rwhp with a similar setup. but I know something isint right with my setup cause it isint running good at all.

he said something about disableing or removing the knock sensor, I cant remember off the bat but didn't talk much about it

im thinking just put in some vp110 and see if it still pulls timing and or runs good while modifying the tune to keep the AFR right? Or could it be a internal motor issue from running 20% OD on a stock IC and early model?

There are a lot of things that can be contributing to your results. In my case I turned off the knock sensor and set it to 16 deg max. Putting in race fuel won't necessarily help anything because your combo doesn't require race fuel.

Your blower being "quiet" as you say doesn't really speak to anything. A stock 94 blower isn't loud, and while you say it is ported, that can mean a whole bunch of different things from good to bad. A lot of people around here think they can port blowers. Very few actually know what they are doing. Some do more harm than good.

I also don't rely on your statements of "AFR in the 11.5-11.0 range" because that doesn't say under what conditions when, or how accurate that that observation was. You should be datalogging AFR in BE so that people can see what you are observing. It also doesn't hurt to have your wide band checked against a dyno. Cheap WB02 kits are notorious for being inaccurate. Yes, all generally available wide band kits are "cheap" by definition.

Don't overlook other things, like a slipping tranny or other possible issues too. Internal engine issues are possible. Have you checked compression? What do your plugs look like, and what plugs are they? This is all basic stuff that you have to cover.

As for being walked by a 13.6 car, yes that's sad but I think that the whole thing needs more looking into. A 14.0 car will get pulled by a 13.6 car, but not so that you wonder if your gas pedal is working. It would be close.

With your mods a 14.0 isn't an unreasonable target to shoot for. I put together a car for a customer of mine that ran 14.1 @ 100 mph on street tires with basically the same setup you have. He had a similar FMIC, late model blower (unported), 5% pulley, stock inlet, 70MM TB and CAI, full exhaust (with cats). We didn't dyno tune the car at all, just a baseline tune so I don't know how much power it made, but I figure it was probably 260rwhp or so.
 
It's not moving any air. Your boost gauge is lying to you.

Ok, so then how was I pulling a 200% load at 20% OD? I don't quite understand the load percentage thing?

Do you think it's a issue with the supercharger or something else?
 
One thing I notice is the ACTs never move even at WOT, if that blower was working hard at 10% OD those temps would be moving I would think.

Your battery voltage also looks low to me at 11v.
 
Ok, so then how was I pulling a 200% load at 20% OD? I don't quite understand the load percentage thing?

Do you think it's a issue with the supercharger or something else?

Ok, just looked a little closer and realized that it's running dead lean, not the 11.0-11.5 that you said. Time to go back to the original tune and start over.
 
One thing I notice is the ACTs never move even at WOT, if that blower was working hard at 10% OD those temps would be moving I would think.

Your battery voltage also looks low to me at 11v.

That makes sense, do you believe it to be the porting or something else? and yes the voltage is low. My alternator went out on me.
 
Could also be the fact that the car is an AOD. Going from a 16.4~ to a 15.0 is not bad at all with that mod list. I was down this path once before.
 
I cant see afr so idk whats up there. Dalke says its lean then its lean. Its a pig for sure tho, 15-60mph takes like 8 seconds according to the log:eek:.
 
I cant see afr so idk whats up there. Dalke says its lean then its lean. Its a pig for sure tho, 15-60mph takes like 8 seconds according to the log:eek:.

yea, something isint right. Im building a 3.5 intake instead of my 3in. don't think that will make much difference but I figured ill try it and see.

im also going to un-plug my knock sensor and set timing to 16 degrees
 
Back
Top