Modded 86 Slower than V6
 

Here is a run down of the Mods I was told were done:

bored out 30 thousands
Motorsport roller cam & roller lifters (282 duration, 498 lift)
complete head rebuild (shaved 10 thousands)
stock headers (They are not, they look like long pipes)
Flowmaster exhaust with H Pipe no cats
Hypertech chip
K&N drop in air filter
World Class T5

In the paperwork I recieved I found some info.

Grind Number M-6250-E303
Rocker Arm Ratio: 1.60
Max Lift Intake and Exhaust 110 for both
Cam Lift .311 (Int and Exh)
Valve Lift .498 (Int and Exh)
Cam Timing @ .004 Tappet Lift:
Intake Opens 28 BTDC Closes 74 ABDC Dur 282
Exhaust Opens 68 BBDC Closes 34 ATDC Dur 282
Cam Timing @ .050 Tappet lift:
Intake Opens 0 BTDC Closes 40 ABDC Dur 220
Exhaust Opens 40 BBDC Closes 0 ATDC Dur 220

The car is SLOW, I thought so before but have been driving faster cars and thought maybe my memory was off. Today on the way home a ratty Neon with dual exhaust and fart cans was lined up at the light, I could just barely beat him and his exhaust smoked at each take off like the rings were shot.

The car sounds good, but never seems to kick down or throw you back at all.

For now I just want to get it running right, (at least as fast as stock) after awhile I can look into other mods.

It also idles between 1000 and 1500, I mean it goes up and down. Also while driving if the RPM's are below 2000, the car kind of jerks or surges.

Any ideas what to check? It sounds like Speed Density problems from what I read. Also how do I know what fuel injectors I have? Mine look yellow or orange. (I'm truly "color deficient" I can see colors but varying shades of the same color look the same)

Thanks,
__________________
Sam Woodson
Harvest, AL
1986 Mustang GT Convertible 5spd

Re: Modded 86 Slower than V6
 

Well the Fox body convertibles are pretty heavy and you have E6 heads I believe which suck even worse than E7's that come on 87-93 mustangs.

The surging and high idle is probably the speed density ECU not liking the E303 cam. Get a fuel pressure regulator and set the fuel pressure, set the TPS voltage and make sure your car is set at 10 degrees initial timing since you have a chip. You may want to also do a compression to test to determine the health of your engine.

The cam isnt helping at all with the parts you have so other than the exhaust your car is pretty much stock.

I wouldnt expect a basicly stock 1986GT convertible to be very fast, at least not until you get some real mods.

I used to have a 1988 GT convertible 5 speed and it ran a 15.40 @88mph bone stock which isnt very fast.

BTW: the yellow injectors are the stock 19#ers.

Good luck,

Re: Modded 86 Slower than V6
 

Did the 86 have the lame flatop pistons dark5.0? I cant remember, but with the heads shaved and an e-cam the clearance is too close, and will cause problems.

Almost sounds like your describing a neon srt-4? if so those things are pretty quick, if it wasnt, then dont ever race one until you get your problems figured out.
I would dyno it, a guy in the dyno shop could probaly point you in the right direction. if you do have 86 heads then get rid of them if you want to see any power.

Re: Modded 86 Slower than V6
 

It wasn't a SRT-4 maybe an SXT

As far as clearance goes, it's been running since 2000 like this, about 30k miles. Per the PO

Others are telling me to go MASS Air, the Speed Density can't handle this cam, not enough Vacum. SD would be cheaper and easier than going to a new cam and would be beneficial down the road. That's the way I'm leaning for now, unless someone has a reason not to.

Thanks,

Re: Modded 86 Slower than V6
 

Well I can tell you this. I had an E303, ported stock heads and a ported cobra intake and had my 88GT convertible running like a top with speed density.

On the other had I much prefer mass air.

Re: Modded 86 Slower than V6
 

I knew a guy with an 85 coupe, he drove the car for a while before he tore down the motor to find out the pistons were hitting the valves at times,(had nos) there was no noise.
Im not saying you have this problem, just saying you might not always know right away if your making contact with the valves.

On another note, no one mentioned the gear situation?
do you have 2.73's?
if so, throw some 4.10's in that thing!!!:D an e-cam + 2.73 gears = a ricer leaving you in the dust.
that cam needs at least a 3.55 gear to make up for the lowend loss, it will feel like a dog otherwise.

Re: Modded 86 Slower than V6
 

It has the 2.73 rear end with the World Class T5 that is geared better, but it really runs out of breath. I wonder what the computer is doing to make it so slow. The 86 had limited things to control. The PO said he advanced the timing as much as he could for better performance, but it's severely lacking in power.

Re: Modded 86 Slower than V6
 

i hate to reiterate what coupe50h said but i think it is necassary in this case. you absolutely need gears. i am currently running an ecam with edelbrock heads, but before that i was running the car with ported e7's and it ran high 13's all day and night (with 3.73) gears. my buddy had a similar setup and he was only running 273's. his car didn't stand a chance. to really hammer this point home, another friend with similar setup has 4.10's and still can't catch him. DON'T FEAR THE GEAR!

Re: Modded 86 Slower than V6
 

In this case even a 3.27 gear would help, i ran these for a while with the e-cam, I made up for the lack of gear with a 5k launch on slicks:D

Other than that, a dyno session is necessary to see what rpm it's falling on it's face at, then figure out why?
Some dyno shops can tell you whats wrong, right away by how the power curve looks, and compared with the a/f ratio.
good luck.