coco95z28

95 z28, a4 stock motor, just some mild boltons... 130k miles


well ok, i put on some under drive pullies (alt. crank)

it ran great for like 2 days, took it out last night to really beat on it, and it starts to break up over 3500-redline, one time i floored it and it went to like 4500 and stopped like i hit the rev limmiter (sound)

NO SES CODES


the other owner "said" the plugs and wires and opti were changed at 85k miles
by a back yard tech. who knows if he did all the plugs and wires.


the question is.................

i dont think the pullies would do it right? btw im bout to take em off anyway didnt do much lol...

also summit has gm opti, or summit opti, or a cap and rotor kit. what one should i go with if i do need an opti? (everyone and their brother keeps telling me its an opti problem................

please help me out before i start throwing parts at my car...

koolaid_kid

The pulleys would not cause a stutter problem. They only provide 5-10 hp, btw.
It does sound like the Opti. IIRC there are diagnostics you can try.
Injuneer and shoebox are experts, listen to what they tell you to do.

coco95z28

yeah thats what i thought, thats why i was leaning toward opti and maybe plugs and wires. i just want to wait till july when i have a week off cause i dought 1 day will do it lol.

anyway, i have an OBD1 scanner tool and im not getting any dtc's in the motor or tranny. although i did manage to somehow turn my fans on high when i was scanning it lol...

Injuneer

And they don't provide anywhere near 10HP on an LT1.

http://www.ws6.com/mod-2.htm

What kind of scanner are you using? The fact you turned on the fans indicates you may have used the wrong one. You need a "real" OBD-I scanner (not the $30 cheapie that shorts the ALDL pins) and an adapter to connect the 12-pin OBD-I cable to the 16-pin OBD-II "style" ALDL connector on the 95.

Courtesy of Shoebox:

http://shbox.com/1/xraycable.jpg

Is it possible your serpentine belt is slipping, and system voltage is dropping into the red at high RPM? That would be the result of the pullies and the wrong belt, or a worn spring tensioner.

Is it possible the belt or some other rotating part is now contacting the plug wires and cutting into them?

I wouldn't assume it's the Opti and start spending money on parts until you try additional diagnostics.

coco95z28

no it says tech1 on the face, and my dad said it was like $2k when the shop bought it.........



good point aout the belt though. the tentioner is new though and it doesnt make an noise?

Injuneer

There are markings on the tensioner assembly with a pointer to show when it is positioned within its correct operating range. Whether it is in that range will depend on whether you selected the correct belt length for the new pullies.

The Tech 1 is the GM/OTC scanner, so it should work. You just need to be sure it has the correct 12-pin/16-pin adapter.

coco95z28

i hope this isnt true but...............


do you really have to bolt up the old pully up the new one? cause i didnt do it.

Injuneer

There are two types of pullies. One is an integral pulley/damper. The only one I'm familiar with is the unit from ASP. Looks just like the stock pulley/damper, with inner and out metal rings connected by a hard rubber ring. That unit totally replaces the stock damper.

The second type is a "sandwich" pulley only. No damper, just a simple pulley that sandwiches between your stock damper and the hub. If you don't put the stock damper back on with this pulley, you are running the risk of damaging your crankshaft with excessive harmonic "whip" every time a cylinder fires.

coco95z28

Auto Specialties 847601

http://www.summitracing.com/parts/ASP-847601/

the kit i have (we had to cut 1/2 inch off bolts so they wouldnt hit opti)



what kit is thats one?

Injuneer

That is only an add-on pulley, not a replacement damper. The reason the bolts are made longer is because they have to fit through both the original pulley/damper and the new pulley. Didn't it come with instructions?

coco95z28

yes. i just re-read them again and it says nothing about bolting the stock one back up.

wont that look kind of dumb though?

also. do you think the car runs bad cause of this?

do you have to put it on backwards or just bold it on the regular way?

koolaid_kid

From ASP website:


"Auto Specialties recommends that these pulleys be installed by a qualified mechanic.

1. Remove alternator pulley nut with impact socket on impact swivel. Remove belt and pulley.

2. Remove three harmonic balancer bolts.

3. Note direction of cast arrow on factory balancer and remove.

4. Install underdrive pulley on crank shaft with countersink in same position as cast arrow. Bolt holes will not gain align if not properly oriented.

5. Reinstall factory onto hub of underdrive crank pulley. Insure cast arrow aligns with countersink. Install bolts using Loctite 242 or equivalent. Torque to 45-50 ft./lbs.

6. Install underdrive alternator pulley. A 1/2" drive impact with 70-80 PSI is required to tighten alternator nut.

7. Install Gates belt K 060598 for part no. 847601. Install Gates belt K060594 for part no. 847600 and install Dayco 5060590 for part no. 847602."

And they claim up to 15 hp. increase, so I was incorrect.

coco95z28

guess i just read it too fast. and no im not a qualified mechanic lol.

so might be a dumb question but.............
do you guys think by leaving off that stock pully is making my car run like crap?


btw 15 hp my @$$. more like 1-2 if you can even feel that

koolaid_kid

I always like the "up to" quotes, because what they actually mean is "you will never see this".
The best thing to do is install it correctly and report back. Eliminating possibilities is the basic path to resolving issues.

Injuneer

Not sure exactly what a technical term like "runs like crap" means, but all you are doing without a harmonic damper is possibly damaging the crank due to torsional twist/harmonics. But I doubt you will feel any loss of performance, and its not going to cause misfires or rough running. Maybe a minor increase in engine vibrations, but I doubt you would feel that.

Are you sure you cut the bolts short enough? Maybe they hit the Opti.