LT1 Underdrive pulley: gain? problems?
Thread Starter
Safety Car
Joined: Sep 2002
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From: Maryland
LT1 Underdrive pulley: gain? problems?
Who here has actually done this mod? Do have dyno numbers or ET's?
Did you have any ill effects: how's the power steering? Does the alternator
charge unless at idle with headlights on?
--I have my car in the shop already for heads/cam, now would be the time
for me if I'm going to do this.
Did you have any ill effects: how's the power steering? Does the alternator
charge unless at idle with headlights on?
--I have my car in the shop already for heads/cam, now would be the time
for me if I'm going to do this.
Racer
Joined: Jul 2002
Posts: 447
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From: Malta Europe
Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
Some of us here had done them and loving them with the results but some of us had some charging issues , I know I did !!! when I leave it idle the battery will go flat !! But as far as 1/4 mile times I read that they can shave about .2 of your E.T`s
Good luck
Good luck
Thread Starter
Safety Car
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From: Maryland
Re: LT1 Underdrive pulley: gain? problems? (marlon88)
Marlon,
Thanks for your reply. 0.2 S is a lot, was that for the LT1? I looked up
old threads here and there is agreement on the L98 but not on the LT1.
This battery draining: how much idling did it take to kill your bat? was it
a new bat? Were your headlights on? Were you running a big stereo?
--I don't usually get caught in traffic jams at night and have the factory
cassette only. But, if it drains at idle in 1/2 or so, that would be bad!
Thanks for your reply. 0.2 S is a lot, was that for the LT1? I looked up
old threads here and there is agreement on the L98 but not on the LT1.
This battery draining: how much idling did it take to kill your bat? was it
a new bat? Were your headlights on? Were you running a big stereo?
--I don't usually get caught in traffic jams at night and have the factory
cassette only. But, if it drains at idle in 1/2 or so, that would be bad!
Racer
Joined: Jul 2002
Posts: 447
Likes: 0
From: Malta Europe
Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
That was all on my 88 L-98 ,but I don`t see why It dont help the LT-1 :confused: recently I replaced the pulleys with the stock ones and now I can leave it idle for hours with out any problems !!! before It left me srandet several times , but one time at night I left it idle with every thing off no lights no noting , and left it for about 10 mins in idle , then I went and shut her off becouse my friends insisted for me to stay .. when I was going , I tryed to start it and click click the volts was about 10v and that was a new battery too !! luckly I wasn`t too far from home and I went for the jump leads and then she started with no problems !!! that night I was so mad that I took them off and made the factory ones back in , ever since No problems !!! And even me I have to stock Bose casette system .
My friend who is a mechanic told me that If you want to go fast there is a bunch of things to do and forget about the pulleys !!!
Hopefully some one will chime in and tell us a bit better about the pulleys because some of us here don`t have any problems !!!
Good luck
:seeya
[Modified by marlon88, 2:16 AM 5/6/2003]
My friend who is a mechanic told me that If you want to go fast there is a bunch of things to do and forget about the pulleys !!!
Hopefully some one will chime in and tell us a bit better about the pulleys because some of us here don`t have any problems !!!
Good luck
:seeya
[Modified by marlon88, 2:16 AM 5/6/2003]
Safety Car
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From: Southern California
Re: LT1 Underdrive pulley: gain? problems? (marlon88)
I have an asp pulley and belt that i'm selling. I don't want to install it since I need to convert my double sided belt ('92-'93 LT1) into the '94-'96 LT1 single sided design. Too much money for my blood. Let me know if your interested. I'm asking $100 shipped. I have pictures too.
raysur@usa.com
raysur@usa.com
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Joined: Aug 2002
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From: Kentucky
Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
You can get the pulley kit with a smaller alternator pulley to keep up the charging. You'll still have a smaller crank pulley and it'll still turn the ac and steering pump slower.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
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From: Toronto ONTARIO
Re: LT1 Underdrive pulley: gain? problems? (hngacurv)
I have used both the march and asp for the LT motors. Both pulleys allow the car to idle forever. without the alternator pulley i notice only at night when the headlights are on the the interior lights are dimmer... which is annoying to me. I also have a high powered deck /amp as well so thats a reason too. Theyre worth the $$.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
Re: LT1 Underdrive pulley: gain? problems? (Raysur)
I have an asp pulley and belt that i'm selling. I don't want to install it since I need to convert my double sided belt ('92-'93 LT1) into the '94-'96 LT1 single sided design. Too much money for my blood. Let me know if your interested. I'm asking $100 shipped. I have pictures too.
raysur@usa.com
raysur@usa.com
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Race Director
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Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
I would really be concerned about the charging system. A friend of mine was at the track the other night and we data logged his car. At WOT he never put out more than 12.5 volts. Meanwhile mine put out 14.5 all night long.
I do have a hard time believing that his car doesn't put out at WOT what mine does at idle but he does have some charging issues. Maybe it's a weaker alternator (93 Z-28) to begin with, maybe his is on it's last legs?
I do have a hard time believing that his car doesn't put out at WOT what mine does at idle but he does have some charging issues. Maybe it's a weaker alternator (93 Z-28) to begin with, maybe his is on it's last legs?
Thread Starter
Safety Car
Joined: Sep 2002
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From: Maryland
Re: LT1 Underdrive pulley: gain? problems? (Nathan Plemons)
Nathan,
I went to your website and noticed that underdrive pulleys are not listed
under either your current or future mod list. Do you know what the gain
would be on the LT1, and what parts I would need with the 1993?
I went to your website and noticed that underdrive pulleys are not listed
under either your current or future mod list. Do you know what the gain
would be on the LT1, and what parts I would need with the 1993?
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
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From: Maryland
Re: LT1 Underdrive pulley: gain? problems? (DieL)
Die,
What performance gain did you get? When you said the lights dimmed,
that was with the underdrive alt. pulley set, right? I could do just the
crank but I don't know what the benefit would be...
What performance gain did you get? When you said the lights dimmed,
that was with the underdrive alt. pulley set, right? I could do just the
crank but I don't know what the benefit would be...
Race Director
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Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
Nathan,
I went to your website and noticed that underdrive pulleys are not listed
under either your current or future mod list. Do you know what the gain
would be on the LT1, and what parts I would need with the 1993?
I went to your website and noticed that underdrive pulleys are not listed
under either your current or future mod list. Do you know what the gain
would be on the LT1, and what parts I would need with the 1993?
That alone does not make it impossible, but you would need to replace the tensioner and the power steering pulley with the ones designed for a single sided belt.
On another note, of interest. Jegs actually sells a replacement SFI certified balancer for the LT1 now, they also sell an underdrive version. This has interested me slightly, if I do go with an underdrive setup I would probably do it that way.
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
Die,
What performance gain did you get? When you said the lights dimmed,
that was with the underdrive alt. pulley set, right? I could do just the
crank but I don't know what the benefit would be...
What performance gain did you get? When you said the lights dimmed,
that was with the underdrive alt. pulley set, right? I could do just the
crank but I don't know what the benefit would be...
it ran a consistent 109.7 mph. When my car was stock it ran consistent 100-102 mph. a 8-10 mph increase shows (dare i say it), by the numbers i may add, that theres an 80-100 hp increase. i did the mods 1 by one and my car went from 107.5 avg mph to 109.7 and a few 110s the week after the install.
:cheers:
Safety Car
Joined: Jun 1999
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From: Southern California
Re: LT1 Underdrive pulley: gain? problems? (DieL)
Diel,
I don't take offense to YOU calling me sorry. :rolleyes:
I don't put junkyard parts on my car. I have standards. The pieces new were over $100. I'd rather spend $2XX on other mods. Do you have a problem with this?
I don't take offense to YOU calling me sorry. :rolleyes:
I don't put junkyard parts on my car. I have standards. The pieces new were over $100. I'd rather spend $2XX on other mods. Do you have a problem with this?
Melting Slicks
Joined: Mar 2003
Posts: 2,472
Likes: 0
From: Toronto ONTARIO
Re: LT1 Underdrive pulley: gain? problems? (Raysur)
Diel,
I don't take offense to YOU calling me sorry. :rolleyes:
I don't put junkyard parts on my car. I have standards. The pieces new were over $100. I'd rather spend $2XX on other mods. Do you have a problem with this?
I don't take offense to YOU calling me sorry. :rolleyes:
I don't put junkyard parts on my car. I have standards. The pieces new were over $100. I'd rather spend $2XX on other mods. Do you have a problem with this?
:cheers: :cheers:
Safety Car
Joined: Jun 1999
Posts: 3,641
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From: Southern California
Re: LT1 Underdrive pulley: gain? problems? (DieL)
DieL,
My car ('92-'93) needs the idler assembly from the '94-'96 as well. This is a moving piece with bearings and a spring tensioner. This is the object I wouldn't buy used.:smash: Do you see my point now? :banghead:
sothpaw2,
I'm sorry for taking up your post. I recently saw a somewhat stock LS1 Camaro in Hot Rod magazine get 9.x rwhp and even more torque from just the pulley. Doing the pulley isn't for me right now.
[Modified by Raysur, 9:49 PM 5/6/2003]
My car ('92-'93) needs the idler assembly from the '94-'96 as well. This is a moving piece with bearings and a spring tensioner. This is the object I wouldn't buy used.:smash: Do you see my point now? :banghead:
sothpaw2,
I'm sorry for taking up your post. I recently saw a somewhat stock LS1 Camaro in Hot Rod magazine get 9.x rwhp and even more torque from just the pulley. Doing the pulley isn't for me right now.
[Modified by Raysur, 9:49 PM 5/6/2003]
Melting Slicks
Joined: Mar 2003
Posts: 2,472
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From: Toronto ONTARIO
Re: LT1 Underdrive pulley: gain? problems? (Raysur)
the moving tensioner...... once a car is started from new they all do the same thing, rotate. not like they could be tweaked for power or anything or tampered with. to me they would be pretty much the same new or used... unless i really look into the piece which i have to admit i havn't.
the way i look at this is like someone who buys headers.. and doesn't want to install them because he/she doesnt want to change the header gaskets!
sothpaw2 : remember the LT1 vette and camaro use completely different pulleys. The underdrive ratios are different as well. On the camaro they bolt on in front of the balancer. On the vette they are 1 piece, which explains the cost difference. I have had positive experiences with both MArch and ASp although i have to admit the quality of the asp is much better. Add to that longer lasting accessories and some power and you cant go wrong........ unless of course .........you need a tensioner pulley.... :rofl:
:cheers:
the way i look at this is like someone who buys headers.. and doesn't want to install them because he/she doesnt want to change the header gaskets!
sothpaw2 : remember the LT1 vette and camaro use completely different pulleys. The underdrive ratios are different as well. On the camaro they bolt on in front of the balancer. On the vette they are 1 piece, which explains the cost difference. I have had positive experiences with both MArch and ASp although i have to admit the quality of the asp is much better. Add to that longer lasting accessories and some power and you cant go wrong........ unless of course .........you need a tensioner pulley.... :rofl:
:cheers:
Melting Slicks
Joined: Jan 2000
Posts: 3,418
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From: NW Chicago Suburbs
Re: LT1 Underdrive pulley: gain? problems? (sothpaw2)
The LT1/4 H2O pump is driven by the cam chain, the L98 H2O pump is driven by the crank pulley. There's a lot more HP to be had by swapping pullies on an L98 than an LT1.
The alternator's engine load is adjusted by the alternator voltage regulator to match the instantanous needs to the car, the H2O pump just spins away no matter how much cooling is required.
If you want to make HP this way on an LT1/4, you'll need to switch to an electric H2O pump.
Eric
The alternator's engine load is adjusted by the alternator voltage regulator to match the instantanous needs to the car, the H2O pump just spins away no matter how much cooling is required.
If you want to make HP this way on an LT1/4, you'll need to switch to an electric H2O pump.
Eric
Thread Starter
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From: Maryland
Re: LT1 Underdrive pulley: gain? problems? (DieL)
DieL,
What was your car? Your sig. indicates a 2002 C5. I'm interested in
seeing if this mod would work on a vette LT1 motor. I don't know if the
LS1 has a cam driven water pump, but that the LT1 does and that makes
the gain less than for a Mustang.
I have a 1993 car, so I am in the same boat as Ray. I am really confused
as to what I would need if I elected to go with this mod...
What was your car? Your sig. indicates a 2002 C5. I'm interested in
seeing if this mod would work on a vette LT1 motor. I don't know if the
LS1 has a cam driven water pump, but that the LT1 does and that makes
the gain less than for a Mustang.
I have a 1993 car, so I am in the same boat as Ray. I am really confused
as to what I would need if I elected to go with this mod...