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Underdrive pully

Posted: April 2nd, 2010, 6:28 am
by MazdaRider
Hey guys need help ok so thinking of throwing on an under drive pully to the mx
any one else got one what's the difference??? Is their really one????
An how may belts do u have to change is it just that altonator an the power steering???

Re: Underdrive pully

Posted: April 3rd, 2010, 12:06 am
by Mi|<E
Whats the reasoning behind needing this under drive pulley?

It's alot of money for nil performance gain, unless you like
burning your alternator out more frequently. Your not going
to gain anything over the OEM pulley except more headaches.

Re: Underdrive pully

Posted: December 15th, 2012, 3:22 am
by wednesdayslatest
uhmm.....do you have a listing for the part? i also want to do this i came across an ebay listing

http://www.ebay.com/itm/280836769773?ss ... 1427.l2649

i got the SOHC 1.6 but the listing says it is going to work for mine the seller says its DOHC only BUT the thing is it really does look like the ones i have but im not sure i wanted to see if anyone else would show me the correct part and tell me if this was the right one or not i dont want to have to buy it and return it after

Re: Underdrive pully

Posted: December 15th, 2012, 6:20 pm
by tbondo
Both the power steering and alternator belt need to be shorter.

Re: Underdrive pully

Posted: December 16th, 2012, 3:43 am
by wednesdayslatest
so with this ebay item i need two more belts. do you know or can you show me a listing with the belt i need or a part number idk so i can look it up idc if i have to change the belt i do want the pulley kit though

Re: Underdrive pully

Posted: December 16th, 2012, 10:36 pm
by tbondo
It was quite a few years ago when I put one on my 1.6 but I know both belts had to get shorter. I don't remember or have part numbers but if I remember right I just went to the parts store and found ones that worked.

Re: Underdrive pully

Posted: December 17th, 2012, 12:08 pm
by Josh
You should be able to adjust the slack in the belts. One thing though. the 1.6L are not the best for underdrive pulley. the 1.6 is a small nose crank and already prone to crank failure, Underdrive pulleys tend to speed up this process as they are not balanced properly with your rotating assembly.

if I remember the sohc is V belt and the DOHC is serpentine. It will cause hardly any extra wear on your alt or power steering pump. They are good for about a 5hp gain.

Re: Underdrive pully

Posted: December 18th, 2012, 4:05 am
by wednesdayslatest
Josh wrote:You should be able to adjust the slack in the belts. One thing though. the 1.6L are not the best for underdrive pulley. the 1.6 is a small nose crank and already prone to crank failure, Underdrive pulleys tend to speed up this process as they are not balanced properly with your rotating assembly.

if I remember the sohc is V belt and the DOHC is serpentine. It will cause hardly any extra wear on your alt or power steering pump. They are good for about a 5hp gain.

THANK YOU

and my pulley is already off balance itll wobble sometimes and itll hit the timing belt plastic cover and i got a new one recently im trying to make it last but i will order that part though

they dont make a 1.6L DOHC right? because if not then its deffinitly for a 1.6L engine but the 5HP will be nice with the headers. corksport i got them on sale for 200 bucks instead of 350 plus SH 48dollars i still need to put it in. i got the 110AMP alternator for my amps

is there anything else that i can do to this? (i did just buy a stock clutch because i think mine is going but i could be wrong now its saying coolant temp sensor even though i just replaced it)

Re: Underdrive pully

Posted: December 18th, 2012, 4:06 am
by wednesdayslatest
tbondo wrote:It was quite a few years ago when I put one on my 1.6 but I know both belts had to get shorter. I don't remember or have part numbers but if I remember right I just went to the parts store and found ones that worked.

i am going to try that for sure i thought thatd be my best bet too

Re: Underdrive pully

Posted: December 18th, 2012, 7:58 am
by tbondo
Yes there is a 1.6 dohc. That is what mine was before I swapped in a 2.5. And it is not a serpentine...it is 2 separate belts.

Re: Underdrive pully

Posted: December 18th, 2012, 11:37 am
by Josh
[quote="tbondo"]Yes there is a 1.6 dohc. That is what mine was before I swapped in a 2.5. And it is not a serpentine...it is 2 separate belts.[/quot

This is a serpentine belt below, some call them a ribbed belt. The DOHC 1.6 uses two of them. V belts are just that a V shaped belt.

Image

The pulley wobble is a common issue on the 1.6, more so on the DOHC 1.6. You will have to check your key and keyway to look for wear when you change your pulley. if the edges are rounded I would strongly suggest replacing it. Also I would use lock tight on the pulley bolt.

For more cheep HP a good reference is Solo Miata http://www.solomiata.com/CheapHP.html they share most of the same components. Though if you are changing the clutch you could find a lightweight flywheel to go along with it. I may have a new ACT pressure plate laying around for the SHOC. someone gave it to me like 6 years ago and could never use it.

Re: Underdrive pully

Posted: December 18th, 2012, 3:39 pm
by wednesdayslatest
Josh wrote:
tbondo wrote:Yes there is a 1.6 dohc. That is what mine was before I swapped in a 2.5. And it is not a serpentine...it is 2 separate belts.[/quot

This is a serpentine belt below, some call them a ribbed belt. The DOHC 1.6 uses two of them. V belts are just that a V shaped belt.

Image

The pulley wobble is a common issue on the 1.6, more so on the DOHC 1.6. You will have to check your key and keyway to look for wear when you change your pulley. if the edges are rounded I would strongly suggest replacing it. Also I would use lock tight on the pulley bolt.

For more cheep HP a good reference is Solo Miata http://www.solomiata.com/CheapHP.html they share most of the same components. Though if you are changing the clutch you could find a lightweight flywheel to go along with it. I may have a new ACT pressure plate laying around for the SHOC. someone gave it to me like 6 years ago and could never use it.

well as long as the ebay listing will fit on my car ill be happy just to buy it for now and wait till i get the belts at the autoparts there there is only 3 of them left in the listing and they want 150 OBO i got it to 115....is that a good price for performance pulleys?

its a stock exedy clutch as well i already got it in.....if theres something else like a flywheel i need to change if you got something that would work for me let me know because finding stuff on ebay for rare cars is difficult...i do want to do a swap idk what yet BUT for now i really just want to experience this engine and give it power im going to look at the website right now too thanks

Re: Underdrive pully

Posted: December 18th, 2012, 4:07 pm
by wednesdayslatest
i see that its for the miata but theres a few things if you can help me understand

the first thing thats said costs nothing it has to do with BTDC ...is that my timing belt?

i see that getting a cat back exhaust is good but im going to sleeper status. i dont want to be loud with that car where i live at that car got too much attention so i dont want people looking at it with a loud exhaust eventually ill need to change the cat converter but when that time comes im hoping to put a performance one in there instead of straight pipe....i have a brand new stock muffler on there now so ill wait for that for another year or so once im finally done....who knows i might just swap the motor before i even bother with that one...

i was told i should just keep my flow meter stock...even so i took an adapter and stuck a intake head on it and its attached to the unit itself.....now if i was to replace that unit i believe whatever is plugged into it needs to get plugged into something or else the car wont start at least my friends 92 sohc but i never tried on mine but either way....can you show me a listing of a MAF i can put into mine for more power? ALSO if theres another setup that would be better then mine i wouldnt mind just altering the whole intake

number 5 goes into air fuel ratio i was looking into some kit AEM wideband that is supposed to goto the down pipe of my new headers and it will be connected to a sensor i saw that in my friends car too but if there is a better kit that you can recomend or show me ill look into getting that for later upgrades.....

it also mentions about the 02 sensor....is there a certain one i should be getting? i already got one to put into the new headers because mine is all rusted on my rusted stock headers.....the 02 sensor is a MTE-thomson

ive already replaced the head because my original one cracked then when i put the new head i screwed up bad with the antifreeze and gas lines.....so the gasket had to be replaced....i used a straightedge and the head was perfectly fine so i just dropped a new gasket in and its been alright....other then the fact it feels like it was slipping or something i found out the coolant temp sensor....i found it on the intake manifold green tip....changed it was good for a while but i got a check engine light last night it got a lil bad....i checked it and it still says CTS so im a bit confused since i already put the new part i believe ive replaced all the sensors too....

fuel pressure regulator? i saw on the page it mentioned that...i got one for my car on ebay i went to go put it in then i realized it wouldnt work i got my money back...can you show me a performance regulator for my car?

thanks for helping me thus far

Re: Underdrive pully

Posted: December 18th, 2012, 4:43 pm
by RobMinhas
BTDC is before top dead centre, meaning right before the piston is at top dead centre(highest point of piston travel).

A quiet aftermarket exhaust can be done, Mi|<e(who commented earlier) has a 2.5 inch exhaust on his BPT that's quiet and could be considered sleeperish. Just get a nice resonator in there and it'll help.

Re: Underdrive pully

Posted: December 18th, 2012, 5:14 pm
by wednesdayslatest
damn i made a mistake so you said 1.6L is dohc.....so that must mean this pulley kit will not work for mine? any way you can show me a listing somewhere thats the correct part for mine?