ok chaps, i should have a pettit sub frame on the way for my 20bFD conversion soon. what are others with this setup using for motor mounts, and what mounts are the correct ones? FC? FD? do i keep the stock mount brackets, or is it converted to the FD ones?

i dont want to use solid mounts because of the vibration.... so i guess all that is left is stock rubber, or the stiffer urethane. im wondering what other people deceided on using. thanks much. -heath

 

I used Mazdaspeed FC mounts, Just trimmed the metal on the mount for clearance. You still use the 20b brackets not the fd ones.

 

so i should be buying FC mounts? i called pettit today and they told me FD mounts?? whats the difference between the FC and FD mounts? are teh FC ones shorter? i know the pettit frame gets the UIM pretty damn close to the hood. thanks, heath

 

Would the rubber mounts that came with your 20b work?

 

If i remember right the Mazdaspeed FC mounts were 1/8" shorter. Plus they are alot less expensive.

My motor didn't come with the 20b rubber mounts, so i couldn't compare.

 

Here are FC mounts from FC3S.org. I'm considering using these unless someone knows a reason not to.

$250

 

ok sorry im so confused with the mount issue. ok im trying to understand how everything fits together because my motor is currently 75mi away . ok here are the questions which i still am not sure i have the answers to.

1) i know the cosmo 20b does NOT use the same brackets as the FD.... BUT, are they the same brackets as the FC, or a completely proprietary bracket for just this motor?? Ive never seen FC brackets, but if i remember correctly the 20b should drop into an FC car so im assuming they are the same (or at least similar). i think the 20b mounts had 2 bolts (maybe im remembering this wrong)...

2) when you buy mounts for the FD they come with the bracket.... im assuming i should be reusing my 20b metal "bracket" (or extension or whatever its called) and add the new rubber/urethane section to that? or will they come as one unit?

pettit says use FD mounts... im assuming they mean just the rubber section of the mount, because the bracket will not fit.... IronMdnX, you used the mazda speed FC ones? did they come with a "bracket", or were they just the rubber section? how is the engine movement with the rubber ones? i was thinking about using urethane since ill be putting more power down and want to keep the engine from twisting (so i dont have to use an engine brace etc).

thanks once again, and sorry for all the questions.... if i had my motor here this would be less confusing hehe. -heath

 

It is just the rubber part. 86-92 All Competition mount
PIC is from Mazdatrix Page



http://www.mazdatrix.com/mounts.htm
Just need to trim the basket to clear part of the subframe.
You use the 20b brackets with the FC or disassembled FD mounts. You can get the fd urethane ones, they were tough to get ahold of when I did my conversion.
I havn't had any issues with the FC ones so there is no point to switch till I break one.

There is very little engine movement that i've noticed. The shifter doesn't torque to one side like my stock FD mounts did on the 13b.

 

IronMdnX - thanks.... EXACTLY what i needed to know. i lost my ENTIRE hard drive 2 days ago, so all of the information that i have been saving for my 20b conversion is now gone.... great timing too because im finally ready to get everything installed. anyway, thanks again. -heath

 

Do you feel any vibrations in the lower rpm's?

 

Maybe a little from 2400-2800, but not bad at all.

 

ok well i just called up pettit and apparantly they recomend different mounts for different frames that they made. the frame that i have is version 2 (i guess they just came out with another one??). anyway i talked to tyler @ pettit, and he said to get some STOCK 1st gen mounts. this strikes me as very odd, as the 1st gen motor was not supposed to put out 500 some odd horsepower. he said that the 1st gen mounts were shorter and thats why he recomends them.... now im not sure what to do. he said that with FD mounts the UIM will hit the hood. this was not the case previously with the 1st frame, so it seems that the mounting points have been raised??? im now very confused.... is anyone using the 2nd frame (completely constructed from scratch? thanks

 

my subframe just got shipped today, i'll let you know what version it is. i'm wondering about mounts also, i was just plannin on ordering some urethane fd ones, but now maybe i should wait to see what will work best.

 

well if its the same frame i have... the second version (they just made a 3rd version i think)... tyler recomeneded the 1st gen mounts because he said the FD ones would make the UIM hit the hood... i dont know. take some pics when you get it, and ill take some pics as well and we can compare.

BTW how much did the frame cost you? did you get the spindles as well? apparantly they went back to welding a bar onto the stock spindles for cost reasons.

 

how do you differentiate from the pettit subframe versions..
are they stamped..
im puzzled how each version would require different mounts...

 

ok, got my subframe today and took some pics. i'm not sure what the different versions look like, but here we go:

and


ok heath, time to compare. i'm a little concerned cause i only got one side of the mounts on the motor. i might have to find the other side.
i was talking to a buddy of mine who just rebuit and ported his fd motor, and he used some type of silicone material for the mounts. its very stiff and should hold up better to the elements than even the urethane. this might be the way i go also when i get some more information on what the material actually is. but he's had no problems, and less vibration than solid mounts.
take a look at the pics and let me know what you think.
thanks!
ah crap, just realized i didn't take pics of the spindles...tomorrow maybe...

 

ok thats what i have basically. im headed home tomorow and ill bring my camera to snap some shots. for the frame i have (and i think its the same one that you do) i was recomended 1st gen mounts which are pretty short. i was thinking of making some the same height as the 1st gen ones but in urethane... although id be a bit worried as the urethane mounts dont tend to give much (and i think the less material, the worse the vibration would get). so im sticking with the competition 1st gen motor mounts for now. if they suck ill change them, but apparantly there are some 1st gen guys w/ 700HP on them, so im not too worried. -heath

(PS ill try to snap some shots tomorow)

 

any pics yet man??

 

yeah... sorry i spaced out... ill throw some up in a second. ok, after looking at your frame more closely.... it seems that you have the 1st run frame (where they cut up a stock FD frame for the mounting points and welded them on to their middle section). i have the 2nd run frame that is constructed from scratch (looks pretty flimsy to me at certain points).... and apparantly they have another one that they are just coming out with. here are some pics of my frame: (for my frame i was told to use 1st gen mounts.... you'd have to call them for the proper mounts for yours

 

yeah, mine seems pretty solid. as long as it works i'm happy.
i also got more info on the mounts that my buddy used. they're actually neoprene. but a hard neoprene, even harder than the stock fd rubber mounts. its still up in the air though. maybe i'll give them a call tomorrow.

 

isnt the mounting point on the 20b cosmo the same as the mounting point on the 13b cosmo? if so you should have got some metal and made ur own mounts

 

ok pics:

 

to me pettits build quality looks pretty bad! id hope for something better built for that price.... oh well i guess as long as it doesnt fall apart?? -heath

 

being built from scratch, i would think that your version would be extremely solid. and for being ~$2k, you would think that they could/would/should do a better job. hopefully it will work fine though.
so are you still going to be using the 1st gen mounts??

 

yeah, im going to try them out and see how it goes (i just ordered a set of the 1st gen competition mounts which are slightly stiffer). hopefully they'll work out ok and will keep the UIM from hitting the hood