Thread: S/C bolt size question

if you really wanted something unique you could get studs and then just use nuts to tighten it down.

otherwise i want to say they are M8?

AH! i thought you meant the bolts that went into the LIM through the blower/intercooler. disregard my comment.

i have no idea what size those are. i would just take them to any hardware store and line them up against other bolts.

GenIII M90's:
For the snout to the case:

You will need:
9 - M8x1.25x55 bolts.

If your blower is machined, and has the outlet modified and the two lower bolt boss's are gone then you will need 7 of the above metric bolts, and 2 M8x1.25x45 bolts so they don't poke into the outlet.

If you want the same metric bolts to bolt the GenIII M90 to the lower intake manifold (LIM) then you will need the following for a GenIII M90 with NO inter cooler under it:

*NOTE:*
You will no longer have the bolt with the stud on top of it that holds the EGR heat shield in place if you go this route.

1 - M8x1.25x85
1 - M8x1.25x65
8 - M8x1.25x45

If you want to also hold the bracket that holds the MAP and some EVAP stuff to the back of the M90 with the same metric bolts then you will need 2 additional M8x1.25x45 bolts. Not required, but just to keep all the bolts the same.

GenV M90's:

For the snout to the case:
If you want to remove the T40 Torx bolts, (if yours was equipped with these as some were not) and install something close that looks the same, then you would want a button head bolt for looks.

You will need:
8 - M8x1.25x45 bolts.

With a button head bolt, they do'nt have a whole lot of material on them for high torque so be careful or buy socket head bolts instead in the size above.

If you want the same metric bolts to bolt the GenV M90 to the lower intake manifold (LIM) then you will need the following for a GenV M90 with NO inter cooler under it:

1 - M8x1.25x140
1 - M8x1.25x120
1 - M8x.125x80
7 - M8x1.25x40

If you would also like to replace the PVC cover bolts, as well as the vacuum 3 way that sits on top of the blower, and the BBV bolts, with stainless socket head bolts, then you will need:

6 - M8x1.25x20 metric bolts.

For those with a GenIII M90 and still retain the stock fuel rails, you can also get the same bolt above for the fuel rails that bolt to the top of the blower, you will only need one additional bolt. (I also use a thin small stainless washer for my installs myself) GenV guys...you don't have a boss so don't sweat it.

Where to get these bolts:

I have been ordering my bolts from Bolt Depot - Nuts and Bolts, Screws and Fasteners online as their prices are very fair and shipping is not bad. Sure you can also find these same bolts at most local hard wear stores, but as with anything like these, you will wind up paying double in price that way.

There are many other places on line that sell metric stainless steel bolts, but I have found that Bolt Depot - Nuts and Bolts, Screws and Fasteners online has the most complete selection anywhere I have looked.

Hope this list of bolts needed and sizes helps everyone who is interested in doing this for their cars. Received many emails asking, and figured this would be a easy way for everyone to read whats needed. -Print off and save

~F~

I used to replace all these bolts with stainless steel bolts when ever I would polish up or rebuild a M90. I bought them by the box in bulk to save everyone money who wanted them.

Now, I take the stock OEM M90 bolts, and have them HARD chromed. (hard chrome plated). Looks just as good IMO. Started doing these this way after I tried it out on my own GenV after I polished and rebuilt that one (the first GenV to ever be polished) and it worked out fine, and looked pretty damn pimp, so been offering this service on all my polishings and rebuilds ever since.

~F~