Sumo Rivet/Bolt on Bonnet Scoop

[Grumbleweed]

Hey.

My plan has always been to cut out the original MK3 bonnet scoop and add a larger rivet/bolt on one. Searching on here, there are a couple of threads on the matter but I cant seem to find a definitive answer if it has been done and how? Speaking with the other suppliers, I think only the larger DAX and AK Supercharger scoops are big enough to cover the hole that would be left, the Old Ford Auto ones look like they have a ridge running down the middle which I don't really want.

Any advice/images would be greatly appreciated.

Thanks.

[philbrad73]

I plan on doing similar, but for a narrower scoop. So I will have fibreglass the hole to suit the new scoop. When I bought my body l did ask for a bonnet without a scoop but was told they don't do them anymore.

[Grumbleweed]

I plan on doing similar, but for a narrower scoop. So I will have fibreglass the hole to suit the new scoop. When I bought my body l did ask for a bonnet without a scoop but was told they don't do them anymore.

you need to find out what bonnet this is then! https://www.ebay.co.uk/itm/AC-COBRA-...MAAOSwof5gPogS

[aaronjb]

you need to find out what bonnet this is then! https://www.ebay.co.uk/itm/AC-COBRA-...MAAOSwof5gPogS

Given the size of the scoop that used to be there .. I'd guess at older Dax maybe?

[KevinW]

Be useful to state what the width of the Sumo scoop is front and rear.
IIRC older Sumo bonnets are single skin apart from the perimeter, whereas newer ones have a complete inner skin on the underside.
If you have an older bonnet, then its not that hard to cut out the old scoop and bend a piece of ali to match the curvature and then fibreglass from underneath.
Doesn't need to be perfect because you are going to remove most of it anyway when you fit the new scoop.
A double skin makes the job a bit trickier.

[Grumbleweed]

Thanks Kevin.

Mine will be the newer double skin. According to Pilgrim the scoop is 635mm long, 380mm at its widest point at the front and 39mm high at the front.

DAX = 900mm long x 400mm wide x 80mm high

AK Supercharger = 730mm long x 490mm wide x 50mm high

Be useful to state what the width of the Sumo scoop is front and rear.
IIRC older Sumo bonnets are single skin apart from the perimeter, whereas newer ones have a complete inner skin on the underside.
If you have an older bonnet, then its not that hard to cut out the old scoop and bend a piece of ali to match the curvature and then fibreglass from underneath.
Doesn't need to be perfect because you are going to remove most of it anyway when you fit the new scoop.
A double skin makes the job a bit trickier.

[Grumbleweed]

FYI this bonnet comes from a BRA 289

you need to find out what bonnet this is then! https://www.ebay.co.uk/itm/AC-COBRA-...MAAOSwof5gPogS

[Grumbleweed]

Any thoughts on benefits of either bolting or riveting the scoop on? I would assume peel rivets for a gel coat?

[aaronjb]

I was planning on using small dome-headed allen bolts & nyloc nuts, personally; mostly because I very much dislike riveting into fibreglass. That said, peel rivets are something I just learned about

[KevinW]

Don't rivet it on, it will make a mess of the grp. Original cars were an ali skin which would have been fine.
Take some small stainless allan head bolts. Some people nut and bolt them. I drilled holes and tapped the grp so they dont show though on the other side.
Alternatively you can use short self-tappers.