MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: JB21 on November 12, 2020, 08:10

Title: Fitting a functional front splitter
Post by: JB21 on November 12, 2020, 08:10
Looking at purchasing the below, just dubious about how it will perform. It says to bolt up to the bumper and then use support rods.

Obviously attaching it to the bumper alone will do naff all, so presuming the support rods would be what makes it functional being solid mounted?

(https://i.postimg.cc/PJGHPJyQ/s-l1600.jpg)

https://www.ebay.co.uk/itm/Universal-Front-Bumper-Splitter-Lip-169-x-54cm-Gloss-with-RODS-INCLUDED-v8/302826019346

I will also be fitting the below wing in conjunction...

(https://i.postimg.cc/bvb3qvGh/51-I19r-NEp-L-AC-SX679.jpg)

https://www.amazon.co.uk/gp/product/B00DP5LC5O/ref=ox_sc_saved_title_4?smid=A3P5ROKL5A1OLE&psc=1
Title: Re: Fitting a functional front splitter
Post by: Petrus on November 12, 2020, 11:01
Quote from: JB21 on November 12, 2020, 08:10Obviously attaching it to the bumper alone will do naff all, so presuming the support rods would be what makes it functional being solid mounted?

Well no, but what do Í know of your application :-)
Title: Re: Fitting a functional front splitter
Post by: AdamR28 on November 12, 2020, 11:16
£170! No thanks. My advice...

1. Go to B&Q

2. Buy some 12mm ply and a few cans of black spray paint, and a jigsaw if you haven't got one

3. Make something that fits to something solid - chassis rails, subframe, etc.

4. Add tie rods to bumper if necessary (depends how big you plan to go)

5. Be sure to close the gap (if any) between splitter and bottm of bumper - a lot of the gain you'll find will be drag reduction.

Here's one I did a while back:

(https://i1277.photobucket.com/albums/y494/toudou_juku/61510599-B433-4E8A-AB86-2DEE6581AADA_zpsoqulbu6s.jpg)

(https://i1277.photobucket.com/albums/y494/toudou_juku/5812A643-EEF5-44BB-B594-436F20A21CAD_zpsyhrekysz.jpg)

(https://i1277.photobucket.com/albums/y494/toudou_juku/B1913A69-E37B-4BAF-96CE-8C080EE65147_zpsbbv2grp1.jpg)

(https://i1277.photobucket.com/albums/y494/toudou_juku/CC30193E-F4CD-4B06-8979-05E064A22DB2_zps9vhhtmbr.jpg)

(https://i1277.photobucket.com/albums/y494/toudou_juku/B43B4589-600F-4A93-90FF-0970DEDB9E38_zps7z0elsqt.jpg)

Useful link: https://www.verus-engineering.com/blog/cfd-cases-4/post/air-dam-or-splitter-a-closer-look-12
Title: Re: Fitting a functional front splitter
Post by: JB21 on November 12, 2020, 11:53
Cheers Adam, very interesting read. Seems I need a splitter to suit the wing, not the other way around.

How did you find the mx5 after the splitter and wing installation? Is really it worth it?
Title: Re: Fitting a functional front splitter
Post by: AdamR28 on November 12, 2020, 12:12
I never got to drive it on track in the end (customer's car), but it felt quite different on the road (motorway roundabouts) even at 40, 50, 60mph. Matt has done a few vids which may be useful:




I think it is possible to make some significant gains by ducting out of the frunk lid, too. We are especially lucky with the '2 as we have 'carte blanche' in this area!

http://www.flyinmiata.com/support/instructions/misc/louvers.pdf

From what I can work out, cutting holes at the negative pressure areas will 'suck' air out from behind the rad, reducing drag and lift.

Another visual representation:

(https://www.miataturbo.net/attachments/race-prep-75/58067-evo-extractor-hood-vent-miata-e5jyf.jpg?dateline=1350870781)

Line 'away' from body = negative pressure (suction), line 'under' bodywork = positive pressure - so basically, an exit duct as close as possible to the front bumper, but still behind the rad, is ideal.
Title: Re: Fitting a functional front splitter
Post by: 1979scotte on November 12, 2020, 12:24
Quote from: AdamR28 on November 12, 2020, 12:12I never got to drive it on track in the end (customer's car), but it felt quite different on the road (motorway roundabouts) even at 40, 50, 60mph. Matt has done a few vids which may be useful:




I think it is possible to make some significant gains by ducting out of the frunk lid, too. We are especially lucky with the '2 as we have 'carte blanche' in this area!

http://www.flyinmiata.com/support/instructions/misc/louvers.pdf

From what I can work out, cutting holes at the negative pressure areas will 'suck' air out from behind the rad, reducing drag and lift.

Another visual representation:

(https://www.miataturbo.net/attachments/race-prep-75/58067-evo-extractor-hood-vent-miata-e5jyf.jpg?dateline=1350870781)

Line 'away' from body = negative pressure (suction), line 'under' bodywork = positive pressure - so basically, an exit duct as close as possible to the front bumper, but still behind the rad, is ideal.

Just like the elise
Title: Re: Fitting a functional front splitter
Post by: AdamR28 on November 12, 2020, 12:29
Yeah, good shout on that! It's about as similar to the '2 as we'll find I think, apart from perhaps the VX220.

My gut feeling is that the higher the 'line' between front bumper and bonnet the more forward the duct needs to be, hence why the Elise is quite far back - a very low 'nose' - but I may well be wrong!

The Elise has the rad mounted at an angle from memory, so this may also explain the duct being further back.
Title: Re: Fitting a functional front splitter
Post by: 1979scotte on November 12, 2020, 12:42
Quote from: AdamR28 on November 12, 2020, 12:29Yeah, good shout on that! It's about as similar to the '2 as we'll find I think, apart from perhaps the VX220.

My gut feeling is that the higher the 'line' between front bumper and bonnet the more forward the duct needs to be, hence why the Elise is quite far back - a very low 'nose' - but I may well be wrong!

The Elise has the rad mounted at an angle from memory, so this may also explain the duct being further back.

Think you're right about the angle.
Weve got a few members who've had an elise.

I still rate a passenger ride in a vx 220 with supercharged 2.2 as one of my best ever.
Title: Re: Fitting a functional front splitter
Post by: JB21 on November 12, 2020, 13:07
I've spoken to Matt at Oulton, really nice fella. Makes some top video's too.
Title: Re: Fitting a functional front splitter
Post by: Karthoum on November 12, 2020, 15:39
I've got a splitter made for MR2 sizing that I've never got around to putting on and I've changed minds about.

If you don't want to buy a fiberglass one then at least you can take measurements off mine to cut, it's been in the shed forever. Located in Shropshire

IMG_20201112_153216.jpg