NA track car. What to bin? What to keep?

[Roverload]

Hi all, I've got the front bumper off (finally) and I'm doing a bit of pre planning for when I start super charging. I'm still on the bodywork at the moment but I'd like to increase the amount of useable space between the engine and the bumper. I'm going to bin off the front crossmemeber in favour of a welded in bar but I'd like to bin the big plastic re-enforcement peice and the polystyrene part that's stuck to it. Has anybody done this and did your front bumper start to sag or change shape afterwards? My plan is to mount the new radiator at a 45 degree angle with a built in scoop in through the grille and out through the bonnet, the inter cooler would need to go around the area where these re-enfocenent parts are. Any tips on other things to bin off would be appreciated too!

Ian

[Mr MXT]

I took 100kg out of my Mk1 and weighed everything.

PM me and I’ll send you the spreadsheet.

[Mr MXT]

I got your message, did you get my reply? The email address looked a bit “made up”

[Roverload]

Hi! Yes I did receive it. Thanks for that. I was quite surprised how light your cage was. Do you have a build thread for the car at all? I'm curious to see how you made certain parts lighter.

[Mr MXT]

Not a cage, it was a TR Lane roll bar (GPX I think?)

No thread sorry but happy to send some pics but be quick before it gets scrapped

[Roverload]

Ahhhh yes I know the one, Great value for money! I'd been looking at the GPX on bofi racing's website. Wont be getting mine until kids go back to school. I've ran out of project car money until then 😐

[GC8]

Are you scrapping that lovely green RS? I still have the original seats from that car.

[Mr MXT]

Who me?

[GC8]

Yes.

[Mr MXT]

That was mk2 - the next owner wrote it off

[GC8]

[RSTurboPaul]

Roverload said:

Hi all, I've got the front bumper off (finally) and I'm doing a bit of pre planning for when I start super charging. I'm still on the bodywork at the moment but I'd like to increase the amount of useable space between the engine and the bumper. I'm going to bin off the front crossmemeber in favour of a welded in bar but I'd like to bin the big plastic re-enforcement peice and the polystyrene part that's stuck to it. Has anybody done this and did your front bumper start to sag or change shape afterwards? My plan is to mount the new radiator at a 45 degree angle with a built in scoop in through the grille and out through the bonnet, the inter cooler would need to go around the area where these re-enfocenent parts are. Any tips on other things to bin off would be appreciated too!

Ian

I appreciate none of us plan to crash but will the lack of any impact absorption material not mean any impacts are very hard on the driver?

It could be worth looking up some aero / wind tunnel info for the rad/bonnet aspects - I am sure the top of the bonnet is an area of positive pressure, so if it is, it may restrict airflow out of any hole(s).

I'm not sure you'll have any cooling issues with an alloy rad in the standard position and oil coolers for the charger and the engine itself - one of the chaps on Mighty5s has a 300bhp turbo and no unusual cooling layouts IIRC.

[Roverload]

RSTurboPaul said:

Roverload said:

Hi all, I've got the front bumper off (finally) and I'm doing a bit of pre planning for when I start super charging. I'm still on the bodywork at the moment but I'd like to increase the amount of useable space between the engine and the bumper. I'm going to bin off the front crossmemeber in favour of a welded in bar but I'd like to bin the big plastic re-enforcement peice and the polystyrene part that's stuck to it. Has anybody done this and did your front bumper start to sag or change shape afterwards? My plan is to mount the new radiator at a 45 degree angle with a built in scoop in through the grille and out through the bonnet, the inter cooler would need to go around the area where these re-enfocenent parts are. Any tips on other things to bin off would be appreciated too!

Ian

I appreciate none of us plan to crash but will the lack of any impact absorption material not mean any impacts are very hard on the driver?

It could be worth looking up some aero / wind tunnel info for the rad/bonnet aspects - I am sure the top of the bonnet is an area of positive pressure, so if it is, it may restrict airflow out of any hole(s).

I'm not sure you'll have any cooling issues with an alloy rad in the standard position and oil coolers for the charger and the engine itself - one of the chaps on Mighty5s has a 300bhp turbo and no unusual cooling layouts IIRC.

I'm happy to be proven wrong but it is my understanding that heat is a deffinite issue. The data I've seen on the aerodynamics section of miataturbo.net pinpoints the exact location where the vent needs to be. It also eliminates alot of the turbulence around the front grille. I'm also not into fitting the intercooler in front of the radiator so it needs somewhere of it's own to live and that plastic thing is a prime location.

[GC8]

There are cooling issues but they arent centred around the radiator.

A normal radiator will be perfectly adequate.

Id focus my attention on a coolant reroute.

[RSTurboPaul]

Roverload said:

I'm happy to be proven wrong but it is my understanding that heat is a deffinite issue. The data I've seen on the aerodynamics section of miataturbo.net pinpoints the exact location where the vent needs to be. It also eliminates alot of the turbulence around the front grille. I'm also not into fitting the intercooler in front of the radiator so it needs somewhere of it's own to live and that plastic thing is a prime location.

Thanks for the aero graphic!

I guess you could perform a set route / stress test with the OEM system and then repeat it with the proposed alternative system - would be interesting to see the results.

[Roverload]

RSTurboPaul said:

Roverload said:

I'm happy to be proven wrong but it is my understanding that heat is a deffinite issue. The data I've seen on the aerodynamics section of miataturbo.net pinpoints the exact location where the vent needs to be. It also eliminates alot of the turbulence around the front grille. I'm also not into fitting the intercooler in front of the radiator so it needs somewhere of it's own to live and that plastic thing is a prime location.

Thanks for the aero graphic!

I guess you could perform a set route / stress test with the OEM system and then repeat it with the proposed alternative system - would be interesting to see the results.

I'd be keen on that, I was planning a base run track day this year with the engine and associated systems in standard form. Probably at Castle Coombe. I'm no aero engineer but theres certainly a reason a good amount of race cars run this ducting. I know it's just a track day toy before people say I'm going too far but that's the whole point of this car. I've always wanted to go nuts on a car and see what I can build. I've got flat floors and diffusers drawn up, its gonna be great fun!

[RSTurboPaul]

Roverload said:

RSTurboPaul said:

Roverload said:

I'm happy to be proven wrong but it is my understanding that heat is a deffinite issue. The data I've seen on the aerodynamics section of miataturbo.net pinpoints the exact location where the vent needs to be. It also eliminates alot of the turbulence around the front grille. I'm also not into fitting the intercooler in front of the radiator so it needs somewhere of it's own to live and that plastic thing is a prime location.

Thanks for the aero graphic!

I guess you could perform a set route / stress test with the OEM system and then repeat it with the proposed alternative system - would be interesting to see the results.

I'd be keen on that, I was planning a base run track day this year with the engine and associated systems in standard form. Probably at Castle Coombe. I'm no aero engineer but theres certainly a reason a good amount of race cars run this ducting. I know it's just a track day toy before people say I'm going too far but that's the whole point of this car. I've always wanted to go nuts on a car and see what I can build. I've got flat floors and diffusers drawn up, its gonna be great fun!

Flat floors? Diffusers?

In that case, proceed as you were - the madness has already set in lol

[griffdude]

GC8 said:

Id focus my attention on a coolant reroute.

+1

[GC8]

I wouldnt make a car that sucks itself down without looking long and hard at the suspension mounts.

[Roverload]

GC8 said:

I wouldnt make a car that sucks itself down without looking long and hard at the suspension mounts.

Advice and suggestions always welcome. I'm not arrogant enough to think I know it all and have all the answers. It's not just a case of building whatever i like the look of, it's as much a research project as it is a trackday toy project. Its early days, I'm still on bodywork and getting the car sound and useable. It's a long road ahead.