Chazzmanbm
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| posted on 24/5/26 at 02:47 PM |
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JFDI (Just F****** Do It) Time
Hey Folks,
I am completely new to the world of kit cars but have always wanted to build my own car and I think a Locost or 7-style build would be the perfect
platform to teach myself the skils necessary to build a car. I am not an automotive engineer but I am not completely useless either as I have worked
on motorcycles and cars for decades, just not "real engineering" work. I took a welding course 4 years ago with the intention of building a
project but for many reasons, haven't gotten started.
I've reached the "shit or get off the pot" stage so I bought the Chris Gibbs book, downloaded the VoDou and McSorley plans from the
Internet and am trying to consume as many build videos as I can. I've seen some amazing builds by some seriously talented people but in my case,
my ambition and talent are on opposite ends of the scale.
In any case, I will start with the Gibbs chassis and maybe the VoDou plans if I use an MKII MX-5 donor ....or the McSorley 442. In my head, I want to
build my dream car for fast road and UK Tracks but my dream is to take it on a track day at Spa. Power-wise, I want something between 350 and 450
horsepower with a stout diff and transmission. There are LOADS of engine choices and I will figure out what I platform to use when a decent donor
comes up. I know, I don't NEED that level of power but if I am building my car, I might as well build it the way I want.
So, with all that said, I want a strong, safe and secure chassis for my project and I am not sure the standard Gibbs chassis would do the trick.
.....or am I wrong? Engine speed and power has moved on so much since the Locost chassis was designed and I am wondering what people are doing to
increase the strength and safety. Is it simply a case of using thicker box-section steel and adding more triangulation? What are your thoughts?
Thanks guys.
Chazz.
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gremlin1234
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| posted on 24/5/26 at 03:47 PM |
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yes go for mx5
I doubt you want 500 HP/Ton unless you have already done track racing.
I suggest, build it as max 200HP/ ton, then upgrade after its on the road.
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Chazzmanbm
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| posted on 24/5/26 at 04:07 PM |
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I have done a bit of track work, which is another reason for the build. I can always turn up the power but I can't always re-engineer the
chassis to suit, not easily anyway, so I'd rather "over-engineer" it as I am building it.
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adithorp
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| posted on 24/5/26 at 04:17 PM |
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Yes, go for it!
However 350-450bhp will cause you all sorts of packaging issues. A 7 iengine bay is limited. Getting enough coling for a start with rad, oil cooler
and intercooler. What power units were you thinking of? When you've managed that you need to consider, can you put that power down on the road.
You're more likely to find yourself going backwards into the scenery.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Ugg10
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| posted on 24/5/26 at 04:47 PM |
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Good luck on your build.
Just a couple of comments if I may.
It’s worth reading the IVA manual if you intend on road registering the car, the plans you identified I think are pre-IVA and so some modification may
be required e.g. seat belt mount points, light positions etc.
For an engine you could start off with the 1.8 MX5 and then add a turbo kit which are readily available, this would get you to around 250-280hp
without too many internal changes. An alternative is the Honda K24 (check engine height) which again can be turbo’s to around 500hp without opening up
the engine and if you felt ambitious and have a good budget you could bolt (kits available) a BMW DCT box to it using a MaxxEcu to control it, this
would give you 7 gears with those super fast changes.
That said, for fast road in a seven style car I think 175-200hp is the sweet spot I.e. you can drive it to 9/10 without it getting into big trouble,
250-300hp would be a real handful on the road and 350-400hp would need a new pair of underwear every time you go out. Remember that you need brakes,
diff and suspension to be able to transmit that power to the road and stop the car which will add to the build. I suspect you will need a budget of
around £15-20k to do it right.
All the best and do keep us updated with progress.
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Slimy38
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| posted on 24/5/26 at 05:09 PM |
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If you want to put a bit more into the chassis as you build it check out the 'aussie mods'. Their registration process demands a higher
rigidity so there are instructions out there that add a great deal of strength for not a great deal extra metal.
Personally I focused on getting the car road legal first, then I can look at more power if I want to. I've seen reports of a fair few builders
trying something decent under the bonnet but then struggling to get it through IVA.
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Chazzmanbm
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| posted on 24/5/26 at 05:29 PM |
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Thanks for the tips everyone. If I can find an affordable Mk2 -> 2.5 MX-5, I will likely use that as a donor. I am a big fan of turbos so ideally
that's what I will be building so it could be the MX5 1.8 engine or maybe a K20. If I use MX5 running gear and engine, as Ugg10 says, 250-280
would be the maximum. I've been in a 7 with 200ish bhp which had great handling and stopping power but I felt it could use more to give me the
rush I am after.
The main thing for me is to get started with the build. I've been thinking about this for waaaaaay too long and I really just need to get
started. Whatever the build ends up being, donor, engine and power-wise, we shall see but I will get stuck in on my build incorporating the
"Aussie Mods".
Cheers all.
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Ugg10
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| posted on 24/5/26 at 05:42 PM |
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If this is primarily a track car have you thought about bike engines.
You could go down the “added lightness” route. The classic combination is a Hyabusa engine that can be turbo’d or supercharged to around 300-350hp but
in a sub 500kg car if you are careful with equipment choices. The only issues would be that you would need the 3.3cwp for the mx5 diff as the stock
3.9-4.3:1 diff are too short for a bike engine, or go down the BMW 166 diff, the z8 had a torsen diff with around 3.1:1 diff iirc.
A more modern alternative would be the Kawasaki H2 supercharged engine, these are north of 200hp stock with a filter, exhaust and ecu remap but you
can add an intercooler and re-gear the supercharger drive to increase boost to around 300hp. This is a 999cc engine and you get a free 6 speed
sequential box.
For turbo, I believe the K24 is a better engine and re much cheaper (around £1k for. jDM 200hp version) but re about 20-25mm taller so need to check
bonnet clearance.
Too many options.
[Edited on 24/5/26 by Ugg10]
[Edited on 24/5/26 by Ugg10]
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Chazzmanbm
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| posted on 24/5/26 at 07:15 PM |
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I have thought about bike engines and have chatted to a few people who have put them in their cars. The Hyabusa engine is attractive with the benefit
of sequential transmission. The possibility of adding flat-shift would be awesome too but I don't know how smooth it would be on the road, also
I'm not sure how the clutch and transmission will cope long-term having to propel a vehicle that is 2 to 3 times heavier than what it was
designed to. I know loads of people run Hyabusa engines in their cars but I am leaning towards a car engine for the torque that comes from the added
capacity. If someone gave me a decent Hyabusa engine to use for my build, I won't say no though. 
A K24 sounds like a lot of fun too. I assumed they would be difficult to find in the UK though. Hmmmmm.....
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Ugg10
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| posted on 24/5/26 at 07:31 PM |
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The K24 are fairly easy to find. If you search eBay or Facebook marketplace there are a couple of sellers in the West Midlands that import them by the
container load as far as I can tell. I would expect you could find adaptors for a Aisin 6 speed box from an RX8/MX5/200SX/IS200 that would be just
about Ok for 300hp in a light car. These are basically the same box but with different input shafts and engine bolt patterns, in the SX200 it can
handle 250hp/250ftlb in a 1.5ton car and in the RX8 it revs to 9k plus it is helical so quite quiet. But this might need some tunnel mods to make it
fit as it is a little bit bigger than the Type 9 that most seven chassis are designed for. Getting a type 9 to take 300+ hp is not going to be cheap
or not even possible so the RX8 box at £200-300 basically makes it a consumable. The top end would be a Quaife QBE60 sequential but at £5k for used
item this is not cheap.
Example of a K24 in a MK Indy, they seek engine mounts for the k24.
https://usa7s.net/ips/topic/15902-mk-sportscars-rx5-vtec-k24/
There is a MK Indy chassis for sale on Facebook marketplace place if you want to save a bit of hassle.
[Edited on 24/5/26 by Ugg10]
[Edited on 24/5/26 by Ugg10]
[Edited on 24/5/26 by Ugg10]
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Chazzmanbm
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| posted on 24/5/26 at 08:14 PM |
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I like this idea, although it has opened up a whole can of worms and modifying possibilities. I am already deep down in the Google and YouTube rabbit
holes on this topic.
Back to reality, I need a chassis first. I am an absolute sucker for punishment and don't want to deny myself the opportunity (pain) of building
my own car from scratch, with my own hands. ...and I want to do it on a budget. There's a book out there somewhere that says it is possible.
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Steve Hignett
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| posted on 25/5/26 at 11:43 AM |
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You should be realistic (with yourself) re the time period to build though also.
I have no budget, so I have to build my own.
I also want mine to be.. well, mine. So, it's a fully round tube lightweight Locost.
However, with family stuff, a full time job, a few other commitments (and in my case, having to wait for payday to be able to afford the next bits)
all takes it's toll on the length of build.
Whatever you think it will take, double it. Or even triple it.
I'm not totally clueless and unfamiliar with builds, but I'm 15 months into my 12 month build with about another year to go...
All the best with it all!
Steve
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Chazzmanbm
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| posted on 25/5/26 at 11:59 AM |
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You're not wrong Steve. My fear is exactly the same as most people when embarking on a big project. Obvious things like time and money,
motivation especially when things aren't going smoothly, then there's scope-creep with the "Oh, I'll just .......".
I am an idealist but also a realist and intend to stick to a proven formula i.e. use the documents and plans that have been followed successfully my
many others before me and use parts that will fit, while still putting a personalised spin on it. Even with all that, success isn't guaranteed
so planning and sticking to the plan is equally important.
I am great at planning, it's the execution I'm not that great at. If only I can get my wife to 'encourage' me to work on building
the car like she does with household jobs.
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