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Post by V6 on Jun 30, 2019 14:36:20 GMT
The J32A (JDM spec) or J32A2 (North American version) variants make 260bhp in the Type-S donor car. Thats with the very restricted small manifold and downpipe. Removing that alone apparently frees up over 30bhp. Reasearching these incredibly easy gains on the Accord forums is one of the reasons I went for this route. There are lesser versions as well, from lesser spec cars. This is the reason for different bhp figures quotes for similar "J swaps". Wiki has lots of info. Weight and BHP for each version does vary! The power to weight is the best on the J32A or J32A2. If you get the wrong one you add mass and have less power. So worth researching / double checking before you purchase. Some claim they have one example, but have been wrong. The Type-S has different throttle intakes and codes stamped on them.
In my conversion the engine and kit adds 4kg to the OEM MX5 mk1. However removing the massive Honda plenum and dual throttle gubbins, then replacing with a lighter Holley should bring that down to OEM mass in total.
In addition the Holley adds circa 6% even on already highly tuned engines. Adding more flow via ported headers and large bore throttle adds more again. Without modding the engine at all, over 300bhp is appraently easy to do. P2R tuners in USA claim 318bhp (without the Holley and larger throttle, but with the ported runners, large bore manifold etc).
Total weights is best done after. Different sub frames will change things too. So I'm happy to trust the 4kg added in total on mine.
My engine also had a fair bit of excess mass removed: huge cast engine mounts, some shaft mounting castings, power steering pump, pulley, plus the tensioner for ancilleries. All suprisingly heavy and now gone. So the weight figures is likely wrong also.
If you go for an LFX don't forget to add... Weight of thicker center shafts, upgraded rear shafts and hubs, different gearbox, different diff, factor in whatever the subframes are.
Also the Greek guy suggests the LFX is 305bhp in his. So not sure why this is a lower figure? Either way, the LFX is a large capacity engine and makes more torque than mine. Hence needing all the shafts etc upgrading. Just like Lexus V8 swaps... a tad too much grunt for the MX5 parts to handle. This is why I don't want to do the 3.6 litre upgrade to mine... too much torque, hassle, cost.
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jon
Chats A Lot
Posts: 270
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Post by jon on Jun 30, 2019 16:46:16 GMT
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Post by Vindi (Russell) on Jun 30, 2019 17:34:58 GMT
Good stuff, thanks guys. I got confused with all the Honda J30 / 32 information, and was also a bit nervous of all the issues with the sumps getting ripped off. I think this was mostly the earlier design, although I'm not sure ... warrants a revisit anyway. I thought I was headed for about 250-260bhp which was another part of why I sold up my J swap kit ... mine was a J30 of some sort though ...
The One Lap Heroes guy I'd trust on his figures ... there are a lot of differences between how different countries and dyno types measure power, which makes it hard to work out!
The LFX swaps were measured on decent corner weights, with a complete working car ... before and after the completed swap, so they are accurate at 30kg weight lost.
Russell
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Post by V6 on Jun 30, 2019 17:39:47 GMT
End of the day the LXF is a larger capacity and will have more torque. Like a Lexus V8. All else is splitting hairs on peak bhp +/- claims. This is both superior, but also a pain in the rear canoe in equal measure  |
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Post by wannabe on Jun 30, 2019 21:16:31 GMT
Good stuff, thanks guys. I got confused with all the Honda J30 / 32 information, and was also a bit nervous of all the issues with the sumps getting ripped off. That reminds me - have you asked them to work up a sump protection plate yet, V6? lol |
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Post by V6 on Jun 30, 2019 21:36:12 GMT
Yes ages ago. It was in my thread. I wanted an RC10 style angled kick up plate.
At a later date I'm open to a dry sump conversion.
Step one... Get the damn thing finished! 😁
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Post by V6 on Jul 1, 2019 21:44:10 GMT
I was watching this vid and thought of this thread. Maybe less grunt isn't a bad idea haha...
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Post by Vindi (Russell) on Jul 2, 2019 9:16:02 GMT
Ha ha, perfect example of why you don't actually need much power on the road ... I'd certainly need to exercise some restraint if I had over 300bhp in my 5!!
As I'm making some lists and adding up the costs, it's dawning on me just how long this would realistically take. Yes, I'd be building potentially one of the best / fastest MX5s in the UK ... but would I ever get there?
I'm wondering about breaking it down into a 3 or 4 part project. It makes sense because I could stop at any point (sounding a bit too much like an addict there!)
Stage 1 would be get it on the road in a standard format ... just to shake it down again & get brakes, handling & interior sorted properly. It's not been on the road since 2015, and it's never been on the road with the cage so there's a lot of bits that might need changing around to get it right for me.
Stage 2 could be some form of power increase, whether to a basic turbo, charger or a cheaper V6 swap. Main reason for this would be to test everything again under more stress, and changing the back end around to a stronger setup. It might seem a bit crazy to do something that I'd need to undo, but it's only really time that I'd lose. The parts tend to hold their value and the prop is the only bit that couldn't be reused ... they are £160, so not a huge deal
Stage 3 would then be up to LFX .. if I felt the need by then. That's the other reason for stage 2 ... I may well happy with that, so I could just freeze there and develop it a bit more if needed.
So thinking along those lines, what's the cheapest ways to power? Turbo ... under £1000 if done cheaply. Cheapest V6 swap? KL probably?
Russell
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Post by V6 on Jul 2, 2019 9:37:15 GMT
"Best" will always be subjective. Some purist nerds may say we have ruined our cars by changing anything from OEM spec.
Some want speed. Some want good sounds. Or add in anything else which tickles your pickle... Low mass, smoothness, scary ass turbo kicking in, rare JDM unicorn spec etc. All depends what you are into.
I'd also wager the turbo cars will always be the fastest. Some are pushing insane bhp and torque. Hence their disposable gearboxes! If you want the fastest I'd suggest an Evo engine and full transmission swop into a mk1. That would be another level of insanity. Never seen that.
I'd decide what you want and ignore everyone else. If it's right for you, then you will never consider selling it.
My wishlist may be different to many. But on mine was: reliability, good sounds, smoothness, crisp throttle response, same mass as OEM, oh yeah and the power increase would be fun.
If you ignore many of the above you could easily make a faster one.
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Post by scottydugg on Jul 2, 2019 10:10:52 GMT
Stage 1 seems a good way to go, also the quickest way to get it on the road and start enjoying it (but you do have the Lotus so maybe you don't need that).
I'd be contemplating going straight to Step 3 as you've got the use of another car whilst you carry out the work. Looking at your last post in the NA vs FI thread, I'd be surprised if you didn't go straight to a low weight NA V6/V8, since you've already done all other FI options.
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Post by Vindi (Russell) on Jul 2, 2019 17:13:25 GMT
I'd also wager the turbo cars will always be the fastest. Some are pushing insane bhp and torque. Hence their disposable gearboxes! If you want the fastest I'd suggest an Evo engine and full transmission swop into a mk1. That would be another level of insanity. Never seen that. I'd decide what you want and ignore everyone else. If it's right for you, then you will never consider selling it. My wishlist may be different to many. But on mine was: reliability, good sounds, smoothness, crisp throttle response, same mass as OEM, oh yeah and the power increase would be fun. If you ignore many of the above you could easily make a faster one. Looking at the track records and the way they are being broken, the LFX is faster than the turbo cars, even those with more power. Partly the amount of power and torque from so low down in the rev range, and partly the weight / balance of the car. I had a 4wd MX5 early on, 2012 or something. Interesting car but XR 4x4 based, so an evo version would be nicer to say the least! I think my wishlist isn't much different to yours, although a big part of mine is that I want to build it myself, and ideally it's something a bit different Russell |
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Post by apextwin on Jul 2, 2019 19:47:18 GMT
Any pics / info on the 4x4 car! Sounds crazy!
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Post by V6 on Jul 2, 2019 20:50:35 GMT
Sounds like you really have done it all. Impressive history and skills. I'd love to learn to get more involved on the proper mechanical side, rather than just the interior, cosmetics, support odds and ends. Never enough time it seems. Always other non car projects on the go. I'm surprised the turbo cars are not still top of the lap times. Evo based car... 600bhp, 4WD, mega torque, low ish mass. Would be untouchable I'd have thought. More like Veyron pace in a mk1 lol. "Simple" version... Buy an Evo... Cut the mk1 body floor and tunnel out. Drop it onto Evo chassis. Connect the two parts with a ton of cage and steel plates. Drive it out of the garage by tea time. Post your build thread in the afternoon... |
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Post by V6 on Jul 2, 2019 22:53:16 GMT
Or...
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Post by Vindi (Russell) on Jul 2, 2019 23:35:28 GMT
Sounds like you really have done it all. Impressive history and skills. As with a lot of the cool cars I've had, I bought the 4 x 4 already done. I have some mechanical skills but no real fabrication skills ... I've built a couple of kit cars but that's just bolting stuff together, takes patience but no real skills that can't be learnt along the way. I'm just full of ideas, and not quite clever enough to realise I shouldn't really be attempting things that are way above my skillset ... then too stubborn to let them go when I should call it quits. It's why I manage to do a lot ... but it's also why I get myself in waaaaay too deep on some projects! Luckily, I live in the black country so there seems to be an endless supply of good engineers and fabrications who are only too glad to part this fool from his money and make things happen Russell |
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le sigh