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V8 Conversion advice
Posted: Wed Oct 31, 2012 10:06 am
by Staty
I have been toying with either a turbo or engine transplant for a while now, just bored of the 2.5 straight 6, its not fast enough. It was so fast when i got my 1st e30 about 12 years ago. The turbo idea has now passed, want something a bit meaty, so seems the way forward for me is a V8 lump. I have found one, but before i just go out and buy it, i'd like to get an idea from you guys who have already done similar conversions as to what else i have to change/upgrade and what sort of costs I'll be looking at. The engine i'm looking at is from a E39 540, m62 4.4 engine with 6 speed box. As always, any advice is greatly received.
Cheers guys.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 10:54 am
by mcbonio
I personally do not believe the e30 was designed to bear such a load up front, nor does it has the suspension setup for it. Nor will it put the power down effectively.
Your best bet would be an m50/m52 engine. Or even an m30b35, I have one in my e30 and I tell you its plenty fast.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 11:00 am
by Staty
Good suggestion, are both these engines are from e36 3 series?
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 11:22 am
by Motorhole
Alternatively, if you have the cash and you want a V8, go for a Chevy LS and Tremec T56 'box. Engines from 5.7 litres up to 7 litres. But they are compact and lightweight, being all aluminium and not having head gear associated with double overhead cams. I do believe the 5.7 is a good few kgs lighter than an M20.
Even the basic 5.7 litre will produce 330bhp on a bad day, 450bhp easily achievable. 600bhp+ from a 7-litre.
I would do this if I had the time, space and most importantly, cash.

Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 11:27 am
by mcbonio
Yeah they are from e36, and some early e46 I believe. I think they are lighter than the M20 engine and there are lots of tuning options available too.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 11:41 am
by Staty
That looks like a pretty crazy idea! I'd imagine them engines cost a fair old wack? I'd quite like to keep it bmw though. If they are lighter then the M20, may be a good shout for my e30! Something is getting dropped in there, just need to find the best option and then buy it!
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 11:47 am
by Motorhole
Staty wrote:That looks like a pretty crazy idea! I'd imagine them engines cost a fair old wack? I'd quite like to keep it bmw though. If they are lighter then the M20, may be a good shout for my e30! Something is getting dropped in there, just need to find the best option and then buy it!
Looking at about £4-£5k for an engine and 'box imported from the states. Plus custom engine mounts, gearbox cross-member & mounts and propshaft. Probably a custom rad too. And you'd be wanting to beef up your brakes, suspension and driveshafts somewhat too!
Apparently it all fits without mods to the bulkhead etc though.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 11:53 am
by Staty
Think that is a little rich for my blood! Would be pretty awesome though, quite like to buy a donor car with a decent engine and gear box and just wack it in!
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 2:22 pm
by bss325i
mcbonio wrote:I personally do not believe the e30 was designed to bear such a load up front, nor does it has the suspension setup for it. Nor will it put the power down effectively.
Your best bet would be an m50/m52 engine. Or even an m30b35, I have one in my e30 and I tell you its plenty fast.
I'm pretty sure that an M30 with its iron block weighs more than an M60/62 which has an alloy block.
The M30 is also longer so will have more weight past the front axle line than the M60/62.
300-350bhp is about the most an E30 with a semi trailing arm rear suspension and 225 rear tyres will take before it becomes a tyre shredder.
The Hartge H35-24V was about 315bhp.
An M60/62 is only 286bhp.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 2:41 pm
by capnmchl
But HP is a pointless and it's torque which really counts, and apparantly a M30B35 makes 305Nm and an M60B40 makes 400NM.
Although interestingly, the M60B30 only makes 290Nm.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 3:01 pm
by bss325i
capnmchl wrote:But HP is a pointless and it's torque which really counts, and apparantly a M30B35 makes 305Nm and an M60B40 makes 400NM.
Although interestingly, the M60B30 only makes 290Nm.
This is true. 250-300lbft is about the limit for the previously mentioned E30 suspension design and tyre size.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 4:27 pm
by penton08
I have just finished fitting a m62b44 into an e30, It handles fine, possibly better than my s50'd turd!! It actually has quite good traction too! The torque is not as brutal as the figures would suggest, it comes in nice and low and is more of a steady surge than even my m52 which comes in as a big lump later in the rpm's.
I must point out that this is in a sorted car, with new bushes and a decent suspension set up. In an old creaky, unloved turd I have no doubt it would behave like a drunk donkey

Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 4:55 pm
by Staty
Good stuff, so you would recommend going for it? What else did you have to change on your e30? I have a pretty good suspension set up, but if a new set up is needed, its needed! Cheers guys, you lost my with torque talk.
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 5:13 pm
by AndyTB
New to the forum, long time lurker though!
I'd be keen to know what problems you had with the swap too - I'm currently plotting a rebuilt M62B44 into a 318is for the new year down here (sorry, "y'ere"!) in somerset..
Especially how you got around the Manifold issues the M62 creates (y)
Re: V8 Conversion advice
Posted: Wed Oct 31, 2012 5:55 pm
by capnmchl
I think everyones contemplated this swap at some point. There's quite a few good guides out there. I think heavily modified X5 manifolds are what I've read.
http://e30v8.plainsimple.dk/
This one seems quite good. See the bottom of that page for a rough idea of what you need.
Re: V8 Conversion advice
Posted: Thu Nov 01, 2012 2:02 am
by reepers13
i have a m60b40 in mine with bc coilovers.. car is for drifting however im not sure what diff is in there.. its welded and the acceperation is brutal!!! very short ratios..
but its a hard car to skid thats for sure and ill need some more practice...
for the sheer noise and power id recomend!!
ps im running 235/245/ 17" on a 10j rim et20 at the rear... no problem spinning 4th/5th in the wet with the 6spd box
i didnt do the conversion but from what i know the 4.0 has a handful of wires for the loom as oposed to the 4.4 and for an extra 10ftlb i dont see the point in the 4.4
Re: V8 Conversion advice
Posted: Thu Nov 01, 2012 9:58 am
by Staty
capnmchl wrote:I think everyones contemplated this swap at some point. There's quite a few good guides out there. I think heavily modified X5 manifolds are what I've read.
http://e30v8.plainsimple.dk/
This one seems quite good. See the bottom of that page for a rough idea of what you need.
Looks like a nice conversion! Kinda wish i had the space time and skills to do it myself! In an ideal world i'd like to give my e30 cab to someone, supply them the engine and gear box and some money and they can let me know when its done. Any offers, inbox me & yes i'am being serious, cheers
Re: V8 Conversion advice
Posted: Thu Nov 01, 2012 10:25 am
by Funnybear
A v8 in a cab might not go so well. Even a well sorted cab surely must suffer from torsion twist. I've got a cabby, and whilst I'd love to think it could handle a v8, I'm not sure the chassis and body is really up to the job. I think I'm right in saying that you can't fit rear suspension turret bars like you can in the other shapes. Can anyone correct me there?
A v8 is my ultimate goal as well, but I don't think a cabby is the car to do it with.
And having read that 'how to' post, thats one hell of a lump to have over the front axle line. That thing surely can't handle at all well. And whats the power to wieght ratio between that and a well sorted six pot? It can't be that much of a difference.
Re: V8 Conversion advice
Posted: Thu Nov 01, 2012 6:05 pm
by capnmchl
Again though, the M60B40 delivers far superior torque to the M30B35. 100NM isn't something to be sniffed at.
And if you consider the all aluminium V8 blocks against the big cast iron M30 blocks, the weight saved is shown even more with the increased torque figure.
An S52 will probably be about the same weight as a V8 block, and it does deliver more torque than the 3l V8. But then a straight 6 will overhang the front axle more than a V8.
If you look at it, it's pretty equal runnings. I don't think either's a winner. I will say in my experience V8's have much lower peak torque and a lot more grunt throughout the rev range. Straight 6's do have good torque but they tend to peak pretty far along the rev range.
Re: V8 Conversion advice
Posted: Fri Nov 02, 2012 8:45 am
by Phill172
The weight of a V8 really is no concern. With a bit of planning you can get the engine sat nice and low and a fair way back, unlike alot of the yeeha conversions iv seen the are bulging out of the engine bay.
Staty wrote:capnmchl wrote:I think everyones contemplated this swap at some point. There's quite a few good guides out there. I think heavily modified X5 manifolds are what I've read.
http://e30v8.plainsimple.dk/
This one seems quite good. See the bottom of that page for a rough idea of what you need.
Looks like a nice conversion! Kinda wish i had the space time and skills to do it myself! In an ideal world i'd like to give my e30 cab to someone, supply them the engine and gear box and some money and they can let me know when its done. Any offers, inbox me & yes i'am being serious, cheers
Slinging a V8 into a E30 is pretty simple. You can buy the relevant engine mounts and wiring a M60B40 is simple.
The difficult parts are the servo, which can be a simple fabrication, depending on what route you take. And also the manifolds.
I have said alot of times yet still get ignored, X5 manifolds do not fit RHD E30 V8s, E34 540, E39 540, E38 740 stock manifolds do not fit.
I dont see any as a better starting point. The stock manifolds are so restrictive as standard but when they are cut/welded/cut/welded they will be awful no matter what route is taken.
There is a company who make bespoke manifolds for a E30, (also have some that need fabricating if anyone knows a good/reliable fabricator)
The company who made the manifolds, if i remember they retailed around £1000.
For a bolt on part and not to mention performance gains its a no brainer. Believe me it is far easier then having to sit under a car and undo/doup the manifolds 10 times before it even fits
Re: V8 Conversion advice
Posted: Fri Nov 02, 2012 4:28 pm
by AndyTB
Ah that's useful to know - Any idea what the company that made the bespoke manifolds were called??
Re: V8 Conversion advice
Posted: Fri Nov 02, 2012 6:30 pm
by Jimbob
Re: V8 Conversion advice
Posted: Fri Nov 02, 2012 6:53 pm
by Phill172
I believe the company was J2P or JP exhausts.
Yes the Lh bank looks like an x5 manifold however it's still modified as the standard down pipe will go straight into the starter motor. The point I am trying to make is that so many people saythe x5 manifolds fit with no modification on a rhd e30
Re: V8 Conversion advice
Posted: Fri Nov 02, 2012 6:59 pm
by Staty
I have been thinking about this and think the best option is for me to keep my e30 as it is, concentrate on getting cams and other m20 performance parts and buy a e39 m5, can use the m5 in the winter, take the cabby out in the summer. That way I'll have both the e30 that i love because of its classic looks and style and a touch of modern comfort and power from the M5! Fair play to you guys that have already done conversions, if i could do it myself I'd probably be a bit more inclined to move forward, also I don't think my cabby could handle that much power, she's getting old!
