M10 Vs M42 (realistically)

[KenH]

3 minutes ago, AustrianVespaGuy said:

What might be most interesting for the OP is: what led you to select the M42 for your turbo build rather than the M10? Looks great and LOTS of ponies in a 2002 though, that's for sure!

 

Very good question.  I had owned 3 02s WAY back in my early 20s.  I started thinking about a car project 3-4 years ago.  I started looking around and driving what was for sale.  I drove some stock cars and some that had the common dual Weber configurations.  I don't think any were really pushing too much power.  I was really underwhelmed on the test drives.  On a lark I happened to go look at a NA M42 car that a FAQ member was selling.  The car ran well enough.  The owner urged me to "step on it".  When it hit around 3300 rpm the engine just came to life.  My eyes lit up and I got hooked.  That particular car's configuration wasn't what I was really looking for.  But that is how I started on my journey to what I have today.  I could just have well driven an 02 with a different engine and gone in totally different direction.  Like most projects, it took longer to complete and I ended up going over my original budget.  I did enjoy the whole journey, I learned a ton too.

 

If there are any other questions, ask away.

[AustrianVespaGuy]

1 hour ago, KenH said:

I did enjoy the whole journey, I learned a ton too.

Hit the most important points then, well done!

[pklym]

My fresh but stock M42 versus a tired M10 is night and day. I wasn't looking for a speedster but now I have something that won't slow traffic, is a joy to drive, and gets better MPG. Sure, I could have rebuilt the M10 to freshen it up, or built it up to match the HP, but it would have cost as much probably and still gotten worse MPG. These cars are light, an extra 20-30 hp is most definitely felt.

[AceAndrew]

To be frank, this question has been beaten to death.  My opinion is as follows, it comes from working with just about every type setup possible.  

 

I echo Toby's, Schnell's, and Ken's sentiments on the M42, it just isn't an engine worth considering.  In my book, the cons far outweigh any positives.  You are giving up .2L of displacement, you raise the center of gravity while simultaneously lowering your ground clearance.  When compared linearly to an M10, the M10 can do everything the M42 can, mod-wise/power-wise.  Boiled down, all the M42 has over the M10 is efficiency of it's dual cam head.  Personally, if MPG was my raison d'etre, I wouldn't have bought a 2002.

 

If you want to add a layer of something "exotic" to the M10 project, consider some variation of a M10 stroker with those fancy new Jenvey Heritage ITB's.

 

Now, if you are talking about about forced induction on the M10 or M42, you are then cutting up the nose, just like you would with an M20 swap (and end up at a similar weight).  At that point, the silky/zippy M20 wins (shoot, in some cases with an M20, you don't need to cut at all!).  However, as noted, that's a debate for another day.

 

Best of luck on your decision.  At the end, do what gives you a warm fuzzy feeling.  You are hotrodding a 2002, as their creators intended.

 

EDIT: cleaning up punctuation, hard to do on phone.

 

 

Edited September 25, 2018 by AceAndrew

[Schnellvintage]

Oh BTW, since it came up 24 mpg mixed city , 32 hwy (non-spirited driving of course). Also for Ken, set it and forget it for any octane gas type and altitude. Not more jets or cold start problems. It really is the best for turn key starting and reliable, fun driving.
Happy motoring,
Matt



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[bento]

A turbo M10 is fun.

This is a stock engine with unknown mileage but good compression and oil pressure. Green is 7psi and red is 10psi. 

 

There was a bit of cutting of the nose- a hole for the air intake.

 

The radiator was also moved a couple inches to the driver’s side to clear the turbo, so the opening had to be widened a bit. I don’t have a great picture of the cut opening, but you can see the opening between the radiator and the turbo.

 

Less cutting than most M20 swaps I’ve seen photos of.

 

At these lower boost levels and with appropriate cooling, it really doesn’t seem to be stressed overly stressed, and the turbo should help compensate for the loss of air density at altitude.

 

Good luck with whatever option you choose.

[irdave]

Do you just want something different?

 

I think a turbo up there would make a big difference- maybe a little bit laggy, but you'll get all the power.

[evil02]

Of course, a Honda F20/22 or k24 swap is something to think about too.

[Schnellvintage]

Hmmmmm has anybody shoehorned a BMW 5 liter V12 from a 750 or 850, in a 2002 yet??? ...that would be something...
[emoji106]


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[TobyB]

It would fit...

 

but the exhaust would have to come out the sides of the fenders.

 

t

[jrhone]

16 hours ago, bento said:

A turbo M10 is fun.

This is a stock engine with unknown mileage but good compression and oil pressure. Green is 7psi and red is 10psi. 

 

There was a bit of cutting of the nose- a hole for the air intake.

 

The radiator was also moved a couple inches to the driver’s side to clear the turbo, so the opening had to be widened a bit. I don’t have a great picture of the cut opening, but you can see the opening between the radiator and the turbo.

 

Less cutting than most M20 swaps I’ve seen photos of.

 

At these lower boost levels and with appropriate cooling, it really doesn’t seem to be stressed overly stressed, and the turbo should help compensate for the loss of air density at altitude.

 

Good luck with whatever option you choose.

 

 

Nice!

 

 

[Dudeland]

A turbo M10 is fun.

This is a stock engine with unknown mileage but good compression and oil pressure. Green is 7psi and red is 10psi. 
 
There was a bit of cutting of the nose- a hole for the air intake.

 
The radiator was also moved a couple inches to the driver’s side to clear the turbo, so the opening had to be widened a bit. I don’t have a great picture of the cut opening, but you can see the opening between the radiator and the turbo.

 
Less cutting than most M20 swaps I’ve seen photos of.
 
At these lower boost levels and with appropriate cooling, it really doesn’t seem to be stressed overly stressed, and the turbo should help compensate for the loss of air density at altitude.
 
Good luck with whatever option you choose.

I just moved my horns to the other side, and put the dryer for my ac back in the stock position. I guess I need to push the turbo back and take the charge pipe strait down, and dump out the hood?


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[bento]

8 hours ago, Dudeland said:

I just moved my horns to the other side, and put the dryer for my ac back in the stock position. I guess I need to push the turbo back and take the charge pipe strait down, and dump out the hood?


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Yeah, charge pipe goes straight down to the intercooler. I don’t have a great photo, but you can imagine a short pipe and couplers connecting the turbo to the intercooler.

 

I don’t want to completely derail OP’s thread. Feel free to PM me with additional questions.

 

*Edit- forgot there was some cutting of the valence for the intercooler. This is all hidden behind an air dam now.

Edited September 26, 2018 by bento

[Luc]

Nice set-up.

I''m building a 2ltr. M10, 118i head with 38 mm outlet valves, 47mm IE inlet valves, 278/262 CatCams, IE 8.5:1 forged pistons (cost no more than stock).

What turbo did you choose?

As to the original question: on altitude a fuel-injected turbo motor is always the better proposition. A few pounds more boost on a M10 will eradicate the better flow of the M42 head and save a lot of work and money.

[bento]

18 hours ago, Luc said:

Nice set-up.

I''m building a 2ltr. M10, 118i head with 38 mm outlet valves, 47mm IE inlet valves, 278/262 CatCams, IE 8.5:1 forged pistons (cost no more than stock).

What turbo did you choose?

As to the original question: on altitude a fuel-injected turbo motor is always the better proposition. A few pounds more boost on a M10 will eradicate the better flow of the M42 head and save a lot of work and money.

I went with the Turbonetics Super 60. No complaints so far. My power goals are fairly modest after I rebuild the engine- 250whp or so and this turbo should support that no problem.

 

I’ll probably go with a very similar engine build. I’ll be very interested to see how it does on the dyno when you get it running.