Making an M40 a bit nippier

[alexbaker1989]

If you've read my intro post you'll know I'm expecting to make an offer & pick a 318i M40 up very soon.

I know people have asked many times about performance upgrades on M40's but with unrealistic goals of massive power increases. This is not that!

I already own an E36 IS with an M44 in it, so know how that feels to drive performance wise. It keeps up with modern traffic and is nippy enough for me.

Any suggestions on a few relatively simple modifications to squeeze another +/- 20 or so bhp from an M40? I'm not interested in an engine swap as to maintain as much originality as possible.

Am assuming there are a few options:

-A good, full service
-Decent NGK's with spark gap checked to be in spec
-Magnecor HT leads (partly for aesthetics)
-Decent exhaust
-Decent intake (seen the dBilas ones for sale and like em')
-Chip? (subjective as to where I source one of these)

Imagine that will get me roughly 15-20bhp...?

I know ITB's are an option but that's too much money. Maybe one day.

As long as it makes the car sound a bit throatier and it feels perkier (and a bit closer to an M42 / M44), then I'm happy.

[Cloggy Saint]

I'm no expert but I don't see anything on your list that will gain 15-20 bhp. If your current plugs/air filter and leads are knackered (leads tend not to degenerate) then you may gain a bit of grunt and a chip might give you a bit extra but nothing too noticeable. My advice would be to give it a thorough service and enjoy it for what it is. If you throw £££ at it hoping for big power gains (20bhp is almost an extra 20% increase!) you'll be disappointed.

[alexbaker1989]

I'm no expert but I don't see anything on your list that will gain 15-20 bhp. If your current plugs/air filter and leads are knackered (leads tend not to degenerate) then you may gain a bit of grunt and a chip might give you a bit extra but nothing too noticeable. My advice would be to give it a thorough service and enjoy it for what it is. If you throw £££ at it hoping for big power gains (20bhp is almost an extra 20% increase!) you'll be disappointed.

Fair, however wouldn't you think a combination of these options would altogether gain a circa 10-15% increase in power? If so, I'd be happy with that along with a throatier engine note and a bit more grunt. With an engine as lethargic as an M40, I'm sure a 10% increase in horses would be noticeable.... correct me if I'm wrong.

P.S. i'm not looking for "bang for bucks" as such here. There's no quantifiable increase that would or wouldn't justify the cost. Many of these options are not going to break the bank, apart from ITB's.

[stones]

-A good, full service
-Decent NGK's with spark gap checked to be in spec
-Magnecor HT leads (partly for aesthetics)
-Decent exhaust
-Decent intake (seen the dBilas ones for sale and like em')
-Chip? (subjective as to where I source one of these)

Imagine that will get me roughly 15-20bhp...?

I know ITB's are an option but that's too much money. Maybe one day.

As long as it makes the car sound a bit throatier and it feels perkier (and a bit closer to an M42 / M44), then I'm happy.

A proper service is the best place to start, make sure you get the injectors serviced if they haven't been done, also carefully check the intake boot for any cracks. Best to take it off and look as they often start to go on the underside and it's hard to see. Manifold gaskets can also be worth replacing and the breather pipe.

Spark plugs and HT leads not going to do much unless they show signs of needing doing anyway.

Exhaust, if you can find a suitable 4-1 exhaust manifold I would say thats a better buy than a new 'sporty' exhaust. (I personal feel they just add noise and possibly don't help bottom end power) Custom could be an option but bigger £ just don't think that a bigger bore means more power.

Intake not sure if you are looking at this:
https://dbilas-shop.com/en/intake-tract ... b16/m40b18

or
https://dbilas-shop.com/en/intake-tract ... 1-8-8v-m40

????
And as for a chip i have looked several times but never found one convincing most seem to make crazy claims.
The other thing you haven't mentioned is the cam. Lots to choose from depending on how harsh you can handle.
Not sure you would get +20bhp as said above.
HTH

[alexbaker1989]

Thanks for the replies. Went to see the car today, made an offer and left a deposit- so am picking it up next Sat.

It's been loved its entire life and is only on 58k miles, so I expected there to be no mechanical issues. The engine ran very well, and felt great to drive. It ticked over nicely and sat on idle very smoothly. It's recently had an INSP II so think it's running as good as it should. Seems like its worth exploring the ITB route in future as the dBilas package includes a camshaft, so it's an all-in-one solution.

The only slight niggle I had with the car is a groan on the steering rack once when parking. I've read that this is probably air in the system. It's had recent fluids changed by a specialist so perhaps it wasn't bled properly. I didn't find any leaks and the steering was very light - almost lacking feeling a bit - but I guess that's how all E30's are....

[Caravanking]

There's a cam available by piper but not sure about any of the specs of it.

https://www.larkspeed.com/category/view ... -Kits-BMW-