M20B35 small perf mods advices

[pegase747]

Hi from France,

I would like to mod my Touring M20B25 to gain little power. i dont plan to rebuild the engine now, so no 2.7 conversion yet.

The plan is to do the following :

- Miller MAF Gen3 conversion with matched Miller chip.
- Keep the original airbox but with a better filter ( I heard that direct induction will not add much, unless expensive ! ).
- BBTB and reworked original manifold ( one fo the forum member sell them right ).
- M50B25 injectors for better rate and spray.
- stainless manifold and exhaust system.


After that next mod could be a camshaft ( 272, 276 or even 288/272 ) with matching valve springs.

Now the questions :

- What gain do you think I can achieve in terms of HP ?
- Will I need anything else than the Miller chip with this mod, for Engine management ( what I mean is : with the bigger injectors and BBTB & reworked manifold, will than need to be tuned also or just plug & play ? )
- where would you buy the best exhaust system and header for a good power gain, but not overly noisy ?
- As for the camshaft, what would be the most useable for daily use, but giving a good increase in perf ? Compromising...

I'd like to know all that from you experience guys !

Hope you can give me answers...

Regards from France / Pierre

[SpecM]

sounds good, minus the bbtb

[pegase747]

sounds good, minus the bbtb

Whats wrong with BBTB ? someone enlightens me pls !!

Pierre

[SpecM]

Whats wrong with BBTB ? someone enlightens me pls !!

Pierre

doesn't help power output, and will wreck your throttle response

[nando]

doesn't help power output, and will wreck your throttle response

that depends on the mods to the motor. It will only hurt throttle response if it's not a restriction.

to measure that you would need to know the pressure drop across the TB. Basically you could do this with a map sensor, and measure at WOT on the inside of the intake manifold VS atmospheric pressure. If theres a big differential (5-10% at least) then a BBTB would help. but if the pressures are equal, then it will not do anything except make throttle transistions feel flat.

[pegase747]

thanks Nando, very informative.
By the way what is the general consensus about the MAF conversion ?
I believe the enginee will response much faster, but any power increase ??

rgds / Pierre

[nando]

maybe a small one, but to be honest it's not the best way to spend your money. you could get a half decent standalone for a little bit more.

[digger]

maybe a small one, but to be honest it's not the best way to spend your money. you could get a half decent standalone for a little bit more.

but factor in proper tuning and its a different story cost wise.......

also a BBTB will increase response at low throttle openings but it will reach effective WOT much sooner and the last bit of movement will do nothing and feel flat so if you want throttle response mess with the gearing on the throttle linkage and keep it stock

[ADEN]

guys look look at the title m20b35 ???????

[Holland]

guys look look at the title m20b35 ???????

Title got me too.

[pegase747]

sorry mistyping, that was M20B25 of course !!

Pierre