M20 B3x Naturally Aspirated Stroker build past, present and future

[digger]

The pads I use are very aggressive. Carbotech XP20 front, Hawk DTC 70 rear. They are able to bring the car from over 100 to 30 just after the 200 foot marker on the track, but when slowing on the street, it sounds like a garbage truck. They will put your face in the dash at the end of my street, first thing in the morning.

hawk HP+ are also similar to this otherwise i would try them.

[digger]

I Played around with similar things before in solid works but you need port pressure as a function of time and pressure depends on the inlet so it is iterative. The solve time is a lot longer. I designed the airbox to be large so that it is effectively like open trumpet. If I had used a smaller volume airbox then there would be more Merit in a transient analysis. The BMW manifold plenum has small volume and if you compare the torque curve the small plenum of the BMW appears to hurt torque at 2500rpm (even with long skinny runners) but helps at 3500rpm. Where as when I added the airbox there was no real tuning happening over the open trumpets just an overall small increase. plenum /airbox volume appears to work in a narrow rpm band where it resonates at the same frequency as the engine but you get a negative boost elsewhere

[ForcedFirebird]

The pads I use are very aggressive. Carbotech XP20 front, Hawk DTC 70 rear. They are able to bring the car from over 100 to 30 just after the 200 foot marker on the track, but when slowing on the street, it sounds like a garbage truck. They will put your face in the dash at the end of my street, first thing in the morning.

[pantelones]

please sell it and use something better in that case.

I actually LOL'd

Ha yeah..... I just don't understand why people think that they can argue with physics.


Anyways, have you done a dynamic flow test like this?




I was brushing up in Solidworks for some projects in the near future, and will be designing manifolds for both intake and exhaust using the flow simulator. I also really like the way Newman made his turbo manifold in Sw and used the 2d drawings for templates. This video was pretty neat in showing how to maintain the overall length while changing the tubes themselves.






Good progress digger! :up:

[digger]

For street pads, maybe. I bear with the noise and just leave my race pads on all the time (use it in events about once a month). Can't keep the wheels clean for long with them, either though.

my wheels get dirty but the jurids and textar have the best initial bite when cold which makes the pedal feel a little more linear.

tried some race type pads ages ago (local brand) but they needed to get to temp before they started to bite, they did bite very very well though.

will need to do a big refresh, lines, calipers rebuild at rear and maybe BBK or just a rebuild of front calipers etc then a flush and bleed etc

linkage for RHD that goes across from the drivers side to the passenger side to the booster doesnt help and sometimes adjustment helps.

i guess the lower vacuum from the engine doesnt exaclty help either

[ForcedFirebird]

im running stock pads and rotors, the stock pads feel alot better than others ive tried.

For street pads, maybe. I bear with the noise and just leave my race pads on all the time (use it in events about once a month). Can't keep the wheels clean for long with them, either though.

[digger]

What kind of pads are you running ? A decent pad makes a huge difference if you are not already running them.


Also, we are going to need some videos up in here.

im running stock pads and rotors, the stock pads feel alot better than others ive tried.

[evandael]

damn. that's a nice powerband and excellent results for 80's engine architecture.

nearly 100 more bhp than a stock m20!

[LJ851]

Definitely needs more brakes, the pedal travel versus braking torque should be more linear and less effort to bite. tyres will limit peak braking torque but at the moment its hard to access it all the braking performance

What kind of pads are you running ? A decent pad makes a huge difference if you are not already running them.


Also, we are going to need some videos up in here.

[digger]

spring tension has been increased and it drives like a dream.

Definitely needs more brakes, the pedal travel versus braking torque should be more linear and less effort to bite. tyres will limit peak braking torque but at the moment its hard to access it all the braking performance

a 5mm spacer with 16" Alpinas allows UUC 11.75" kit and massive 11" perhaps even the 11.75".

[digger]

Nice !

This is still with your old exhaust, correct?

How high are you revving it to on those graphs ?

yeah not redone exhaust yet....currently planning that doubt that will be done before end of june. should be some pretty decent gains in midrange i think.

3400rpm is 100km/h IIRC so 6700rpm or so. limiter is 7100rpm and pulls easy to there but wasnt hitting in in these runs

[LJ851]

Nice !

This is still with your old exhaust, correct?

How high are you revving it to on those graphs ?

[digger]

final results are in now that everything is tuned.

It just goes to show that ITB and new induction system can make more power everywhere and there are no downsides once you use the right diameter runners, right runner length and feed it cold air.

Made 160rwkw (215rwhp) on one run but this is the best overall powerband.

best part of 30whp gain peak to peak which is a difficult task on the m20

first graph is 42mm ITB, 12" runner length and custom GRP/CFRP airbox and K&N filter Vs a BMW OEM casting with some massaging done to it



the setup with the airbox trumped the open trumpets, which was good, though some no doubt due to the tune.

graph is as above but with open trumpets also added into the mix




had a few issues, the throttle got jammed WOT on the dyno (better there than on the street). Already had a spare at home because it started to look a bit frayed. the internal sheath deteriorated due to long term heat exposure from the exhaust is my guess and added too much friction. had to baby it home but all sorted now. i now realize it had been on its way out for a long time as the pedal is so touchy and responsive now with a brand new cable. i will adding a bit more spring tension to make it a little easier to drive otherwise it will be a handful in the wet.

[bmwandhonda]

that 12 kw doesn't include the probably 10 kw from sucking in 60C air instead of 30C so its worse than that.....when the hood is open on the dyno you get cooler air.

im enjoying the added performance more than im missing the sound TBH

This is true.

[digger]

I am currently getting an ITB'd m20 tuned atm (still at the shop) and will be running individual dry filter socks. Surprising that there is a 12kw difference between the open trumpet, no filter setup :/

That is a big power difference when it comes to an NA engine.

As much as power/efficiency is more important, the sound is something i just don't want to lose by boxing them up.

Anyway, will keep checking your thread for more updates.

that 12 kw doesn't include the probably 10 kw from sucking in 60C air instead of 30C so its worse than that.....when the hood is open on the dyno you get cooler air.

im enjoying the added performance more than im missing the sound TBH