Head Work and Custom Cams

[flat_black]

Grrr. =) I want pictures! Ahh, no matter, though. Hopefully once the ECU adjusts, it'll show a nice gain for you. =) If you're losing all that power down low, probably time for a lightweight flywheel so you can get to your revs faster! But that'd be my suggestion.

 

[twilightprotege]

yeah i'm sort of having a tug of war between what i need to do next. at the moment a haltech ecu is winning....need to take even more advantage of the new found breathing ability!!!!!

hell i dunno....too many options, not enough money!

 

[70]

Cool, nice to see that it works well for you...

 

[flat_black]

Yeah, you may be able to gain back the lost low end with an ECU, so try that first, then the flywheel and clutch, probably. =)

 

[PaulMP3]

i think the haltech is your best bet, no one on here that is NA has used a piggyback to my knowledge. Even with a totally stock engine there has to be some more power by messing with the fuel maps.

 

[shinzen]

hey twilight- just cause I am lazy- could post the specifics of what you had done? How much they took out in the port and polish- how agressive with the cams on degree lift and duration- I think I may go that route here shortly and with the gains you are just noticing- may be worth having done....

 

[markmurray77]

Excellent work, hopefully the numbers come up soon. Glad to hear it all went smoothly

 

[akhilleus]

The idle is rough because your cams are sooo aggressive...

 

[RAAZ227]

So the throttle response has improved?? Can you tell that it is really going to get up and go?

 

[Installshield 2]

Excellent work Andy...Did you ever use your custom cam's before the head/manifold work?

and remember the power you already gained can probably easily be doubled once you get your Haltech...

 

[twilightprotege]

flat_black - that's my plans at the moment...just as long as my clutch doesnt wear out too quickly

paulmp3 - that's what i'm hoping. a haltech ecu will help enourmously. esp considering when i hit redline with the engine it wants to keep going. i have to remember to change gears now when before i changed gears when the power started to go down

shinzen - they took a fair bit out of the head. it was visibily noticeable. i dont have specifics but you can tell it was a lot. the cams - quite agressive. something like (i dont have the figures here with me - i'm at work) but it was like 272deg duration @ 0.006", 226deg @ 0.050" and i think 0.33" or 0.36" of lift. i the lift would be slightly more because when i had the head ported i had them put new higher shims in so the valve clearance was 0.009" instead of the stock 0.010"

raaz227 - feels great above 4000rpm!!!! really takes off!!!! i think the work would be more benefitial with a rev limit of 7500-8000rpm...i'll get there one day

install - nah, never got to put the cams in before the head work


all - one thing that's been bothering me is the head bolts. can someone read through the workshop manual and see if they read it the same way as me? i read the bolts should be tightened to so many kg-m which i did, but on the next page it almost looks like they should be tightened a further 180 degrees! i thought that was really strange because there is no way to guarantee the torque each bolt is tightened to with that, so i only tightened them a further 45 degrees from the initial torque specs....can anyone help???

 

[twilightprotege]

boys and girls - flow figures!!!!!!!!!!!!!!! here we go..

air temp 23 deg celcius, 30.04bar pressure, 36.8cc chamber volume, correction factor 1.008

intake :

@ 0.400 lift (i dont have that much lift, but it's between 0.35 and 0.4) - 209.3 CFM

exhaust :

@ 0.400 lift (same issue as above) - 150.7CFM, but they said that's 78.5%....i dunno what that means, but if that was 100% it would be 192.0CFM

happy??? FARK YES!!!!!

they have a little side note (very interesting)....EST HP...GIMME GIMME GIMME i hear you say....

@ 0.350" of lift, 216 SF/HP (dunno what SF stands for)

happy??? see above comment

i know i wont be getting that sorta HP without exhaust and stand alone ECU mods, but very happy....if only they did a before porting flow test

 

[Mike R]

Twilight, the % is the percentage of exhaust flow/intake flow. It's the volumetric efficiency. I personally woulda thought that it would be closer to 90%. But it's not horrible. I would think near 100% volumetric efficiency would be an easy task with a decent designed DOHC head. Heck CHEVY did it with thier 2.3L Quad Four(190HP) years ago.

Let's see some dyno #'s!

 

[twilightprotege]

yeah i thought 78.6% sounded low, but even with 90%, that's still 172.5CFM

both much more than stock head flow stats

 

[Mike R]

Yep very true. Gotta wonder what else could be done to the exhaust side though...

But, it'll take someone with time and money to get a head to a good machinist and have them experiment. Soo, it won't be me!

I'd like to see what "the old one" at Endyn could do for us.....

 

[twilightprotege]

the only way you'll get even more flow outta the exhaust side is by getting bigger valves. in original form they are noticable smaller than the intake side...probably 3mm difference in diameter i'd guess...but there isnt much room to go too big...anyway, you dont want the exhaust to be as efficient as the intake because you'll actually loose power. you want the exhaust to travel out quicker than the air coming in (esp in NA engines due to valve overlap)...you'll be just pumping unburnt fuel out the exhuast if the exhaust side works too well

 

[shinzen]

SWEET twilight- I want it done to mine- betcha pickup more than a couple of hp- how much AU did you have to spend?

 

[Mike R]

Yeah, that's true. All motors the exhaust is smaller, because it's under pressure going out, intake you need the easier flow.

Wonder what's so good about 100% volumetric efficiency then???
(not too smart with engines, I can put them together and understand how they work..but the real nitty gritty stuff I'm ???)

 

[twilightprotege]

the head work cost me $900aud...plus new gaskets (that was $500aud - only genuine mazda available here which kinda SUCKED BIG TIME!!!!)

what's a definition of volumetric efficiency? is it the %age of exhuast flow compaired to intake flow? so in stock form with 183CFM intake and 164CFM exhuast that gives close to 90% efficiency? you'd think porting the exhaust would also increase the efficiency as well???? hell i dunno

 

[shinzen]

So for about $700 usd I can have this done to my es... hmm... I cant wait until the dyno's are posted, I will probably drop the idea of anything else and just get this done to start with