Head Work and Custom Cams

[twilightprotege]

cam gears are definately the next step. if i were to put an exhaust system on right now, i'd loose even more power down low and only gain once again at redline. if i can move the power band down by 1000rpm, i'll be peaking a lot earlier and should get a fair bit more power.

and i need to lean out the engine too - that's why a standalone will be after the cam gears

 

[mp5jeff]

in your 1st expectance post you wanted 15-20whp from this and you saw about 10whp, so its not too far off from what you were expecting, once you get the cam gears and stand alone id like to see your numbers then..

 

[twilightprotege]

yeah i'm not far away from what i wanted... just needs tuning

 

[thewrench]

An old thread on pclub that might be of a little interest. I don't what this ever led to. It sure piqued my interest at the time.

http://www.protegeclub.com/forum/showthread.php?s=&threadid=24465

JT

 

[twilightprotege]

all i can say is "i need cam gears and a day on a dyno!!!!!!"

 

[Installshield 2]

yeah man, I forgot about that thread but remember reading it...He was gaining over 10whp with the cam gears (the throttle body was just bored a few mm and had a new butterfly from what I remember...probably didn't make a noticable difference with that mild engine build up, same goes for the drop in filter)...and remember that was with north american cams...You could see much more gains with your J-spec one alone...I don't even want to start on what it "could" be with your current setup...Do it and let us know...!

 

[green MP3]

hey dude..
Do not be disappointed,even though i did say in a past post that you were gonna be with your ecu.
what you have done to your car is great but you will not see any huge gains until the ecu,air/fuel ratio, fuel pressure and ignition system is modified. Once you do that it will be a whole different game. You will gain alot and i mean alot of power. i am going as you are with a turbo so it will be even better for this type of set up. Just wanned to tell you to keep the faith. I felt just like you when i did it but now that is running much better i am happy and with more stregh to keep tuning. i will make my car a 320 hp at the wheels, that is a promise and as i get better tunings with dyno proven evidence, i will spill the beans and let you in.
We did it backwards as someone mentioned but i kinda knew that,only that now we can get any mod and make our cars fast and eventually furious.
it won't be that expensive to tuned, you'll see.

regards
Green

 

[flat_black]

Yeah, man. =) You're the single hope for all of us N/A freaks! Hehee. Even if you are planning on a turbo. It's great to see someone taking the low road for once, to see what can be done with this engine. =)

 

[twilightprotege]

thanks green.

and all - i hope once i can get the cam gears sorted you'll all start thinking beyond the square - go for bigger cams than j spec and porting the head etc....

 

[giskard]

I'm late to this thread but here are some comments. This stuff I gleaned from "four stroke performance tuning" by A G Bell and from playing with "Dyno 2000" engine simulator.

1) cams with lots of overlap need tube headers to work properly. Overlap allows the exhaust gas to scavenge and suck in intake charge, but only if the exhaust gases in the exhaust manifold runners have momentum (aka velocity). I see you have a de-catted stock exh manifold, that can't be good for scavenging, because they have very short runners. Not only do the gases have to have momentum, the runners have to be the right diameter and length so as to provide the right "pulse tuning frequency" and provide a boost to your torque at around 5000 rpm (for a street car) The header tuning works hand in hand with your cam overlap period. (which is tunable with cam gears)

A large overlap tends to make for a strong midrange. A strong topend comes from a late closing intake valve. What are your valve specs? (IN, EX, opening and closing angles at 0.050" lift)

2) In theory, ideal cam specs are generated by software by examining your head's flow numbers.

3) The P5 motor is limited in power by the valve diameters. They are the same as the 1.8 Miata motor, for example, and they can only do about the same peak power. The valve sizes are limited by the bore - the BP and FS motors have the same bore. The extra displacement of the P5 motor (from the stroke) means that power peak happens at a lower RPM, and the midrange of the P5 motor can be fatter.

Headwork can make the valves "look bigger" and so you can get more power.

I see you got headwork - do you have the flow numbers? Good headwork yields a 4-8% increase in flow at all lifts. Gains at low to medium lift is more important than at high lift (>6mm) because the valves spend more time partially open than fully open. With stock cams, good headwork seems to help torque at all RPMs.

Do you know what he did with the headwork? Did he just do a general cleanup and 3 angle valve job (always works to some extent), or did he just hog out the ports (doesn't work), or did he do more drastic things like raise the port floor and knife-edge the dividers (real pros do this but requires a flow bench and experience to know what works)

Since your gains are all at > 5500 rpm, your cam specs are all wrong - a good street cam upgrade should yield more torque from about 3000 RPM and up. Indeed it may just be a matter of cam phasing. Aftermarket cams should always be degreed and setup with cam gears.

A big exhaust will not tend to reduce low RPM torque. You should measure your exhaust backpressure. Remove the O2 sensor, find a bolt that screws in partway, drill a hole through said bolt, force fit about 8 inches of copper tube, fit some vacuum hose over the end of the copper tube, string it to the cockpit, and connect it to a boost gauge. If you have over 3 psi of backpressure at high RPM WOT, you will probably see noticeable gains from a big exhaust. You will also probably find that the factory cat is the biggest restriction (if you compare the backpressure before and after the main cat).

Cheers.

 

[twilightprotege]

ok....a reply!

1) yep. stock exhaust sucks...but i dont want to play with it because i'm getting a turbo down the track...well i might put an AWR header on and hi-flow cat and cat back, but not sure. probably only a 15% likelyhood of this happening.

my cam specs (both intake and exhaust) :
gross lift 0.3512"
cam durations @
.010 - 272.5deg
.020 - 250.2deg
.050 - 225.9deg
.100 - 199.4deg
.200 - 147.4deg
.300 - 82.7deg

anything more you need or would like to know?

2) very true. but to some extent, the head can be matched to the cam specs. this is what the head shop did to mine

3) yes i got the head ported. here are the specs :
intake CFM @ (lift)
.050 34.6
.100 70.9
.150 105.0
.200 136.5
.250 162.9
.300 182.3
.350 198.9
max 209.3

exhaust CFM @ (lift)
.050 28.6
.100 60.2
.150 82.4
.200 114.5
.250 131.2
.300 140.4
.350 146.8
max 150.7

anything more you need or would like to know there? the work they did was slightly more than a general clean up, knife edge the dividers and 3 angle valve job. port match intake manifold ofcourse

cams were designed in theory to give a lot of valve opening for when i go turbo. cam overlap does need to be altered now and for turbo ofcourse

what's your experience from or is that text book knowledge?

 

[akhilleus]

Why did u do all this work if u r going turbo..? Its seems to be self defeating. You should have gotten the turbo first and then worked the engine....especially if u only had the head ported and polished/cams...if u were gonna do engine work with a turbo @ high psi you should have gotten forged components instead.

 

[slenser]

I personally think he is doing things just fine. He will have much better results with the turbo, when he gets it, because of all the work he has done to the engine. I don't know what kind of boost he plans on running, but from what I have seen, these engines do fine without upgrading the internals for quite some time.

If you want him to build his engine a certain way, I'm sure he will be more than happy to accept your contributions to improve it the way you feel fit. If not, let him do what he wants, how he wants and in the timeframe he wants to do it in.

DAMN, everybody's a critic!

Twilight, cudos on the work you have done.

Sam

 

[akhilleus]

Hey dont get all jumpy...I thought that initially twilight had focused on an NA buildup....thats why i wondered why he is adding the turbo. Either way though until he gets that engine tuned...turbo or not...it wont be what it can be

 

[giskard]

ok....a reply!

1) .. i'm getting a turbo down the track...well i might put an AWR header on and hi-flow cat and cat back, but not sure....

Well if you go turbo the big exhaust will benefit you even more. So you can go big exhaust now, as long as it's not too loud for you.


my cam specs (both intake and exhaust) :...
Do you know what the stock cams are? It's useful to know where you are against a known starting point.

I noticed that your intake and exhaust durations are the same. If the stock cams have more exhaust duration than intake, it may be because the head likes it that way (i.e. the exhaust valves/ports are a bit restrictive), and so it's generally a good idea to keep the same relationship when upgrading cams. Also, increased lift is only useful if your headwork has improved flow at high lifts and if your new cams have significantly more duration than the stock cams near its max lift. Increased lift, more aggressive ramps, and an increased revlimit, all require upgraded valve springs.

For turbo apps, stock-like cams generally give the best street performance. If anything, perhaps slightly longer exhaust duration and reduced overlap would help.

Did you tell the cam guy you're planning to go turbo?


2) very true. but to some extent, the head can be matched to the cam specs. this is what the head shop did to mine
Eh? The head characteristics are pretty fixed and the cams are full custom.. therefore the cams should be tailored to the head, don't you think?


3) yes i got the head ported. here are the specs : ...
Again do you have the before figures? Flow benches vary in absolute numbers, so the comparison should be % changes vs. stock.

the work they did was slightly more than a general clean up, knife edge the dividers and 3 angle valve job.
Did they back-cut the valves? That nearly gives as much improvement as the 3 -angle work on the valve seats.

cams were designed in theory to give a lot of valve opening for when i go turbo.
Do you mean duration or lift?


cam overlap does need to be altered now and for turbo ofcourse

Ditto.

what's your experience from or is that text book knowledge?
textbook, helping more than one friend with their NA and FI buildups, and DIY headwork on my turbo miata and my old college car, and watching others' buildups on miata.net.

One guy LOST torque at all RPMs from a cam swap. He too had no gears, but he'll be tuning new gears in a few days.

Another guy had impressive NA gains - but he did EVERYTHING.

 

[twilightprotege]

akhilleus - i did all this work because i wanted more power now, but then everything is set for turbo....and i wont need to touch the engine anymore (well you get the idea). i definately didnt want to get forged internals now because the stock compression ratio on my engine is 9.7:1 (aussie version). i want 8.8:1 compression when i go turbo, so doing that now is beyond useless

slenser - thanks man. encouragement is always accepted . fyi - i plan on running around 14-18psi.

giskard (replys are in order) - on my car the stock intake was jspec and the usual exhaust. i have the specs around, but cant put my hand on them at the moment. they are on this site hundreds of times.
the reason why my intake and exhaust cam specs are the same is two fold. first one is simplicity and cost. second is the main reason - because the exhaust side of the head flows less than the intake, it was most benefitial for a turbo setup to get the exhaust out as quickly as possible (quicker turbo spool). in stock form the exhaust cam is smaller than the intake cam. and like you said, for turbo apps, slightly longer exhaust duration works great for street apps.
heads can be modified to suit your needs....yes cams can be taylored a lot easier, but those are the cam specs i really wanted.
original head flow - dont have figures for my head, the head shop didnt do a test (tossers)
did not get the valves cut back
cams give much more duration than stock

all - i know i have a lot of work to do. cam gears are absolutely next (plus a day of dyno tuning)

 

[akhilleus]

Ok...first i hope i dont offend by what i am gonna say...but what r u smokin.! U want to run that much psi w/o getting forged rods...good luck. Second how are u gonna lower your compression by almost 1 comp point when u have cams that are aggressive with a port and polish and a 9.7:1 comp pistons. U would have to run pistons that are pretty low...and or shorten your stroke. The only reason I am saying this is that with just a small amount of work you could have a badass NA car...which i thought was what u were doin...dont sell us NA people out, we are counting on your success.

 

[Installshield 2]

Ok...first i hope i dont offend by what i am gonna say...but what r u smokin.! U want to run that much psi w/o getting forged rods...good luck. Second how are u gonna lower your compression by almost 1 comp point when u have cams that are aggressive with a port and polish and a 9.7:1 comp pistons. U would have to run pistons that are pretty low...and or shorten your stroke. The only reason I am saying this is that with just a small amount of work you could have a badass NA car...which i thought was what u were doin...dont sell us NA people out, we are counting on your success.

14psi with excellent tuning is a possiblity on the stock internals, and remember 14-18psi on a 8.8:1 compression ratio is a little easier on the internals than 9.1:1 on the same boost...Without a standalone it is a pipedream...

He can pretty much tune the cams with cam gears to lessen the overlap if needed, so they are pretty flexible...

Also, his turbo work won't come for a while, and he said he may get a full exhuast replacement in the future...I just want to see his gains with the Haltech and cam gears...

 

[akhilleus]

yeah but how is he gonna lower his compression to 8.8:1 when he is @ 9.7:1 ....mazdaspeed pistons?

 

[Installshield 2]

uh...custom I am assuming...Mazdaspeed pistons would raise it?