CulRidr's MP3 N/A build (~150whp goal)

[LordWorm]

O2 clamp? Might consider that...would make things a lot simpler. Selling the MP3 ECU would provide some cash. I'd just have to play with the VTCS solenoid so that a regular ECU would not go nuts...

not sure if they are clamping, or just shorting it out when they don't want it - clamp will hold it at a predetermined AFR - it'll still try and fuel "intellegently" at that reading...turning it of would leave the computer with no option but open loop....of course i've never personally done this - just theorising out loud

 

[MakeMeGoFast]

Can you even go by what the you guys are doing across pond since your all OBDI?

 

[CulRidr]

I want things to be as legal as possible (deleting my 1st cat is technically legal since I've had OBDII codes say it isn't working properly, for which I SHOULD be able to get documentation from the dealership to make it official). Clamping should be OK, the other stuff, I don't know. I just want nice AFRs at full throttle. I'm around 14.5 at cruise, but more like 12-13 at WOT no matter what I tell my piggyback...I guess that's the closed loop doing it's thing eh?

I'm not too worried about that right now though as running a little rich at WOT isn't a big deal. What I'm more worried about is timing with the higher compression and the twiggys. Do you have insight/links/advice/whatever to pass on? I haven't read much about it yet, but the last thing I want is to start the car and it going nuts because timing is all off. I'll of course be running premium, but will stock timing be able to handle the HC?

 

[LordWorm]

Can you even go by what the you guys are doing across pond since your all OBDI?

dunno...maybe
you're not fiddling with the diagnostics system....you're tricking the computer into going open loop...only difference might be the shiney CEL light when you do it.

as i said, theory...i could be way off, wouldn't be the first time!

 

[LordWorm]

I'm not too worried about that right now though as running a little rich at WOT isn't a big deal. What I'm more worried about is timing with the higher compression and the twiggys. Do you have insight/links/advice/whatever to pass on? I haven't read much about it yet, but the last thing I want is to start the car and it going nuts because timing is all off. I'll of course be running premium, but will stock timing be able to handle the HC?

pull some timing...better yet, buy (or borrow) a j&s safeguard...
get on a dyno with an experienced tuner and have them listen for the tell tale signs.

higher static compression will make the motor more prone to deto, but the bigger overlap on the cams means the dynamic compression will probably be (without checking the math), not a great deal higher than stock. The short rod ratio gives the motor an uncanny resistance to knock and a love of timing....but play it safe...run it a little rich, run it with a little less timing, and slowly feed it all back in. If you're not confident doing it, get a professional...a few hundred extra is a small price to pay when compared to blowing up a few grand's worth of investment.

 

[CulRidr]

So what's the difference between dynamic compression (which you say will be close to stock, ie: 9.1) and the actual compression of 10.X (not sure exactly due to the head being lightly decked)?

As for timing, even if I were to pull some back at open loop, the piggyback won't be able to pull any at WOT right? Does that mean I can't push it until I do that or...? Going to a dyno will be one of the first things I'll do once the engine is broken in, but I'll need to pull some timing before I break it in since breaking it in means putting some throttle to it...honestly it's the only thing I'm a little tentative about, and the only thing that really scares me about this whole deal. I'm super stocked about everything else...

 

[LordWorm]

So what's the difference between dynamic compression (which you say will be close to stock, ie: 9.1) and the actual compression of 10.X (not sure exactly due to the head being lightly decked)?

As for timing, even if I were to pull some back at open loop, the piggyback won't be able to pull any at WOT right? Does that mean I can't push it until I do that or...? Going to a dyno will be one of the first things I'll do once the engine is broken in, but I'll need to pull some timing before I break it in since breaking it in means putting some throttle to it...honestly it's the only thing I'm a little tentative about, and the only thing that really scares me about this whole deal. I'm super stocked about everything else...

dynamic compression is a little tricksy to work out...i've posted a calculator to do it previously - i'll go looking for it..

basiaclly static comp (the compression you get quoted on a new piston) is calculated assuming the valves are closed during the entire compression stroke - as 90% of people on this forum would know, this isn't the case - therefore some of the volume of air being compressed is reduced as the air is forced back out of open valves... so dynamic compression is always lower than static.

one of the advantages of high comp pistons is you can run bigger cams (more overlap, more duration, more lift - thereby reducing pumping losses and improving engine effeciency) and net the same, or close to the same dynamic compression.

 

[CulRidr]

right, so in other words, if I were to compare (dyno) my engine with all the mods except for the overlapping cams, and my engine with the overlapping cams, and were to compare the 2 dyno charts, I should see that the one without overlap would in fact have a higher value before the effect of the crazy cams right? (not a good explanation, but essentially the HP should be higher for the stock cams below say 4000rpm because you get the full effect of the high compression, whereas the aggressiveness of the cams would then overtake this effect with greatly improved flow...did I get that right, keeping in mind that the number is arbitrary?)

 

[LordWorm]

right, so in other words, if I were to compare (dyno) my engine with all the mods except for the overlapping cams, and my engine with the overlapping cams, and were to compare the 2 dyno charts, I should see that the one without overlap would in fact have a higher value before the effect of the crazy cams right? (not a good explanation, but essentially the HP should be higher for the stock cams below say 4000rpm because you get the full effect of the high compression, whereas the aggressiveness of the cams would then overtake this effect with greatly improved flow...did I get that right, keeping in mind that the number is arbitrary?)

little more to it than that...the increased engine effeciency, increased air, more fuel being burnt, better combustion, higher cylinder pressures etc outway the gain in actual compression. but in essense this is one of the reasons why adjusting cam timing moves your powerband up, down, back and forth....move overlap is needed for power in higher rev ranges - so without changing the compression, and only upping overlap, you make less power down low due to the loss in compression.

in theory (and all else being equal) increasing compression SHOULD increase power *everywhere*

I'll find some literature for you when i get done at work .

 

[CulRidr]

yes of course, but at a point where the cams aren't flowing like crazy but are overlapping (and therefore "leaking" power), a similar setup with no leaking should have a shade more power right? I don't really care for my setup since I want more power up top, but I'm just trying to understand the theory behind it. The twiggys/integrals don't flow much more then stock/FSZE under 4000rpm right?
And the nice thing about the cam gears should be that I could put the power of the twiggys way down where their near peak should be around 7000rpm rather then near 8000rpm right? making for more power in the lower rpm range...ie; having the crazy bump nearer to 3500rpm vs 4000rpm? I'm sure my numbers are off, and if you have more accurate ones I'd greatly appreciate it, but the idea is there right?

Thanks in advance for the literature, I'm sure I'll eat it up

 

[LordWorm]

yes of course, but at a point where the cams aren't flowing like crazy but are overlapping (and therefore "leaking" power), a similar setup with no leaking should have a shade more power right? I don't really care for my setup since I want more power up top, but I'm just trying to understand the theory behind it. The twiggys/integrals don't flow much more then stock/FSZE under 4000rpm right?
And the nice thing about the cam gears should be that I could put the power of the twiggys way down where their near peak should be around 7000rpm rather then near 8000rpm right? making for more power in the lower rpm range...ie; having the crazy bump nearer to 3500rpm vs 4000rpm? I'm sure my numbers are off, and if you have more accurate ones I'd greatly appreciate it, but the idea is there right?

Thanks in advance for the literature, I'm sure I'll eat it up

The cams will respond nicely to being brought down to a more street friendly range - they kick like a mule at around 4 to 5k rpm (the whole nature of the engine changes, the sound, the feel) and really start to sing about 6k..then you run into the rev limit...if you can get it down even 500rpm it would be awesome. Would also help pacify the idle somewhat.

your idea is sound - but to get accurate ideas about your combination, you have no choice but to put it together, dyno it, and see where it all takes you...thats the marvelous thing about engine rebuilds...theory is great, but all the theory in the world is no match for solid dyno time

 

[CulRidr]

I'll just have fun on the road to break it in and hear it sing (and groan on the highway...) before doing that. Glad to hear that my theories aren't completely off the wall for someone who doesn't know THAT much about engines...
I - and other surely - am very much excited at hearing what twiggys + custom header + MAM midpipe + Racing Beat catback will do for sound, but something tells me it's going to be beautifully rumbling... (band)

Again, looking forward to some more solid theory lessons...

 

[MakeMeGoFast]

dunno...maybe
you're not fiddling with the diagnostics system....you're tricking the computer into going open loop...only difference might be the shiney CEL light when you do it.

as i said, theory...i could be way off, wouldn't be the first time!

Are the ECU's the say? I've heard that OBDI ECU are easier to play around with.

 

[LordWorm]

Are the ECU's the say? I've heard that OBDI ECU are easier to play around with.

they are different
but the difference is mainly in the on board diagnostics system (though it does use different fuel and timing maps, different crank sensor etc).

What i'm saying is, that in theory, if you terminate the signal off of the o2 sensors, the motor's only remaining tool for fueling is open loop because its not getting the feedback to correct the fuel requirements.

on the OBDII computer, it'll probably throw a check engine light the second this occurs, but the computer will have no choice but to stop the motor running, or fuel according to fixed fuel tables...we already know that a dead O2 sensor doesn't shut the motor down...so we have to ASSUME that its fueling off of fixed tables....fixed tables that can be over-ridden by the piggyback.

 

[bidi]

3angle valve job 500

Some of your prices seam way too high, especially this one.
I realize there's a difference in currency, but are you getting those parts gold plated? You might be better off shopping around for a different shop... unless it's the only one in town, in which case I guess they have a monopoly.

My local shop replaced all valve and cam seals, replaced bent valves, installed an aftermarket camshaft, and did a 3angle valve job. They also milled the head, replaced a broken stud, and cleaned it to a poin where the head looked brand new... and all for $250.

I hope your build goes well, looks interesting (drinks)

 

[CulRidr]

those seals are pretty cheap, canadian currency, it includes a head milling, full cleaning, partial reinstallation, and a professional job. There used to be another place in town, but they closed years ago, so ya they essentially have a monopoly. If I find another reputable shop I might consider it, but right now I don't really have a choice

 

[CulRidr]

Holy crap my plans change quickly, but when you find deals, you got to take them. Looks like I'll be going with a used SpeedCircuit stage2 head. Anyone want to comment on it? The only thing I'd be a little unsure about is how much porting is actually done (loss of velocity?) and if there is enough roughness retained to keep some good turbulence for proper A/F mixture. I'm sure Dana knows what he's doing, but would appreciate some feedback if possible as I haven't seen much online.

 

[niky]

they are different
but the difference is mainly in the on board diagnostics system (though it does use different fuel and timing maps, different crank sensor etc).

What i'm saying is, that in theory, if you terminate the signal off of the o2 sensors, the motor's only remaining tool for fueling is open loop because its not getting the feedback to correct the fuel requirements.

on the OBDII computer, it'll probably throw a check engine light the second this occurs, but the computer will have no choice but to stop the motor running, or fuel according to fixed fuel tables...we already know that a dead O2 sensor doesn't shut the motor down...so we have to ASSUME that its fueling off of fixed tables....fixed tables that can be over-ridden by the piggyback.

Which is exactly how my car runs. Disconnected O2s.

The only advantage with OBDI is that you won't see a CEL, but this trick should work just as well on an OBDII car.

 

[LordWorm]

Holy crap my plans change quickly, but when you find deals, you got to take them. Looks like I'll be going with a used SpeedCircuit stage2 head. Anyone want to comment on it? The only thing I'd be a little unsure about is how much porting is actually done (loss of velocity?) and if there is enough roughness retained to keep some good turbulence for proper A/F mixture. I'm sure Dana knows what he's doing, but would appreciate some feedback if possible as I haven't seen much online.

speak to kooldino about exactly what is done... it *may* be over the top for NA but on the surface doesn't look like it'll be a big problem. I will stress that the problem with flow will still exist upstream of the head - the stock IM is going to hurt in this respect because the thing is only going to flow as well as its most restrictive component.

 

[CulRidr]

^Yup true, but if you get all the internals taken care of, then if all that is left is a bolt-on, it's not a big issue to swap over in comparison