Colt cams or other regrind bulk buy

[mikeseli]

Originally posted by Nuke
I've got a question: why $375 for one grind and $450 for another? Isn't it the same amount of material and labor for each grind, assuming both are re-grinding KL-03 cams? Most cam makers offer several different profiles at the same price.

You question is not clear, are you talking about $450 for the Colt Cams? If you read the post from the beggining then you'll understand why the extra cost.

Second, why would someone sell another grind for the same price, you need to take into account the r&d involved as well into the price.

[93PGT_Neal]

Originally posted by mikeseli


VRIS points is only a function of intake manifold design(runner length and runner diameter), and not going to be affected by other mods such as(cams, headers, exhaust, or even increase of block size). Therefore you shouldn't have a problem with your stock 03 VRIS points if you have a 03 intake manifold.

HOW MANY TIMES HAVE I STATED THIS IN PT, I think this is my 86th time.

What if you had a ported 03 manifold? Would that change the VRIS points also and yes i know that the increased air together with the cams would help more, but would i still need to have my ecu reprogrammed or since i changed the stats on my IM runners would this not be necessary.

[mikeseli]

Originally posted by 93PGT_Neal


What if you had a ported 03 manifold? Would that change the VRIS points also and yes i know that the increased air together with the cams would help more, but would i still need to have my ecu reprogrammed or since i changed the stats on my IM runners would this not be necessary.

Porting the 03 intake manifold by increase the size of the runner diameter will affect the VRIS points, but the affect will not be more than 100rpms, therefore I wouldn't bother.

A good mod to do is to add a fuel pressure regulator with your ported 03 manifold and a set of regrinded cams. Increase the fuel pressure will increase the gains even more in the middle and upper range of the rpms.

[Nuke]

Originally posted by mikeseli


You question is not clear, are you talking about $450 for the Colt Cams? If you read the post from the beggining then you'll understand why the extra cost.

Second, why would someone sell another grind for the same price, you need to take into account the r&d involved as well into the price.

Your posts aren't crystal clear either. Are you talking about $375 for cams you regrind and $450 for cams ground by Colt and sold through you?

Cam grinders and manufacturers sell similar cam patterns at identical prices. Different cam series get different prices (but not $125 different). The lifts/durations you're talking about aren't radically different from each other so I don't see the justification for the price difference.

[mikeseli]

Originally posted by Nuke


Your posts aren't crystal clear either. Are you talking about $375 for cams you regrind and $450 for cams ground by Colt and sold through you?

Yes. But I don't regrind my grind, a machine shop does the cam grinding, I just made the master(initial cam lobe) on CATIA(drafting software) then made a master with CAD CAM.

[David Coleman]

An FPR would clearly be a good mod with these cams, especially considering our ECU coding at the higher RPM's. Do you think these cams would necessitate exhaust piping larger than 2.5"? Just a thought I had, whilst trying to figure out what I'm going to do about my 1-7/8" crush bent stock piping. Even with the KL01 cams, the ZE isnt liking it much...

[mikeseli]

Originally posted by David Coleman
An FPR would clearly be a good mod with these cams, especially considering our ECU coding at the higher RPM's. Do you think these cams would necessitate exhaust piping larger than 2.5"? Just a thought I had, whilst trying to figure out what I'm going to do about my 1-7/8" crush bent stock piping. Even with the KL01 cams, the ZE isnt liking it much...

Dave, stay with an exhaust of 2.25" or 2.5". I would personally stay with a 2.25" mandrel bent, with a straight thru design muffler. Also a straight thru design resonator will be required to quiet down the system. If you're going to use nitrous go with a 2.5" mandrel bent exhaust. A 2.25" exhaust system is good up to 204whp@7000rpms without sacrificing any power. Most of the people in PT and in the performance industry don't know or understand fluid dynamics. When you design an exhaust system you need to look peak hp @ given rpms, also you need to look into a engines redline. An engine that makes peak hp of 200whp@5000rpms needs to use the same exhaust as an engine that makes 140whp@8000. Does this make sense.

[Adlorin]

Okay well i'm confused and maybe you need to say it, a different way for the 87th time (*). I am American after all.

This is for a 03 engine, and 03 IM.

O3 Cams peak @ 5500, vris closes at 6250;
Which is fine.

your cams peak @ 6750, vris closes at 6250;
Which leads me to think we aren't getting the best we can get..

Being the peak is above the vris, and vris closing will suffocate air flow; why would we NOT want to have the vris stay open till 6800 like you said earlier? But then you said with 03 IM you wouldn't advise changing the vris close points beyond stock..

~Patrick

Originally posted by mikeseli


VRIS points is only a function of intake manifold design(runner length and runner diameter), and not going to be affected by other mods such as(cams, headers, exhaust, or even increase of block size). Therefore you shouldn't have a problem with your stock 03 VRIS points if you have a 03 intake manifold.

HOW MANY TIMES HAVE I STATED THIS IN PT, I think this is my 86th time.

[mikeseli]

Originally posted by Adlorin
Okay well i'm confused and maybe you need to say it, a different way for the 87th time (*). I am American after all.

This is for a 03 engine, and 03 IM.

O3 Cams peak @ 5500, vris closes at 6250;
Which is fine.

your cams peak @ 6750, vris closes at 6250;
Which leads me to think we aren't getting the best we can get..

Being the peak is above the vris, and vris closing will suffocate air flow; why would we NOT want to have the vris stay open till 6800 like you said earlier? But then you said with 03 IM you wouldn't advise changing the vris close points beyond stock..

~Patrick

Patrick, VRIS is a function of intake manifold design. Check this site, you might understand the concept of VRIS:

http://www.geocities.com/mikey9t6/car_uvwxyz_vris.htm

[Adlorin]

Hmm after reading it, I am still consfued as what you recomend. If going to a cam regrind such as yours, keep the vris close point at stock or raise it to compensate for the cam's?!

"The big problem with the VRIS is at 6500 RPM +. The engine computer shuts the butterfly valves, severely restricting airflow. For atmospheric air, the secondary resonance pulses would help charge the cylinders, but with forced induction, the high density air being force through these passages will not be able to achieve the secondary resonance, and will lose a lot of pressure trying to squeeze through the restrictive passages. The only way to get around this problem is through some ECU reprogramming to keep all the butterfly valves open at high RPM's"

So given this and the peak is during the vris close points, 'severely restricting airflow' why would you want the VRIS to close before peak and ruin it?!

Originally posted by mikeseli


Patrick, VRIS is a function of intake manifold design. Check this site, you might understand the concept of VRIS:

http://www.geocities.com/mikey9t6/car_uvwxyz_vris.htm

[halfriceboy]

Originally posted by Adlorin
Okay well i'm confused and maybe you need to say it, a different way for the 87th time (*). I am American after all.

This is for a 03 engine, and 03 IM.

O3 Cams peak @ 5500, vris closes at 6250;
Which is fine.

your cams peak @ 6750, vris closes at 6250;
Which leads me to think we aren't getting the best we can get..

Being the peak is above the vris, and vris closing will suffocate air flow; why would we NOT want to have the vris stay open till 6800 like you said earlier? But then you said with 03 IM you wouldn't advise changing the vris close points beyond stock..

~Patrick

you can also just tie open VRIS 2, right?

[mikeseli]

Originally posted by halfriceboy


you can also just tie open VRIS 2, right?

Can someone help me out, am I speaking english here????

If you have an 03 intake manifold and an 03 ECU don't play with the VRIS, they're fine as is. Who ever thought that keeping VRIS#1 or #2 tied open will produce more power is an moron. If you slap on cams with more duration do not alter or play around with your VRIS points, they're fine as is. If you don't beleive why don't you dyno test this yourself (the graphs don't lie)

If you have a ZE intake manifold than your 03 VRIS points are incorrect. I can get you a EPROM with ZE VRIS points but the rest is 03(check out the bulk section for more details).

Having your VRIS closed doesn't restrict airflow, it just rederects it to a different path that is more efficient at that rpm range. I hope this is clear. If not I'll say the same thing is French, Italian or even Greek.

[Adlorin]

Si, hablo español? Okay I re-read your page and I *think* I understand better now, thank you. I just remember you saying if the vris stayed open longer, for the peak of the cams - it would improve peformance. Maybe it was just that you were refering to having jspec cams and jspec IM, but having the vris working at US IM settings. Correct?

If no mods need to be made to ECU, just basic intake/exhaust work; your grind will make 20hp at peak over stock as i understand; that is even with vris closing at 6250 - when the cams peak at 6800. Is this correct? If so, very cool and I understand it correctly now.

Thanx again.

~Patrick

Originally posted by mikeseli


Can someone help me out, am I speaking english here????

If you have an 03 intake manifold and an 03 ECU don't play with the VRIS, they're fine as is. Who ever thought that keeping VRIS#1 or #2 tied open will produce more power is an moron. If you slap on cams with more duration do not alter or play around with your VRIS points, they're fine as is. If you don't beleive why don't you dyno test this yourself (the graphs don't lie)

If you have a ZE intake manifold than your 03 VRIS points are incorrect. I can get you a EPROM with ZE VRIS points but the rest is 03(check out the bulk section for more details).

Having your VRIS closed doesn't restrict airflow, it just rederects it to a different path that is more efficient at that rpm range. I hope this is clear. If not I'll say the same thing is French, Italian or even Greek.

[mikeseli]

People this is not rocket science, even if I work for the aerospace industry.

If you have an 03 IM stick with the 03 VRIS points, Mazda engineers knew what they were doing. The only mod that's going to affect the VRIS points is if you turbocharge or supercharge the engine. Any other mod you to the engine won't affect the existing VRIS points, they are perfect as is.

If you have a ZE IM then you need it's VRIS points and not the 03 VRIS points. The ZE IM VRIS points are located at much higher rpms.

ZE VRIS points: (4050,4800,6800)
03 VRIS points: (3250,4250,6250)

Therefore if you have a ZE IM you need to have both VRIS open 'til 6800 instead of 6250. Between 6250 and 6800rpms there's lots of power to be had.

[David Coleman]

Originally posted by mikeseli


Dave, stay with an exhaust of 2.25" or 2.5". I would personally stay with a 2.25" mandrel bent, with a straight thru design muffler. Also a straight thru design resonator will be required to quiet down the system. If you're going to use nitrous go with a 2.5" mandrel bent exhaust. A 2.25" exhaust system is good up to 204whp@7000rpms without sacrificing any power. Most of the people in PT and in the performance industry don't know or understand fluid dynamics. When you design an exhaust system you need to look peak hp @ given rpms, also you need to look into a engines redline. An engine that makes peak hp of 200whp@5000rpms needs to use the same exhaust as an engine that makes 140whp@8000. Does this make sense.

Mike, calculating for 60hp/in^2 for piping cross sectional area [a bit on the high side] and 250hp [a bit on the high side] I only got ~2.4" ID. So your numbers make perfect sense. I'll probably go with 2.25 or 2.5 with a 24" straight through resonator [drilled core glass pack or maybe the Moroso Spiral Core] with a chambered muffler, cause I want to keep this thing as quiet as possible and not have the notorious K series 3k RPM drone. Yes Mike, I sure understand, but maybe that's cause I'm studying Mech. Eng. at University.