Colt Cams

[Dallas Stace-smith]

I'm running an 03 Alh with sprint 520 nozzles and a Malone stage 1. Looking to get a new cam and want a colt. Just wondering what the difference between the stage 2 and the stage 3 colt Cams are and what you guys recommend?

 

[adamss24]

I would Say spend your money on a larger turbo and a bigger set of nozzles then tune it ! Budget for a better clutch and further down the line a 11mm pump…
All mods you have at the moment are not man enough for a performance cam and with cams you either get low/mid range performance or you get top end- no cam is performing well across the rev range- vw took its time and made sure that very little can be improved upon in economy stakes…

 

[Mozambiquer]

I'm running an 03 Alh with sprint 520 nozzles and a Malone stage 1. Looking to get a new cam and want a colt. Just wondering what the difference between the stage 2 and the stage 3 colt Cams are and what you guys recommend?

I've got a Colt stage two on my ALH with pp520 bosio nozzles, vnt17 and Malone stage 4 tune. It really lowers the egts and helps spool the turbo a bit faster.
I've got an extra lightly used stage two I'd sell for a good deal, if you want one.
The stage three you have to machine the head to get it to clear, whereas the stage one you can simply install in a stock head.

 

[Dallas Stace-smith]

I've got a Colt stage two on my ALH with pp520 bosio nozzles, vnt17 and Malone stage 4 tune. It really lowers the egts and helps spool the turbo a bit faster.
I've got an extra lightly used stage two I'd sell for a good deal, if you want one.
The stage three you have to machine the head to get it to clear, whereas the stage one you can simply install in a stock head.

Okay thanks alot

 

[derek5120]

Make sure you call them directly instead of going through a vendor. You are in Canada so you'll save shipping and exchange. Super nice guys to deal with, I've got stage 2. I will agree that your money would be better spent somewhere else, most people don't swap cams until they are reasonably modified.

 

[Dallas Stace-smith]

Yeah I'm not thinking of doing it right away, there are other things that I want to do first, I have always just wondered what the real differences were because there isn't that much of a price difference

 

[IndigoBlueWagon]

When I had the head ported on my ALH I used a Dbilas cam (similar to Colt). Before and after dynos were no different. Even the porting didn't help power output. As one tuner says, "with forced induction large orifices aren't your friends." I guess that applies to valve opening, too. My engine did best when it was all stock internally.

 

[Houpty GT]

When I had the head ported on my ALH I used a Dbilas cam (similar to Colt). Before and after dynos were no different. Even the porting didn't help power output. As one tuner says, "with forced induction large orifices aren't your friends." I guess that applies to valve opening, too. My engine did best when it was all stock internally.

It is sad but a properly tuned engine should show no power increase.

Matters of design:
Stock parts work well for stock parameters. There were small compromises made during manufacture for stock parameters. When exceeding stock parameters for power, there is room for gains. However a Diesel does not operate like a gasoline engine, which will automatically increase fuel with an increase supply of air. A Diesel works on fixed fuel and excess air. If you already have excess air, then more air will not increase power. To see power gains you either need to start off with excess fuel and smoke, or you need a retune or hammer mod.

Matters of testing:
I was aware of this before my cam and ported head. I took readings of EGT and datalogs of the mass airflow for before and after. It is unfortunate that Rosstech's glitchy software only took a single data points and gave me one worthless number for comparison of before.

Matters of results:
So I am only left with my arbitrary impression. The lower end feels more sluggish and the top end does not feel any more powerful. The low end decrease may be a function of the fact that smaller ports supply more air through higher port velocities for low RPM (pile driver effect). The high end may be a matter of the boost cutoff that Malone has in his tune. Rocket Chip could be a different story with more boost and no RPM cutoff. Repairs and more testing to follow.

Our Finnish friends make ~300 HP AHU and ALH with merely a ported head, turbo, nozzles, and tune.

 

[BustedBolts]

An aftermarket cam and/or head porting are only going to truly benefit you if you are exceeding or close to exceeding the head flow, which I personally believe is close to 250bhp. Otherwise spend you money on a gtb turbo, good injectors, and an intercooler setup.

 

[IndigoBlueWagon]

I've been around a lot of TDI dynos, and I'm not sure I've ever seen an ALH make over 250 WHP. Even 220 WHP is pretty rare.

 

[Houpty GT]

Busted Bolts might be right.
North Americans cannot compare with the exposure and availability of Diesel engines that they get in Europe. Thus we have less knowledge. There are fewer Diesel cars. There are fewer cheap Diesel engines in the junkyard. There are fewer Diesel drivers. There are fewer tuners, hobbyist, mechanics, and vendors who know about Diesel and they only do gasoline. Even this website FAQ says you can't boost over 18 psi so it is no wonder why we are behind.

"Do not operate an engine with a stock compression ratio at higher than 18 psi boost pressure under any circumstances."

 

[jwrb]

Busted Bolts might be right.
North Americans cannot compare with the exposure and availability of Diesel engines that they get in Europe. Thus we have less knowledge. There are fewer Diesel cars. There are fewer cheap Diesel engines in the junkyard. There are fewer Diesel drivers. There are fewer tuners, hobbyist, mechanics, and vendors who know about Diesel and they only do gasoline. Even this website FAQ says you can't boost over 18 psi so it is no wonder why we are behind.

"Do not operate an engine with a stock compression ratio at higher than 18 psi boost pressure under any circumstances."

Bloody hell, 18psi on a stock TDI.

I run 40psi (Holset HE200VG) on a stock block with just 12.9 headbolts

 

[[486]]

When I had the head ported on my ALH I used a Dbilas cam (similar to Colt). Before and after dynos were no different. Even the porting didn't help power output. As one tuner says, "with forced induction large orifices aren't your friends." I guess that applies to valve opening, too. My engine did best when it was all stock internally.

well, when the turbo itself is the restriction to flow you aren't going to make any difference with the cylinder head

also if you make an engine breathe easier you often gotta change the AFR in the smoke maps to see the full benefit of the extra air, especially with a pressure based set of maps

 

[terrydtdi]

I swapped my bottom end for another stock bottom end for now. To get a little more life out of the current bottom end I went back to 764 nozzles. I had R520's in there previously when I broke a piston ring, which then broke the piston. Always run it hard, along with a handfull of track days, and oh 420,000 miles on her. The other mods I do have right now are RC5+, a colt stage 2, ported head, double valve spings, 11mm, 17/22 turbo, 28PSI, 3 bar map, 764's, PD150 intake, 3" exhaust, bigger IC piping, VR6 MAF and Airbox.

What I'm getting at is, with the smaller nozzles I'm not smoking at all, the car looks like a gasser, I need bigger nozzles to match my air flow. So with fairly heavy mods the increased air flow apparently is working. Now appears to be starved for fuel. I do need to run some logs to see where I'm at.

 

[Mongler98]

Even this website FAQ says you can't boost over 18 psi so it is no wonder why we are behind.

"Do not operate an engine with a stock compression ratio at higher than 18 psi boost pressure under any circumstances."

Yea yea yea
Ran for 6 years at 27psi with no issues. Other than head lift from an overheat that causes a warp.
I've been told that 18 is a ( it will last forever) pressure. I was told that 24 to 28 is the magic stock numbers and that the block cant handle much more than 38 without modification

 

[PakProtector]

I would really like to see logs taken with EMP. I have a feeling that [486] is right on the money with his worry about smaller turbine sides. It is not like I am ever likely to start going nuts and trying it for myself, so there...LOL
cheers,
Douglas

 

[[486]]

I would really like to see logs taken with EMP. I have a feeling that [486] is right on the money with his worry about smaller turbine sides. It is not like I am ever likely to start going nuts and trying it for myself, so there...LOL
cheers,
Douglas

pull your pyrometer some time and stick a cheap industrial pressure gauge on a piece of 1/8" copper tube
compression fittings at either end
doesn't take much effort or investment at all

you'd be shocked at how high EMP can get with these tiny turbos, bad "well it drives okay so good enough" vane maps compound the problem something fierce

 

[PakProtector]

With no egr to worry about, one can build a much better map I think. Otherwise EGR opens, air goes out the exhaust and turbo speeds up...maybe catastrophically.

Coming around to the idea of trying to learn how to tune a bigger turbo...
cheers,
Douglas