"Best" cams on VR6T

[FishWick 21]

I'm hearing a lot of praise of DG Autotech's cams - http://www.dgautotech.com/dgauto/

No one that I know of has done a back to back comparison of several cams on a VR6, so it's hard to make an informed decision.

Or there's the usual suspects but I'm not getting into a churlish debate about them again, you pays your money and takes your choices :-)

[matty.vrt 120]

I have been running my vr6 turbo for over a year now at 1.6 bar with standard cams and I find they perform too well to justify replacing with performance ones especially when I could add 1-2 psi more and add the same power that a set of cams would add. Maybe if I was rebuilding my motor with all new rods and pistons I would be tempted to drop some in there. I totally agree with kev no one has done back to back tests so fit the ones you think look the best and enjoy the results.

[FishWick 21]

Try some cams mate, you might be surprised :-)

It's not just the boost, forget that. Boost is boost. It's all about flow. More flow = More power. ON and OFF boost. Cams really wake up the bottom end a lot. As a test a couple of years ago, I took my SP cams out and put the standards back in, no other changes. It felt like the rear calipers were stuck on it was so much slower....

[matty.vrt 120]

I think i will try some then. i had a set if drc 268's on my supercharged vr6 that were ok but i must have got a bad set and after trying 2 sets of genuine cam followers i could not stop them making a loud tappet noise as if it had solid followers in.

[powernut 1]

I think i will try some then. i had a set if drc 268's on my supercharged vr6 that were ok but i must have got a bad set and after trying 2 sets of genuine cam followers i could not stop them making a loud tappet noise as if it had solid followers in.

Hi matt did u replace valve springs as i hear a fair amount say they need to be replaced.(another exspense)bit im confused off is .when i sau which cams .as im thinking if i go from stock to say 268 or 275 im told the head will need a stage 3. .ie valves re skiming and pistons machinceing?little confused tbh as theres that many storys about unless kev might be able to help

[powernut 1]

Also say im runing 30psi on a stock cam and 30psi on lets say 268 cam .what is the differnce if your engine is still boosting at the same psi.

[FishWick 21]

The net result is more of the flow from your 30psi will get into the cylinders and you'll get a bigger bang.

You do your own mapping like I do and as you've seen for yourself, the fuel map shape follows the engine torque curve. I guarantee if you put 268s in, you'll have to plump up the 6000rpm + load sites wider than 50% throttle :-)

If you compare a stock intake + stock cam VRT to a short intake + cam'd VRT, the stock VRT torques up a little sooner in the midrange, but it also falls away fairly quickly - depending on turbo sizing and other factors. The shorty + cams keeps the torque curve flat from peak torque right over to the limiter. That top end grunt is what you need to dick on M3s etc, and I'm talking about the V8 M3s and modest boost too, < 15psi from a 35R.

Don't get me wrong, more boost is effective too, but it's more strain on the pipework and fittings etc, I just prefer the lesser boost more flow approach. Each to our own :-)

Yes, defo do springs, titanium caps etc, anything to lighten the valvetrain weight and help revs. Schimmel do a nice +1mm valve set made of inconel, works a treat with nice cams, 268 or 263 etc.

[powernut 1]

Well kev im not up on everything regards tuning .as im still doing plenty of reading what i can take in tbh . Me and my friend tunies .as it seems better to see whats going off on screen .then risking dynos if things arnt set up .something like;) ive just on with building a spare head up with better springs etc but .ive hit a slight problem .as i turn the cam onto its lobe faceing downwards its locking .meaning feels like its hitting the steam seal. Also i measured the amount of valve drop and ill need to machine the pistons too. But ive a idea that might work .im happy with intake temps in boost low compaired to stock intake

[powernut 1]

The net result is more of the flow from your 30psi will get into the cylinders and you'll get a bigger bang.

You do your own mapping like I do and as you've seen for yourself, the fuel map shape follows the engine torque curve. I guarantee if you put 268s in, you'll have to plump up the 6000rpm + load sites wider than 50% throttle :-)

If you compare a stock intake + stock cam VRT to a short intake + cam'd VRT, the stock VRT torques up a little sooner in the midrange, but it also falls away fairly quickly - depending on turbo sizing and other factors. The shorty + cams keeps the torque curve flat from peak torque right over to the limiter. That top end grunt is what you need to dick on M3s etc, and I'm talking about the V8 M3s and modest boost too, < 15psi from a 35R.

Don't get me wrong, more boost is effective too, but it's more strain on the pipework and fittings etc, I just prefer the lesser boost more flow approach. Each to our own :-)

Ps kev im unsure how do i manage less boost but more flow. I have another block here bored to 83.01mm but didnt really notice mutch differnce tbh. So just forged a stock 2.8 instead.might have been because the head was stock unsure tbh. Ive a timing question im noticeing when i floor the revs in say 4th gear turbo takes a fair bit to spool .below 100kpa on the map. Im woundering if i can risk advanceing it .a few degree.without any possible knock..as i use to have a 24v with no vvt but with a 12v timing map and killed 3 pistons with det.i blame camshaft s were too retarded.

[FishWick 21]

Yeah ignore bore on the 12V, makes very little difference with boost. Need to get more air into the cylinders, you need bigger valves and decent cams, or just turbo an R32 motor :-)

Yeah you can add more timing in the 100KPA load site. I'm crusing at ~45 deg from 30-60KPA above 3500rpm, 36 deg 60-80KPA 33 deg 90-100KPA, then mid 20s in boost with no det.

VRTs like lots of cruise timing to keep EGTs down.

With a short runner, low comp and non-projected spark plugs (Bosch F5DPOR are fantastic) you can run schitt loads of timing and keep them EGTs low and improve off boost responsiveness.

Standard 12V timing map has very low timing mate, I'm surprised that killed your 24V. Was it the rear bank that died? Were you using the 24V intake and what compression was it?