Inlet Cam For Mi On Std 2 Row Management

[philfingers 5]

I was speaking to someone recently and he has a PeterT inlet cam (St I I think) in his Mi. He was saying what a difference it's made to the car.

 

What's the difference between this and the catcams 526 inlet cam.

Basically the car is used for road rallying and so has to stay on std manifold and plenum. It's going on 2 row management (unless i can find a 3 row). What would be the best cam to go with for this setup. Idle isn't so much of an issue but I don't want to loose any bottom end grunt. The midrange the peterT gives sounds beneficial. I don't want all the gains at the top end.

Any suggestions welcome!

 

Phil

[philfingers 5]

anyone willing to comment on these or any other cams for that matter? Had a look through some threads and some say it's not worth fitting an inlet cam. Anyone wish add something?

 

Phil

[Anthony 1,003]

I've not driven a car with a Petert inlet cam so I can't comment on that.

 

I've driven three with a Catcam 526, and on all of these only seemed to be a noticeable improvement over standard above 5k rpm when it came "on-cam". From my experience, I suspect that this is not what you are looking for - works well enough on track when you can keep the revs up though, and is tractable from idle. I didn't personally time the cams up on any of them, so I don't know whether the cam timing is optimal or whether further advancing the inlet cam would bring the powerband down to where you're looking for.

 

What it might be worth trying first of all is sticking with standard cams and advancing the inlet cam a few degrees (fit a #4 pulley). In my experience that gives you a noticeably stronger midrange at the expense of a couple of hundred rpm at top end, and would, I imagine, work well for road rallying where you want a good spread of power.

[Stu 18]

You know my thoughts Phil, i quite like the PeterT Stg 1, i do often wonder if it might be worth getting a vernier on it though and verifying that its timed up bang on, im using a No.4 pulley too..

 

The timing pegs are ok, but using them is hardly an *exact* science and you could spend ages pissing about with the belt tension to get them cock on..

 

Theres nothing like enough play in my set to be a tooth out on any pulley so i figure its about as good as its gonna get.

[skeggyrik 3]

Stu on here has a PeterT inlet fitted.

 

M@tt and easy pug have had the cat cam inlet fitted to their Mi's in the past.

That particualr cam now lives in my Mi head, but I've not got the lump back in yet.

 

Might be worth contacting them?

[philfingers 5]

Well it's actually Stu's I'd seen. I'm running an No 4 exhaust and no 2 inlet at the moment. So would a 4/4 be a better option? You're right Anthony i do want mid range and I'd happily have more at the expense of loosing a bit at the top end. So I'll stick with std cams just now. I block skim would be a better option but I don't want to go down that route just yet. Though that would give an increase in power all the way through I suppose.

I'll see if I can get hold of another No4 to go on the inlet if this is a good option. I did a lot of searching on the pulleys when i was doing the belts and I was under the impression the preferred option was 2 inlet and 4 exhaust. but I definately prefer better midrnage and if a 4 inlet gives me that then maybe I'll go donw that path.

Thanks for your help guys,

 

phil

[Jon_Bmw 13]

This is an interesting topic as its my next 'upgrade' I think. The problem I have is this:

 

My car is already very lively at the top end of the spectrum, it really only comes on at 5000rpm BUT pulls and still makes power at 7100rpm. It is not dipping. Search under my name, I posted the graph on a thread somewhere to see it.

 

The engine is a D6C(i think) running 2 row management. It has a number 4 pulley on the inlet and the only mods are(to make it fit into the engine bay) are a crap K&N which seems to small and a NON split 2.75-3" exhaust which is probably loosing me some midrange.

 

Now this is only a track car really, <3000 miles a year job, so i am happy to have the power at 5000-7000rpm and it matches in with the 1.6 box nicely.

 

So the problem: Will a Peter T or a catcams inlet cam push the power band even higher!?! Where it is at the moment is fine, but if it didn't 'come on cam' until 6000rpm it would be useless with a 7100 limit.

 

Thoughts?

[welshpug 1,661]

reading on Peter's website it seems that there's no major change to the characteristics until 4.5k, where the torque really picks up over a standard cam, IF timed up correctly.

 

IMO its silly to mess about with different numbered pulleys and taking them on and off all the time, the belt isn't designed to be re-tensioned, so just fitting a vernier will save a lot of time.

 

http://www.taylor-eng.com/xu9j4/16v_camtiming.htm

[kyepan 291]

I was speaking to someone recently and he has a PeterT inlet cam (St I I think) in his Mi. He was saying what a difference it's made to the car.

 

What's the difference between this and the catcams 526 inlet cam.

Basically the car is used for road rallying and so has to stay on std manifold and plenum. It's going on 2 row management (unless i can find a 3 row). What would be the best cam to go with for this setup. Idle isn't so much of an issue but I don't want to loose any bottom end grunt. The midrange the peterT gives sounds beneficial. I don't want all the gains at the top end.

Any suggestions welcome!

 

Phil

can only comment on the stage 1 peter t cam, running on 3 row with his chip and a number 4 pulley. the chip went in first, and that gave a touch more instant throttle response, and also stopped it stalling when cold in the wet. The cam went in next and once it settled (or i learnt how to drive it) it freed the engine up noticably, it now rev's cleanly to the red line in first, before acceleration tailed off past 5k, that might be the pulley and the cam as it was on number 2 before. My car has and still does develop a very linear power delivery when 2 up, however with just me in the car, a surge is noticable when it comes on cam that was not there before, you can feel it in 2nd and 3rd where you have to hold on to your hat (and the wheel). Both batfink and baz have been in my car before and after, and DrSarty drove it briefly at the weekend.

 

cheers

 

J

[nick 3]

The biggest difference I have noticed with the PeterT inlet is the mid-range. I don't feel as though their is much gain at the top end but it pulls hard from 2 grand upwards, with another big push at about 4 grand all the way to the rev limit. I can dawdle along at 30 in fifth when I'm not in the mood and it will pull cleanly and quickly without changing down (this is without the divider in the downpipe which is supposed to rob torque) I have tried the chip, but it didn't seem to make any appreciable difference, so I have gone back to std, but may try it again as I had a few "new conversion niggles"

 

CRF450 drove it at the weekend and summed it up well.... "very willing, eager..."

 

Nick

[John_B 11]

My current Mi (Dave Walker's old engine, std cams with verniers, 45 jenveys and emerald ecu) doesn't really feel any faster than my old one (rebuilt engine, std apart from catcams inlet #4inlet #2exhaust). We haven't put the current one on the rollers yet so can't say for sure but in my opinion you definitely don't lose much low down with the catcams inlet. My opinion of the catcams cam has definitely gone up since the swap. The power does come in at 4500 rather than 4000 but not necessarily from a lower level. Of course I am comparing a rebuilt engine with one that's done 100,000 hard miles! The rolling road will tell.

Edited November 26, 2008 by John_B

[John_B 11]

The biggest difference I have noticed with the PeterT inlet is the mid-range. I don't feel as though their is much gain at the top end but it pulls hard from 2 grand upwards, with another big push at about 4 grand all the way to the rev limit. I can dawdle along at 30 in fifth when I'm not in the mood and it will pull cleanly and quickly without changing down (this is without the divider in the downpipe which is supposed to rob torque) I have tried the chip, but it didn't seem to make any appreciable difference, so I have gone back to std, but may try it again as I had a few "new conversion niggles"

 

CRF450 drove it at the weekend and summed it up well.... "very willing, eager..."

 

Nick

 

Is this compared to standard or to the catcams Nick?

[nick 3]

Compared to std.

[philfingers 5]

well I screwed up a wee bit. I have infact No4 inlet and No2 exhaust, which is the opposite to how the engine came to me. As mentioned before I did a lot of research into the pulleys and set it to how the majority reckoned it should be and in fact it's setup how folks have said, 4 on the inlet. Vewrdict is still out really. I have never even driven an Mi16 before. The car was running a GpA 8v and was cammy and hence the reason to go for a tractable 16v which probably makes more power as std. The 8v got 61st and 63rd on the Mull rally so it was no slouch. It will run with a 1900/4.4 box initially but I do have a 4.8 to go in at some point. I think I'll get it running first and see if I need anymore power. It's got the GTi6 sump, windage tray, pump chain and pulley, spacer etc so hopefully oil surge won't be an issue

I think I'd still rather go with a 3 row map. Engine due to go in this w/e

 

Phil

[Stu 18]

Sweet as mate, ive got a similar sump setup as you know, and ive recently fitted a 25psi tell-tale oil pressure switch and light now and had no surge at Donnington on sunday.

 

Admittedly, it was a little damp so couldnt 'really' press on; but a few glances at the gauge during some of the faster corners didnt give me cause for concern...

[James_m 0]

Personally, i feel the petert stage 1 cam did little for my car which i find odd considering other peoples findings.

With the stock cam my car was very strong from 4-6.5k with a bit off tail off before the rev limiter.

With the the different inlet it felt flatter all the way to about 5k where it then goes ok and pulls all the way to about 6800 before tailling off.

In a drag race id be suprised if it was any quicker to be honest as the gains felt minimal.

That was with 4 inlet 2 exhaust.

[petert 588]

Personally, i feel the petert stage 1 cam did little for my car which i find odd considering other peoples findings.

With the stock cam my car was very strong from 4-6.5k with a bit off tail off before the rev limiter.

With the the different inlet it felt flatter all the way to about 5k where it then goes ok and pulls all the way to about 6800 before tailling off.

In a drag race id be suprised if it was any quicker to be honest as the gains felt minimal.

That was with 4 inlet 2 exhaust.

 

 

In defence of my Stage I Mi16 cam, there have been very few unsatisfied customers. This is only the second in fact. There are a few possible reasons why it didn't perform for you.

 

a. Poor compression - if compression is low for what ever reason, no aftermarket camshaft is going to perform any better than the standard one.

 

b. Incorrectly Timed - I've never said this publicly, but here's one of the secrets to its success. The cam is ground one degree advanced, so it's perfectly timed when used with a #3 pulley and an otherwise standard block/head. This equates to 0.065" lift at TDC. If you use a #4 pulley, you'll have more lift at TDC, with a #2 less. If the block or head has been skimmed the figures will change. It's the engine builders responsibility to check the lift at TDC.

 

With most installations, it's stronger from 3000-3500 onwards. I'm certainly not going to say it's stronger than a std. cam under 3000, because it isn't. You can't get something for nothing.

 

I'm not for one minute suggesting it's the best cam on market, but it's certainly the best value for money if 180-185hp is your aim.

 

My preferred setup for the exhaust cam is to RETARD it, so it has also has approx. 0.065" lift at TDC, rather than the standard 0.032" (with #2 pulley). This is easily achieved with an offset key. That's how the engine is setup on this page: http://www.taylor-eng.com/ecu/motronic_intro.html

which runs hard to the 7500 limit.

Edited December 3, 2008 by petert