Anyone got experience with N/A cars and sports cams etc?

[Leeds_finest]

As above..

[Nealevo]

If its non volvo cars, i used to have a golf mk2 gti 16valve with kent cams, cant remember the duration off the top of my head, but it had a lumpy idle, but hit 5000 rpm and all hell used to break loose, it was running 180 bhp with other mods and it went well.

[Leeds_finest]

If its non volvo cars, i used to have a golf mk2 gti 16valve with kent cams, cant remember the duration off the top of my head, but it had a lumpy idle, but hit 5000 rpm and all hell used to break loose, it was running 180 bhp with other mods and it went well.

Only reason I ask is, i'm currently running a Newman Cam (8v single cam) in my VW Polo. The spec sheet says it's a phase 3 'tarmac rally' cam, power band 3-7.5k revs.

I now know that for a road car, this cam is a bit OTT and in fairness I didn't choose this cam as such, I bought it as a bundle with a P/P cylinder head and vernier pulley second hand.

It doesn't pull until at least 5-6k which is when I would expect an 8v engine in a car like this to start winding down really. Certainly doesn't perform as the spec sheet says it should.

My question is:

If I went to a phase 1 cam etc, something less lairy, would my car be faster overall?

My reasoning is - by the time the power comes in hard, I have had at least 4-5k of gutless/flat driving. It's actually bordering on dangerous for the engine revving it as hard as I have to in order to get the power out of it. Surely if I put a cam in there that didn't produce quite as high peak power figure, but the power came in earlier and stayed for longer, surely it would be quicker overall.

Thoughts?

[Nealevo]

having owned many an 8 valve mk2 gti i would suggest changing the cam, when i used one i think it was a piper the power came in about 3000rpm and it was a clean hike all the way to 5500 ish, so with the other mods you have ( reading a thread somewhere about your polo) i think it would perform much better without stressing the engine too much, and give you more drivability, which is what an 8 valve is all about.

[I want a T5]

Only reason I ask is, i'm currently running a Newman Cam (8v single cam) in my VW Polo. The spec sheet says it's a phase 3 'tarmac rally' cam, power band 3-7.5k revs.

I now know that for a road car, this cam is a bit OTT and in fairness I didn't choose this cam as such, I bought it as a bundle with a P/P cylinder head and vernier pulley second hand.

It doesn't pull until at least 5-6k which is when I would expect an 8v engine in a car like this to start winding down really. Certainly doesn't perform as the spec sheet says it should.

My question is:

If I went to a phase 1 cam etc, something less lairy, would my car be faster overall?

My reasoning is - by the time the power comes in hard, I have had at least 4-5k of gutless/flat driving. It's actually bordering on dangerous for the engine revving it as hard as I have to in order to get the power out of it. Surely if I put a cam in there that didn't produce quite as high peak power figure, but the power came in earlier and stayed for longer, surely it would be quicker overall.

Thoughts?

Intake and exhaust mods compliment the cam? Cam timing set up properly?

I had a Mk1 Escort with a lairy Kent Cam and ended up with twin 40s and a 4-1 exhaust. That didnt come on song until around 5k when I first set it up. With a change to a 4-2-1 exhaust, the power shifted to lower down the rev range albeit with a sacrifice of top end power.

[Tomcat]

I've heard before of cars running realy wild cams that have run mangement systems and throttle bodies that ran really quite well, gone are the days of lumpy cams that barely tick over.

[Kingsford G]

Had one on mk2 golf,lumpy idle but after about 4500rpm pushes to the seat.Make alot of diff.

[Leeds_finest]

Quick one for you guys (food for thought) - i've been told that to get the most from some lairy cams, you need to raise compression, what you guys think? I'm running standard comp at the moment but plan to raise it when I change cam.


having owned many an 8 valve mk2 gti i would suggest changing the cam, when i used one i think it was a piper the power came in about 3000rpm and it was a clean hike all the way to 5500 ish, so with the other mods you have ( reading a thread somewhere about your polo) i think it would perform much better without stressing the engine too much, and give you more drivability, which is what an 8 valve is all about.

Thanks, will consider Piper next time then.

Mine behaves VERY strangely. From what I can gather from friends, cams should come in smoothly but noticeably. I also expect even a 272 cam like mine to come in mid range.

BUT, mines very odd, the power graph suggests it's a smooth curve until peak power but it really isn't. It's relatively flat until it gets to around the 6,500 rpm mark and then the crossover is as clear cut as a Honda VTEC, no word of a lie. The engine note even has a clear crossover from 8v 'scooby like' gargle/growl to a high pitched scream. It's instantaneous and last until about 8,000 rpm where I back off due to not wanting to 'wang a rod'.

As standard, the engine revs to just 5,500 rpm and limits under fuel injected ECU. Mine now runs free of ECU and that's how I can get to 8,000 rpm but I know it's not safe and I rarely take it that far.

In fairness, I do have additional cooling mods in place, so higher revving is acceptable, but still, 8,000 rpm is excessive.


Intake and exhaust mods compliment the cam? Cam timing set up properly?

I had a Mk1 Escort with a lairy Kent Cam and ended up with twin 40s and a 4-1 exhaust. That didnt come on song until around 5k when I first set it up. With a change to a 4-2-1 exhaust, the power shifted to lower down the rev range albeit with a sacrifice of top end power.

These are just the main mods:

1. Four inline motorbike carburettors with approx 38mm throttle openings (custom inlet manifold).
2. Dyno jet kit.
3. Ported and flowed cylinder head (standard size valves).
4. Four branch exhaust manifold with custom exhaust system.
5. Adjustable valve timing gear.
6. Adjustable fuel pressure regs.
7. Adjustable ignition timing.

It's been in three times for cam/ignition timing and fuel adjustment. The answer I get everytime is "i'm sorry but the cam is just too peaky for what you're after".

I just need a new cam I think, i'm seeing a re-curring pattern here and that pattern involves 'kent' and 'piper' lol - i've been told Newman (which is what i'm using) don't always do what they say on the spec sheet :(


I've heard before of cars running realy wild cams that have run mangement systems and throttle bodies that ran really quite well, gone are the days of lumpy cams that barely tick over.

Hmmm I agree, the cam according to the spec sheet really isn't that over the top, but i'm guessing it doesn't perform as the spec sheet indicates.

I don't run management and throttle bodies to be fair, I run a more primitive version but the same principle of a single throttle PER cylinder i.e. motorbike carbs. I can however adjust fuel mixture, fuel pressure, ignition timing and valve timing so there's no excuse for a bad setup on my car lol :)


Had one on mk2 golf,lumpy idle but after about 4500rpm pushes to the seat.Make alot of diff.

Everyone I seem to speak to has nothing but praise for aftermarket cams, but mines just poo.

What make was yours? Any spec?

[I want a T5]

what comp ratio are is standard? (I'm unfamiliar with this engine but I guess the theories will remain constant). I think I was running about 9.5 to 1 but I cannot be sure as it was 20 years ago.....

I guess you will need to be real carful not to start getting detonation caused by too high a comp ratio as this will undo all your hard work!

[Leeds_finest]

what comp ratio are is standard? (I'm unfamiliar with this engine but I guess the theories will remain constant). I think I was running about 9.5 to 1 but I cannot be sure as it was 20 years ago.....

I guess you will need to be real carful not to start getting detonation caused by too high a comp ratio as this will undo all your hard work!

As you say, i'm sure my Polo is around that mark (9.5:1 ish).

I'll be certain to have somebody else do the actual setup in order to avoid any detonation problems etc, i'm fairly certain it's safe though, the old Skoda Felicia rally car uses the same engine as mine (obviously significantly more powerful than mine) and they run 12:1 I think.

Also, somebody abroad runs the same engine and even the exact same cam... but in an earlier Polo shell. He runs something like 11.5:1 I believe and his hasn't blown up even after 40,000km of thrash... or so he says ;)

[Nealevo]

As you are midlands based, try Aldon automotive in brierley hill, very good with carbs etc and rolling road setup, these are the people who set all my golfs up x4 and my pug 205 with mi16 on bike carbs,

But it does sound like your cam is to lairy!!

[Leeds_finest]

As you are midlands based, try Aldon automotive in brierley hill, very good with carbs etc and rolling road setup, these are the people who set all my golfs up x4 and my pug 205 with mi16 on bike carbs,

But it does sound like your cam is to lairy!!

Originally it was a toss up between Hi-Tech and Aldon. My dad told me to go to Aldon as he has a classic Lotus but my mates said go to Hi-Tech.

After a quick call to both, I was forced to go with Hi-Tech as Aldon told me that they didn't set up motorbike carbs i'm afraid :(

Plus, Hi-Tech have done a good job I just think it's the cam as you say.

[Leeds_finest]

MINI UPDATE:

The technical chap at Kent Cams exchanged a few emails with me earlier. I sent him the current specs of my Newman cam.

He said that they don't make a cam that will fit my engine because they only make Golf and Scirocco ones, and the casting is different apparently.

However, he said he could grind the spec of their 'GS1H' cam into my existing cam, so instead of making a completely new one they would essentially modify my existing one. Cost was around the £140 including return postage I believe.

I was hoping he would go into the nitty gritty of tech spec, but he didn't, he simply said that the spec of their 'GS1H' which is essentially a fast road stage 1 sort of cam would be better than my existing one. I think it's something like a 266 as opposed to my current 272.

Ed

[Nealevo]

That gs1h cam is what I had in my 16v golf, see first post, that are a good starting point, I think it was something like 20 ish bhp from just the cams, prob be about 10-12 for 8 valve engine as yours but much more drive able

[Leeds_finest]

That gs1h cam is what I had in my 16v golf, see first post, that are a good starting point, I think it was something like 20 ish bhp from just the cams, prob be about 10-12 for 8 valve engine as yours but much more drive able

I think they may call the twin cam equivalent something slightly different, although i'm sure it's the same spec/duration/lift etc.

I'll more than likely go for that one to be fair. My problem is, with my current cam, I can't keep it in the power band. In order to keep it in a power band that begins around the 6,500 rpm mark, I would need to take it to 8,500 rpm and that will fry my bottom end :(

I also have a Polo gearbox with 'GT' ratios which means it has the LOWEST rev drop between gears, but still, can't keep it in the band. With the short gears, if I had a cam that kicked off at 5,000 rpm that would be ok.

[zoidberg]

First, I think you should forget about cams and spend your money on these.

http://www.ebay.co.uk/itm/choose-camshafts-time-them-power-Speedpro-series-New-/260934881376?pt=UK_CarParts_Vehicles_Manuals_Litte rature_ET&hash=item3cc0ee5060


http://www.ebay.co.uk/itm/build-modify-power-tune-cylinder-heads-Speedpro-series-New-/260934880401?pt=UK_CarParts_Vehicles_Manuals_Litte rature_ET&hash=item3cc0ee4c91

Then after you have read them you will know what lift/duration cam will work best with your head mods.
Also this is a good informative read as well.

http://www.ebay.co.uk/itm/220933628518?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
Better to spend a few quid in that direction first, saves alot of heartache later on.

[Leeds_finest]

First, I think you should forget about cams and spend your money on these.

http://www.ebay.co.uk/itm/choose-camshafts-time-them-power-Speedpro-series-New-/260934881376?pt=UK_CarParts_Vehicles_Manuals_Litte rature_ET&hash=item3cc0ee5060


http://www.ebay.co.uk/itm/build-modify-power-tune-cylinder-heads-Speedpro-series-New-/260934880401?pt=UK_CarParts_Vehicles_Manuals_Litte rature_ET&hash=item3cc0ee4c91

Then after you have read them you will know what lift/duration cam will work best with your head mods.
Also this is a good informative read as well.

http://www.ebay.co.uk/itm/220933628518?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
Better to spend a few quid in that direction first, saves alot of heartache later on.

That wouldn't be a bad idea :)

I am really interested in knowing what lift/duration means etc. I would've thought the guy at Kent would've done all of that for me really, but still interesting to know.

...and yes you're right, hearth ache and wallet ache. My engines been set up 3 times now running the wrong cam. It's cost me £84 per time :(

[Leeds_finest]

I'm bidding on cam book and 4 stroke book :)

As for cylinder heads, I strictly sub that out to a professional so i'll rain check on that one :)

[Leeds_finest]

Heads gone in this winter for a harsh skim to raise compression and to have the cam re ground to Kent GS1 spec :)