Upgrade Cams... 270's? Fast road? Calling the guru's

[Victor Meldrew]

Dan will be putting in a set of "fast road" cams when he fixes the broken bits.. I am sure he said they were 270's.

Would you expect the std ECU to be ok with these.

Its a mk1 135 so it has a ported head, 160 style inlet plenum, 58mm throttle body, Janspeed exhaust manifold and 2bular exhaust.

The last dyno run gave 150bhp but that was with the old Janspeed exhaust and a crap Ebay filter set up.

New exhaust, new cams, better filter... too much to hope for 160 bhp?

[fd]

Dan will be putting in a set of "fast road" cams when he fixes the broken bits.. I am sure he said they were 270's.

Would you expect the std ECU to be ok with these.

Its a mk1 135 so it has a ported head, 160 style inlet plenum, 58mm throttle body, Janspeed exhaust manifold and 2bular exhaust.

The last dyno run gave 150bhp but that was with the old Janspeed exhaust and a crap Ebay filter set up.

New exhaust, new cams, better filter... too much to hope for 160 bhp?

I put a set of Piper 270's on my stock S1 years ago . . . I wouldn't do it again . . . far too much buck for nothing like enough bang, it ran just fine on the MEMS.

I'd be quite susprised it you get anything like 160 out of it . . .

Fd

[ironside]

Doesn't the 135 already have fancy cams?

Mine made 150bhp with 270 cams in it (ported, bigger valves but plastic plenum & 48mm TB)

[Victor Meldrew]

Doesn't the 135 already have fancy cams?

Mine made 150bhp with 270 cams in it (ported, bigger valves but plastic plenum & 48mm TB)

Fancy head.. std cams..

[robin]

I had a similar setup to yours a long time ago - 135 head, alloy plenum, sports exhaust, no cat, ITG intake; only difference was standard TB and exhaust manifold.

I then fitted the slightly milder piper cam (266 or something it was called at the time) and got very nearly 160 on the MEMS. Fitted an emerald and Dave Walker couldn't get any additional peak power out of it, though he did smooth it out some and regained something in the midrange. In the end I ran on the MEMS most of the time, because it started & idled better and was better behaved in traffic. I used the emerald on the track with the increased rev limiter

The standard exhaust manifold is a restriction whenever you increase overlap significantly, so the fact that you have the Janspeed one will help (a bit). I think it will allow you to hold torque up a bit further in the rev range, and so more power might be available to you at >7000 RPM (i.e. only if you fit an emerald-type solution).

If you don't get verniers it's hit and miss as to whether it will run at all well.

Expect the increased overlap and duration to cost you something at the low end (<3,000). This is because the cylinder filling will actually be worse at this point in the rev range. The extra duration allows more air to be expelled at the start of the compression stroke, where the intake valve is still open; also the extra overlap increases the amount of exhaust gas sucked back into the cylinder during the start of the intake stroke.

Any gain you get from the cams won't cut in until ~4,000. At that point the extra duration and lift compensate for the standard engine's inability to breathe and you get increased chamber filling all the way to the red line. If you have the narrower bore janspeed manifold you may also see some gains from the overlap. It all depends on maintaining gas speed in the primaries - the momentum of the cooling and shrinking gas vanishing down the pipe causes a small vacuum behind it - with proper timing of the exhaust valve, the valve shuts just at the time when that vacuum is at its peak, and so you start the intake stroke with (a) a clean cylinder and (b) the exhaust vacuum is used to kick start the flow of air from the intake manifold. For this to work well, your exhaust manifold has to be matched to the gas flow.

However, the real limitation of the whole thing is the weedy intake valve size, and given free choice and time, I think you will always get a better result spending your money on bigger valves and associated head work than on bigger cams. Bigger valves win across the range; bigger cams lose at the bottom and win at the top.

Cheers,
Robin

[cla5h]

That's just what I was going to say!

[Victor Meldrew]

Kind of half way with the 135 head on the porting.

I didnt think is was worth changing the head because it wouldnt be a 135 anymore.... might sound strange. NEXT HGF the valves will be getting made bigger, dont see the point in pulling the head off it till I need too. The cams are only getting done because he has a set sitting there and the belts etc is coming off anyway after it threw the crank pulley.

Like the idea of upping the revs a bit. Say I go up 500rpm, is there uprated rod bolts/valve springs/followers etc that I would need or would the stock engine bits be good enough....

(comparing reliabilty to a Honda )

[Victor Meldrew]

I was considering a 2bular exhaust manifold after seeing the superb quality of the ehaust he made for me. The janspeed maniflold is starting to look a bit grotty so it wont be too long before I find another hole I think.

I would imagine Jim would know how to spec the exhaust to match the engine/cam set up. I was also thinking about ceramic coating for the manifold. I have read somewhere that it increases power as well by changing the cooling down characteristics of the exhaust gasses.. kind of ties in with the above about velocity I think.

One of the guru's manage to explain it to me in laymans terms?

[Andy G]

Go on John - see if someone can manage to get an Elise to idle more roughly than mine

not allowed the 58mm TB, but mine was 165 at Dave Andrews - will stall below 2000rpm when you move off though........so it does indeed need the rough stuff even if it might not like it

[Victor Meldrew]

Go on John - see if someone can manage to get an Elise to idle more roughly than mine

not allowed the 58mm TB, but mine was 165 at Dave Andrews - will stall below 2000rpm when you move off though........so it does indeed need the rough stuff even if it might not like it

Thought Noops's 160 already did that. Think he's fixed it now though.

[Andy G]

Thought Noops's 160 already did that. Think he's fixed it now though.

His idles like my e-class in comparison to the RLC

[Victor Meldrew]

Thought Noops's 160 already did that. Think he's fixed it now though.

His idles like my e-class in comparison to the RLC

You only idle when your going slow.......


who wants to go slow anyway.

[GregR]

John, do I sense you've got too much money just now??

[Victor Meldrew]

John, do I sense you've got too much money just now??

No.. just a broke engine that needs money spent on it to get it going againg.... if your spending lots anyway, it may as well be LOTS...

[hiscot]

tend to agree with robin if the heads off fit the larger valves , sorry i didnt as its a lot more hassle than upgrading the cams once its rebolted together , and kinder on the mems ecu
std comp is 10.5:1 most forged pistons use higher 12.0:1 and thats where the extra torque is from , so if you have had your head skimed you will get a torque increase i have a heavy skimed head but also have fantastic torque on a std larger s2 6 stud manifold ( the 4 stud is the first restriction for any upgrades imo )
if you havent already get the prt fitted well worth it for stable running temps