Piper 300 Cam Whats It Like ?

[christopher 5 1 Cars]

I'm intrested to see who is running a 300 degrees piper cam with a decent CR 11+ and carbs or throttle bodies.

 

How is the power band? And how does it behave below 3000rpm.

 

Thanks

Edited September 29, 2006 by christopher

[Bam 0]

>I'm intrested to see who is running a 300 degrees piper cam with a decent CR 11+ and carbs or throttle >bodies.

witch engine?

do you have more details (cam)?

 

>How is the power band?

very late... >5000+

 

>And how does it behave below 3000rpm.

you loose lot of torque...

 

cheers

[smckeown 1]

Surely the answer completely depends on the exact compression. 11:1 would be a different answer to 12:1

[christopher 5 1 Cars]

witch engine?

do you have more details (cam)?

 

 

Surely the answer completely depends on the exact compression. 11:1 would be a different answer to 12:1

 

This is the spec of the cam that I am considering. I asked here because some of you guys are running 300o

piper cams on your GTi's so it might give me at least an idea, I don't think anyone is here on a TU but I may be wrong. SO trying to get an idea of how a cams with this kinda duration will behave on a high CR engine

 

 

This is the cam specifications. Values are lifted stright from their site so not sure about the clearance

 

Cam: Piper P13BP300

Range: 3000-7500

Duration. 300 deg 300 deg

Timing: 45 - 75/75 - 45

Valve lift: .400" 10.16mm / 400" 10.16mm

Full Lift Inl ATDC Exh BTDC 105 deg

Valve clearance .010" / .25mm

 

It will be a TU application.

Race 1294cc TU24 head

Twin 40's with 34 or 36mm chokes

TU5J4 1,6 block

CR will be in the high 11's 11.9 maybe not totally sure yet I can lower a bit if required

Edited September 29, 2006 by christopher

[PumaRacing 2]

This is the spec of the cam that I am considering. I asked here because some of you guys are running 300o

piper cams on your GTi's

 

So what? The XU BP300 isn't necessarily going to be anything like the TU BP300 and even if it were the engines are completely different so there's no comparison. You need to move this to the TU forum.

[veloce200 3]

So what? The XU BP300 isn't necessarily going to be anything like the TU BP300 and even if it were the engines are completely different so there's no comparison. You need to move this to the TU forum.

 

yes 300 cam in a TU will likely be a lot more peaky than in an XU.

[christopher 5 1 Cars]

Well ok ok don't shoot me down at once now I only asked..

 

Just trying to get an idea how it will drive...

 

Who is driving a 1,6 Gti with a 300o piper cam and carbs or throttle bodies then....

[PumaRacing 2]

Just trying to get an idea how it will drive...

 

Well you aren't going to by asking about a completely different engine so why even pursue it?

[stu_woac 1]

thats abit of a low valve lift, but I suppose you want clearance I mean mines a 11.6mm lift

[christopher 5 1 Cars]

thats abit of a low valve lift, but I suppose you want clearance I mean mines a 11.6mm lift

 

 

Thats what I thought. But it seems impossible to compare the different manufacturers. Is it low becuse they use a different clearance in their catalog? To for example catcams..

 

At the top it says "Valve lifts quoted assume a rocker ratio of 1.4:1 - Rocker ratio varies with base circle size. Therefore competition cams may produce more lift than quoted"

[Sandy 191]

If the headwork is working, you won't need that much duration with those valve sizes.

[christopher 5 1 Cars]

If the headwork is working, you won't need that much duration with those valve sizes.

 

The headwork is something I am really counting on Sandy

[Sandy 191]

Is it special?

[Guest Nuno205Rallye]

IMHO replacing a TU24 Alloy block for a Tu5 iron block in a 20CM22 205 Rallye is just plain criminal

 

 

 

The cars are allready rare, it's the future Dodo of the 205 Range

[christopher 5 1 Cars]

Is it special?

 

I'm hoping so Sandy. I'm having full race spec on the head and inlet manifold together by Guy Croft. The guy rebuilds and betters cosworth and arbarth engines on a daily basis and his last 1.6 XU gave over 170bhp

 

 

IMHO replacing a TU24 Alloy block for a Tu5 iron block in a 20CM22 205 Rallye is just plain criminal

The cars are allready rare, it's the future Dodo of the 205 Range

 

Everyone is entitled to their opinion Numo

I'm a stickler for originality myself. Thats why I would never just stick a 106 Gti engine in or something like that. The car would loose its "205 rallyness". It remains to see whether using a longer stroke block with flat pistons will remove the soul of the TU24. But it will also increase the CR to race spec without having the resort to high compression pistons that probably disturb the flame front progression. I'm confident it will be a match made in heaven anyway. And if not then I'll put a TU24 block back in with mahle pistons, that I will be building anyway. I have a few in the workshop still

 

This is the spec that I am planning:

TU24 head and inlet manifold modfied to race spec by Guy Croft

rally camshaft (TBD) with new followers and uprated springs

Twin 40 weber DCOM webers with 34 or 36mm chokes

CSC marmiite 421 exhaust manifold.

Supersprint intermediate and backbox

ignition TBD Standard TU24 curve or mapped ignition

TU5J4 block

Lightened TU5 flywheel with standard clutch or TU3/24 with uprated clutch

ITG air filter

Standard TU24 gearbox

Edited October 2, 2006 by christopher

[Sandy 191]

Christopher, I was suggesting a 300 degree cam would possibly be too much for the TU24, I didn't realise you were builing a TU5, you will need more duration for a TU5.

[Guest Nuno205Rallye]

Well...

 

 

Flame front progression using high dome pistons in a TU24 is nothing to worry about for 2 reasons, the dome is never too big to achieve about 11,5:1 with a standart head, and the rod ratio of this engine.

 

 

The piston in the TU24 is never long enough in the TDC and BDC to cause any problems with flame front the problem lies in the side thrust in the piston skirts and the loads imparted on the rods

 

It's a great litle engine though, never seen a reason to change it to a heavy TU5 block, that needs much fettling to achieve high compression with a TU24 head

 

And the Rallyness of the 205 Rallye comes mainly from it's engine capacity, it is a special homologation version of a 205 GTI that was made to be competitive in Rallyes in the up to 1.3 liter Class.

 

The weak link in your configuration is the MA Gearbox as used in the 205 Rallye, very bad version. the 106 Rallye one is better (stronger) and also has the 13X59 final gear, next in line is a 106 GTI gearbox with a 14X60 final gear from the 205 Rallye or a 13X59 or even a 14X64