183 replies to this topic

[Thorney]

Just catching up on this thread - great stuff. You may be interested to know that we use the Piper cams in conjuction with the TB based stage 4 and on the stage 3 NA tunes we've done.

[clipping_point]

Just catching up on this thread - great stuff.

You may be interested to know that we use the Piper cams in conjuction with the TB based stage 4 and on the stage 3 NA tunes we've done.

Do you have a RR dyno?

[speedster]

Update for wiring of 68mm TB.

Basically there are 8 pins, pin 1 + 2 are for the motor, then there are 2 potentiometers - pins 3 + 6 with 8 as the wiper
and pins 4 + 7 with 5 as the wiper.

8 7 6 5
1 2 3 4
pin configuration used, viewed with plug clip at top

As the 68mm TB opens the opposite way to the standard TB, the wires to pins 3 + 6 and pins 4 + 7 need swapping around.
So that wire 3 goes to pin 6 and wire 6 goes to pin 3, then wire 4 goes to pin 7 and wire 7 goes to pin 4.

This changes the potentiometer output to the same as the original.

I will update with cable colours once the TB is fitted.

vocky, do you know how the TB feeds back throttle position to the ECU. I assume its one of the potentiometers, but which one

[vocky]

Vocky, do you know how the TB feeds back throttle position to the ECU. I assume its one of the potentiometers, but which one

sorry for the extremely long wait for a reply

It appears both potentiometers feed a signal back to the ecu, one signal raises the resistance the other lowers it

[speedster]

sorry for the extremely long wait for a reply

It appears both potentiometers feed a signal back to the ecu, one signal raises the resistance the other lowers it

got it figured.
Now I need a recommendation for a set of cams that will work with a race ported head. JBP are offering me the following kit but should i stick with stage one cams if I have a Dbilas intake and Full Milltek exhaust (plus maybe the 68mm TB) attached?

- Stainless Steel 1mm+ Intake, Stock sized Exhaust valves
- GM ECOTEC Adjustable Timing Gears
- JBP ECOTEC Stage 1 Camshafts
- JBP/WISECO Forged Aluminum Pistons, Locks, Pins and Rings
- Fully Race Ported Head
- 5 Angle Valve Job
- Bronze Valve Guides
- HD Valve Springs
- HD Retainers
- Chromemolly Steel Locks

Thorney, could you offer a similiar kit? Is so what's your price

[clipping_point]

What does this silly Stage 1 business mean? It is lift and duration that is interesting!! Myself i will have: - Race ported head with 11,5:1 CR + 3-angle-job - Double valve springs - Ti retainers - Adj cam gears - Piper 267° regrind According to all sources the +1 mm valves are a useless investment.

[speedster]

What does this silly Stage 1 business mean? It is lift and duration that is interesting!!

Myself i will have:
- Race ported head with 11,5:1 CR + 3-angle-job
- Double valve springs
- Ti retainers
- Adj cam gears
- Piper 267° regrind

According to all sources the +1 mm valves are a useless investment.

OK But whats the science behind cam selection?

[clipping_point]

Dunno really.... I guess you can simulate the whole combustion process. I got software to do it but haven´t done it yet (a lot of geometry data has to be inserted). Instead I chose the 267° cam to give me 10-15 extra HP, and a reasonable idle. By enhancing the flow I get even more top power.

[clipping_point]

And unless you increase the flow (thru a hi-duration cam), you do not need the p&p. With a a hi-duration cam you need higher CR. But it seems you get a different answer for every guy you ask. Some say my 267 is way too racy, and other would not consider installing a cam that mild!

Edited by clipping_point, 19 December 2005 - 03:58 PM.

[clipping_point]

Some guys have had problems with the Piper cams and high revs. I´m thinking that by using double springs, and Ti retainers, the cam followers will work to +8000 rpm with no problem.

[vocky]

the piper '270' degree cams are probably the best option and only £235 the pair inc vat they give a good performance boost with a big valve head and I recommend them personally I would say don't bother with adjustable cam sprockets modern cam grinding machines are very accurate Regarding the valve sizes, I suppose with a standard sized 'race valve' vrs a +1mm 'race valve' the gains are not much, but a standard valve is pretty poor in comparison

[clipping_point]

personally I would say don't bother with adjustable cam sprockets 

modern cam grinding machines are very accurate 

Dude and I bought adjustable cam gears from carcustom at $235.

As I see it (from what I´ve heard):

• Some gains can be accomplished from using a different "lobe separation" other than standard
• to match the harmonic pulses in the inlet and outlet the cam timing is crucial

You are building a new machine, so all ways to make adjustments are good. But you got to know your business to set it up propely (and I don´t)

Edited by clipping_point, 19 December 2005 - 04:37 PM.

[vocky]

But you got to know your business to set it up propely (and I don´t)

that's the main reason many don't get any gains (infact they loose power )

set up correctly and a couple of hp is possible

it's just the '£' vrs 'hp' 'is it worth it' syndrome

[speedster]

I asked JBP for bigger valves and this is what they replied with:

No problem. However, there is a ratio between the exhaust and intake valve
that has to be matched. A 1mm+ size is the largest we can go, otherwise a
full run of custom valves would have to be manufacturered: and would be very
expensive.

Edited by speedster, 19 December 2005 - 07:28 PM.

[Thorney]

Some guys have had problems with the Piper cams and high revs.

I´m thinking that by using double springs, and Ti retainers, the cam followers will work to +8000 rpm with no problem.

Agreed

Hi revs and Piper cams don't work too well, you need more than just cams to get a decent gain with longevity.

[clipping_point]

I asked JBP for bigger valves and this is what they replied with:

No problem. However, there is a ratio between the exhaust and intake valve
that has to be matched. A 1mm+ size is the largest we can go, otherwise a
full run of custom valves would have to be manufacturered: and would be very
expensive.

The size of the standard valves is not the issue. Instead the ports are too small.

My ported head retain the standard valves, the same goes for Dudes 230-240 HP monster.

[speedster]

JBP can grind the cams to the Piper specs too.

[clipping_point]

JBP can grind the cams to the Piper specs too.

Can it be any cheaper? Cost?

But of course, a new grind would be nicer than a regrind i guess?

[speedster]

JBP can grind the cams to the Piper specs too.

Can it be any cheaper? Cost?

But of course, a new grind would be nicer than a regrind i guess?

Purchasing the cams as part of the JBP Race head kit, no extra charge for specifying the cam specs. Grind is from blanks.

[clipping_point]

These are my regrinds