R/R graph

[Gaz D 6]

Is it me being daft or is the torque a little low?

[dcc 855]

My favourite part of this thread is all the supporting information to help me decide what the f*** you're on about

[Tom Fenton 1,541]

Without spec of the engine who can say?

[Gaz D 6]

11 hours ago, dcc said:

My favourite part of this thread is all the supporting information to help me decide what the f*** you're on about

Alright lad calm down. I’m obviously not the sharpest when it comes down to these things or I wouldn’t be asking the question, a simple “we need the engine specs” would of been the the polite way but it looks like your arrogance got in the way

[Gaz D 6]

11 hours ago, Tom Fenton said:

Without spec of the engine who can say?

Sorry Tom my bad. IT’s gti6 engine with cat cam 106’s, jenvey 45s with satchell inlet . 

[petert 586]

Hey bloke, the reality is you’re trying to fudge flywheel figures derived from the wheels, with losses from tyres and gearbox. Rubbery figures at best. Take them with a grain of salt. If it goes better after than it did when driven in, you’re on a winner. Unless you have multiple runs from the same session, with data verifying the changes made between runs, the figures are somewhat meaningless. 

[Porter87 18]

Here's mine for comparison, on the same rollers 

 

My spec is 

 

XU10J4RS engine (gti6) 

 

Newman phase 2 cams with some head work

Jenvey throttle bodies (330cc injectors)

Jenvey inlet manifold

Pug racing exhaust manifold

Forged rods

Forged high comp pistons 

 

but like Peter said, if it drives better dont worry about the figures as they are meaningless 

 

Edited December 5, 2022 by Porter87

[Porter87 18]

I plotted the figures in excel to show the wheel HP/torque from the actual readings. 

 

[dcc 855]

On 12/4/2022 at 7:46 AM, Gaz D said:

Alright lad calm down. I’m obviously not the sharpest when it comes down to these things or I wouldn’t be asking the question, a simple “we need the engine specs” would of been the the polite way but it looks like your arrogance got in the way

Hardly arrogance is it... either way your cam timing looks no where near right, I bet that feels flat under 5k, which is probably why you're here asking the question. Compare it to porters graph.

 

Are you on standard pistons? What about exhaust? Have you checked valve seats? 

 

If you're on standard pistons you're probably close to the valves kissing the piston, or to avoid contact they're massively retarded, particularly so if the heads ever been off for a skim. Timing up cams properly isn't the easiest thing to do, but it's worth its weight in gold to get right

 

For comparison a friend made more power with less cam, and has a far healthier spread of torque and power delivery. Same inlet manifold, bodies, gti6 exhaust manifold. 

 

 

[Gaz D 6]

On 12/4/2022 at 11:35 AM, petert said:

Hey bloke, the reality is you’re trying to fudge flywheel figures derived from the wheels, with losses from tyres and gearbox. Rubbery figures at best. Take them with a grain of salt. If it goes better after than it did when driven in, you’re on a winner. Unless you have multiple runs from the same session, with data verifying the changes made between runs, the figures are somewhat meaningless. 

Completely understand your point thanks Peter. It now seems to go mental at around 5.5k revs compared to 4k. I think it’s just going to take a bit of getting used to it as it’s obviously quite different now the cams and ITB’s have been fitted

[Gaz D 6]

10 hours ago, Porter87 said:

Here's mine for comparison, on the same rollers 

 

My spec is 

 

XU10J4RS engine (gti6) 

 

Newman phase 2 cams with some head work

Jenvey throttle bodies (330cc injectors)

Jenvey inlet manifold

Pug racing exhaust manifold

Forged rods

Forged high comp pistons 

 

but like Peter said, if it drives better dont worry about the figures as they are meaningless 

 

That’s a brilliant comparison thanks mate. Your torque seems to peak a bit before mine which I’d prefer because as much as I enjoy thrashing it, I don’t like to do it :-) I just think I’ve got to get used to the changes I’ve made pal

[Gaz D 6]

3 hours ago, dcc said:

Hardly arrogance is it... either way your cam timing looks no where near right, I bet that feels flat under 5k, which is probably why you're here asking the question. Compare it to porters graph.

 

Are you on standard pistons? What about exhaust? Have you checked valve seats? 

 

If you're on standard pistons you're probably close to the valves kissing the piston, or to avoid contact they're massively retarded, particularly so if the heads ever been off for a skim. Timing up cams properly isn't the easiest thing to do, but it's worth its weight in gold to get right

 

For comparison a friend made more power with less cam, and has a far healthier spread of torque and power delivery. Same inlet manifold, bodies, gti6 exhaust manifold. 

 

 

Sorry DCC. I’ll hold my hands up and admit I was probably a bit over sensitive there ! The mapper told me he thought my timing was retarded but it was late in the day and didn’t have time to delve any deeper. I must admit the cams were fitted to the existing timing marks and only checked valve to piston clearance by feeling for any clash turning it over by hand! (I know this was a bit dangerous and stupid) is it possible to to degree the timing with there engine fitted? I presume even if it was it’d be bloody tight ! 
you are right when you say it’s a bit flat before  5k. It’s running standard pistons and rods and standard 6 manifold. Thanks for the input mate

[dcc 855]

You need to sack the mapper and get somebody who's worth their money! 

 

You're in a difficult position tbh, if the engine was standard, head never been off, I think you *just* have enough room for those cams, possibly pushing your luck a little. First port of call for me in your situation would be to set piston to tdc and disconnect a spring retainer on the inlet, let it drop down to the piston and then measure how much it comes back up by until it seats. It's not going to be easy with the head on, but it's doable.

 

I honestly can't remember what clearance you need off the top of my head but I'm sure @welshpugwill be along soon and he's probably got a note somewhere with the figure, or Peter t (I want to guess you need 3.5mm, in my head 1.5mm + 1.95mm rings a bell)

 

Its sadly not just a case of timing the cams up on a standard engine. depending on the budget I'd be tempted to take head off and get the pistons out for a bit of clearance work for peace of mind. It's something that can be done by Allan Storer at bridge craft engineering 

[Gaz D 6]

22 minutes ago, dcc said:

You need to sack the mapper and get somebody who's worth their money! 

 

You're in a difficult position tbh, if the engine was standard, head never been off, I think you *just* have enough room for those cams, possibly pushing your luck a little. First port of call for me in your situation would be to set piston to tdc and disconnect a spring retainer on the inlet, let it drop down to the piston and then measure how much it comes back up by until it seats. It's not going to be easy with the head on, but it's doable.

 

I honestly can't remember what clearance you need off the top of my head but I'm sure @welshpugwill be along soon and he's probably got a note somewhere with the figure, or Peter t (I want to guess you need 3.5mm, in my head 1.5mm + 1.95mm rings a bell)

 

Its sadly not just a case of timing the cams up on a standard engine. depending on the budget I'd be tempted to take head off and get the pistons out for a bit of clearance work for peace of mind. It's something that can be done by Allan Storer at bridge craft engineering 

The mapper was spot on and honest. He said he would look at the timing but with me telling him I didn’t know valve clearance he said he’d need  to do more work than he had time for late on a Friday tea time. I’m obviously no expert but what you are saying makes sense and I think I’ll try and talk my mate into measuring the clearance for me to see if i have scope to adjust the timing. Will it need remapping if the timing is adjusted? Thanks again for the advice mate 

[dcc 855]

I'm not very clued on with mapping but I would say it will need looking at. 

[petert 586]

The recommended LCL for Catcams 106 inlet is 108º, which I'd agree with. If you've installed the cams on the oem positions, you're probably at 112-114º, which is definitely less than ideal. You're giving away heaps of torque and not getting any more top end. With standard pistons you couldn't install the inlet at 108º (1.75mm lift @TDC) without risk of bending valves anyway.

 

One way to optimise your build would have been to cut the inlet pockets slightly deeper and skim the block to regain the lost CR.

[petert 586]

Here's an earlier one of mine. The RPM cut was 8200, not 7700, thus about 500rpm out. Power is kW at the wheels.

BYP Dyno 9 Jan.pdf

Edited December 8, 2022 by petert

[Gaz D 6]

10 hours ago, petert said:

The recommended LCL for Catcams 106 inlet is 108º, which I'd agree with. If you've installed the cams on the oem positions, you're probably at 112-114º, which is definitely less than ideal. You're giving away heaps of torque and not getting any more top end. With standard pistons you couldn't install the inlet at 108º (1.75mm lift @TDC) without risk of bending valves anyway.

 

One way to optimise your build would have been to cut the inlet pockets slightly deeper and skim the block to regain the lost CR.

Thanks for your help Peter . Am I right in thinking then that I’m running roughly 4-6 degrees retarded?

I was told that these cams were designed to maximum lift without having to pocket the pistons. (As long as the head hadn’t been skimmed). What is the minimum clearance needed and what clearance would we have if the cams were set at 108 degrees at TDC? I know gasket thickness would play apart and as we are talking very small figures I understand that you may be able to give an accurate answer.

thanks again. 
 

[Gaz D 6]

9 hours ago, Gaz D said:

Thanks for your help Peter . Am I right in thinking then that I’m running roughly 4-6 degrees retarded?

I was told that these cams were designed to maximum lift without having to pocket the pistons. (As long as the head hadn’t been skimmed). What is the minimum clearance needed and what clearance would we have if the cams were set at 108 degrees at TDC? I know gasket thickness would play apart and as we are talking very small figures I understand that you may not be able to give an accurate answer.

thanks again. 
 

My

[petert 586]

My safe limit for a std RS engine is 0.055” lift at TDC. What I consider safe and what others think might be two different things. 1.75mm is approx 0.068”. Just 13 thou more? 

 

You could take the risk and set it up at that. It may run forever. Either way you’ll have to take the head off to fix it eventually.

 

The choice is yours.

[Spesh 31 1 Cars]

Image (4) by Mark Needs, on Flickr

 

 

Thats mine.

 

Totally stock engine, Jenvey 48's on a satchell inlet, Speeduino ECU.   Rebuilt head with new guides etc but a rather tired bottom end.

Edited December 10, 2022 by Spesh

[Gaz D 6]

2 hours ago, Spesh said:

Image (4) by Mark Needs, on Flickr

 

 

Thats mine.

 

Totally stock engine, Jenvey 48's on a satchell inlet, Speeduino ECU.   Rebuilt head with new guides etc but a rather tired bottom end.

 

On 12/9/2022 at 8:04 AM, petert said:

My safe limit for a std RS engine is 0.055” lift at TDC. What I consider safe and what others think might be two different things. 1.75mm is approx 0.068”. Just 13 thou more? 

 

You could take the risk and set it up at that. It may run forever. Either way you’ll have to take the head off to fix it eventually.

 

The choice is yours.

I think in the new year I’ll have the timing set to give me that sort of clearance or possibly have the pistons pocketed as it cost a lot to get where I am so a bit more is what it is! Thank again Peter 

[Gaz D 6]

2 hours ago, Spesh said:

Image (4) by Mark Needs, on Flickr

 

 

Thats mine.

 

Totally stock engine, Jenvey 48's on a satchell inlet, Speeduino ECU.   Rebuilt head with new guides etc but a rather tired bottom end.

Very nice smooth curves there mate