Tomei 16V poncams + Tomei technical trax 1.5 way LSD

[Alex170984]

I've got cat cams in mine 252/260 8.5/9.0mm lift.

My cr is 10.15 and the cams are terrible for low end torque. I've had to remove my tvis which has improved the situation.

I'm going to build a 11.2 - 11.5 CR engine in the coming months using the oem smallport pistons and a 1.01mm head gasket - I too have Been looking at the Poncams

[Lt86]

(09-13-2016 02:02 PM)Alex170984 Wrote:  I've got cat cams in mine 252/260 8.5/9.0mm lift.

My cr is 10.15 and the cams are terrible for low end torque. I've had to remove my tvis which has improved the situation.

I'm going to build a 11.2 - 11.5 CR engine in the coming months using the oem smallport pistons and a 1.01mm head gasket - I too have Been looking at the Poncams

Good to know!

I track the car from time to time. The most it has seen this year is Nurburgring.
That being said, the majority of it's miles are on the road, really using 2nd and 3rd
gear. So torque is what i'd like most (not very logical in these cars, I know. Haha!)

I'm not looking to damage this so I won't be using the cams you have.
Oldeskewltoy has recommened me to buy 2 exhaust cams from Catcams.
These ones: http://www.catcams.com/products/camshaft...TUP_id=827

Just realised how poor my understanding of what cam and why is so I'm gonna read up a little more.
Thanks for sharing your experience!

[oldeskewltoy]

(09-13-2016 02:02 PM)Alex170984 Wrote:  I've got cat cams in mine 252/260 8.5/9.0mm lift.

My cr is 10.15 and the cams are terrible for low end torque. I've had to remove my tvis which has improved the situation.

I'm going to build a 11.2 - 11.5 CR engine in the coming months using the oem smallport pistons and a 1.01mm head gasket - I too have Been looking at the Poncams

Do you have a dyno print out? Are the cams set correctly? I assume you are using the 260 cam on the intake side? That combo is a bit weak, with 10.15:1, I'd run a a pair of their 244 8.0 cams, or at most a pair of the 252 cams. Running the Poncams isn't likely to improve the performance because the cam timing on the Poncams is longer then the Catcams 260

How did removing the TVIS help? Typically.... removing TVIS doesn't lend itself to improving low end....

[Bean]

Dan, do you know the duration of the poncams @ 0.05"/1mm lift?

[Lt86]

(09-14-2016 06:03 PM)oldeskewltoy Wrote:  How did removing the TVIS help? Typically.... removing TVIS doesn't lend itself to improving low end....

Very curious about this as well, T-vis should improve low-end torque?

[totta Crolla]

(09-15-2016 09:40 AM)Lt86 Wrote:  

(09-14-2016 06:03 PM)oldeskewltoy Wrote:  How did removing the TVIS help? Typically.... removing TVIS doesn't lend itself to improving low end....

Very curious about this as well, T-vis should improve low-end torque?

I would expect the engine appears to run better because allowing more air masks the rich running fueling issue associated with running a standard ecu and bigger camshafts.

[oldeskewltoy]

(09-14-2016 07:36 PM)Bean Wrote:  Dan, do you know the duration of the poncams @ 0.05"/1mm lift?

yep.... you do too... now that you have my "Library"

Btw... this is a handy little tool - https://www.tomeiusa.com/tool/valve_timi...ph-ENG.xls - Helps you understand the timing events....


Additional BTW.... note the cam duration change/difference between 1mm(.040") , and .050"

[Lt86]

(09-15-2016 05:12 PM)oldeskewltoy Wrote:  Btw... this is a handy little tool - https://www.tomeiusa.com/tool/valve_timi...ph-ENG.xls - Helps you understand the timing events....

Very eager to learn here!

So by what you've told me:

stock cam early - 204 degrees @ 1mm make power to 6600
stock cam later - 198 degrees @ 1mm make power to 6500
mild cam - 212-214 degrees @ either 1mm,{.040"} or .050" make power to 7200
mild +1 cam - 220-222 @ either 1mm, or .050" make power to 8000

These are intake cam timings you are talking about?
What about the valve timing center line. How is it decided or what does it do?

[Bean]

Centre line will affect scavenging effect (exhaust gas pulling in intake air due to pulsing of the header design) and also the dynamic compression (when all valves are actually closed). Shifting around the center line can alter the location of the powerband to some degree. That's simplified what modern engines do whit variable cam timing as the air/gases behave differently through the rpm range. In general (very simplified) you would want more overlap (when all valves are open) at high rpms compared to low rpms due to the reduced scavenging effect at low rpms.

People wrote entire books about this so it's hard to explain and there's no one correct answer to every situation as a lot of things have to be accounted for.

[totta Crolla]

(09-16-2016 10:09 AM)Lt86 Wrote:  

(09-15-2016 05:12 PM)oldeskewltoy Wrote:  Btw... this is a handy little tool - https://www.tomeiusa.com/tool/valve_timi...ph-ENG.xls - Helps you understand the timing events....

Very eager to learn here!

So by what you've told me:

stock cam early - 204 degrees @ 1mm make power to 6600
stock cam later - 198 degrees @ 1mm make power to 6500
mild cam - 212-214 degrees @ either 1mm,{.040"} or .050" make power to 7200
mild +1 cam - 220-222 @ either 1mm, or .050" make power to 8000

These are intake cam timings you are talking about?
What about the valve timing center line. How is it decided or what does it do?

Research intake runner length before you make your choice based solely on the above statement.