Tomei poncams question

[gezed]

does anyone have first hand experience with these? there are Type-A, Type-B and Type-R. 260/252, 260/260, 250/250 respectively. Which one is the best fit for stock turbos? I have heard ppl say that the increased responsiveness is very noticeable though power gains are neglegible anyone can shed a light on this?

[gtrjon]

+1 in for more info. looking into them for my big single build but i wana know more before i dish out the 800-1000 bucks

[GTR-Dad]

Increasing lift and duration reduces airflow resistance so you get a smaller pressure drop. This results in more air entering the engine and less power lost during the exhaust stroke.
I would expect power increases regardless of turbo selection.
Make sure cam timing is set correctly or you'll leave some torque and power on the table.
As cams get wilder you can expect rougher idle and less off boost response. None of the ones you listed should cause problems.

Dan

[Daryl @ RightDrive]

I have the Tomei Type B in my car. With any cams, you are not going to see a big power gain, the cams are designed to increase responsiveness and smooth out the power band. If you are using factory turbos, the Type A are your best bet. Also, if your setup isn't unusually wild, Tomei cams don't usually need adjustable cam gears.

Tomei's cams are some of the biggest (and reasonably priced!) on the market. All research and development was done in house as always with Tomei. They are $780 USD, so don't pay more then that.

Here is what Tomei says about their cams:

Type A - Best suited for factory to N1 turbos, or other smaller aftermarket turbos.
Designed to best suit the stock & N1 turbos for optimum performance balance of low to mid range torque. The Exhaust cams duration was reduced to maintain best idling.

Type B - Best suited for mid to larger sized turbos.
By extending the duration timing compared to the Type A Poncams, both response and peak power was raised and these camshafts best compliment the mid to large size turbo charged applications.

Type R -(for Stock Cat. Equipped Cars)
The Type R camshafts were designed due to popular demand from end users who are looking at upgrading the performance potential of their GTR while staying within the limits of recent street legal requirements. Recent laws on emissions and exhaust noise was made stricter in Japan so to have a quieter car by running smaller exhaust systems raises the exhaust back pressure which greatly reduces the response and hinder performance. Our engineers then designed these Type R camshafts to suit the needs of those who need to keep such setup and benefit with performance gains.

Hope that helps guys!

[gezed]

thanks a lot for the info guys.

i guess my best bet is the Type A, im more focused on improving responsiveness so i will probably look into lightweight flywheel as well. In terms of engine response, those 2 upgrades would make a noticeable improvement to response right? is there any other upgrades that arent ridiculously expensive that would help with response?

Dan, arent these cams just a drop in replacement of the oem? i read that nothing needs to be adjusted for the install

[evilgtr]

gezed - the type b poncams are the direct drop in cam with no addictional valve train modifications needed. The pro cams from tomei are the series offered by tomie that require the user to upgrade head components because of the larger lift. Dary had a very accurate description in regards to what cams are used for what turbos. I am personally running the tomei poncams type B, I have the 264 duration 9.15mm lift and I love them ! I am also running N1 turbos ( I think )

And yes the responsiveness will be very noticable provided you set them up with the proper timing - strongly reccommend adj cam gears for what they are worth. As Dan mentioned earlier as well Cam timing is very important but a session on the dyno and a competant tuner will be able to set this up to your liking whether your looking for mid range or high end peak power.

Engine response mods - my 2 favorite mods that increased my responsiveness were a lightweight flywheel clutch set up - Fidanza makes a excellent light weight flywheel for the RB26 that is completly rebuildable and priced very fair might be the best bang for your buck if you are on a budget.
The other thing you must get done and will cost you $120 is have a divertor pipe welded into your twin turbo charge pipe ! there is a gtrc member that does this I cant remeber his name but hes out east and hes the one who did mine. I honestly coundt believe the difference it made on my car !

hope this helps

[NismoS-tune]

you're running N1 turbos? how you making so much power lol

As for the stock twin turbo pipe being modded, it helps but it's the least benefical of the split pipes available. The cost is why most GTRCers get it. The next step is Greddy or HKS which are almost 3 times the prices.

gezed - the type b poncams are the direct drop in cam with no addictional valve train modifications needed. The pro cams from tomei are the series offered by tomie that require the user to upgrade head components because of the larger lift. Dary had a very accurate description in regards to what cams are used for what turbos. I am personally running the tomei poncams type B, I have the 264 duration 9.15mm lift and I love them ! I am also running N1 turbos ( I think )

And yes the responsiveness will be very noticable provided you set them up with the proper timing - strongly reccommend adj cam gears for what they are worth. As Dan mentioned earlier as well Cam timing is very important but a session on the dyno and a competant tuner will be able to set this up to your liking whether your looking for mid range or high end peak power.

Engine response mods - my 2 favorite mods that increased my responsiveness were a lightweight flywheel clutch set up - Fidanza makes a excellent light weight flywheel for the RB26 that is completly rebuildable and priced very fair might be the best bang for your buck if you are on a budget.
The other thing you must get done and will cost you $120 is have a divertor pipe welded into your twin turbo charge pipe ! there is a gtrc member that does this I cant remeber his name but hes out east and hes the one who did mine. I honestly coundt believe the difference it made on my car !

hope this helps

[evilgtr]

I think I'm running N1's we aren't sure haha I know they came off a formula D R34 Gtr that was in the ball park of 600whp, il know for sure if I end up pulling them off and going with a single. The modified twin turbo pipe is a excellent mod and the comparable alternatives you mentioned are upwards of 10 x the price. The tt pipe mod $100 a greddy suction kit is over $1000 after shipping. I honestly cant believe the difference it made on my car I think everyone should do it! If it wasn't winter I would take mine off and mail it to you to try lol it's a 10 minute job to pull it off.

[Bugsly17]

I have tomei type b poncams for sale btw......

[NismoS-tune]

I think I'm running N1's we aren't sure haha I know they came off a formula D R34 Gtr that was in the ball park of 600whp, il know for sure if I end up pulling them off and going with a single. The modified twin turbo pipe is a excellent mod and the comparable alternatives you mentioned are upwards of 10 x the price. The tt pipe mod $100 a greddy suction kit is over $1000 after shipping. I honestly cant believe the difference it made on my car I think everyone should do it! If it wasn't winter I would take mine off and mail it to you to try lol it's a 10 minute job to pull it off.

No need to send it to me, I run HKS twin turbo pipes, Racing chamber.

[allwheeldrifter]

The other thing you must get done and will cost you $120 is have a divertor pipe welded into your twin turbo charge pipe ! there is a gtrc member that does this I cant remeber his name but hes out east and hes the one who did mine. I honestly coundt believe the difference it made on my car !

hope this helps

my car was dyno tuned at 333 rwhp, i did the twin turbo divided pipe and installed z32 mafs, went back to the dyno, and gained between 10 to 15 rwhp. its acceptible, but i didnt notice ANY increase in response, if anything, i noticed more lag(z32 mafs?). kinda disapointing...

[evilgtr]

So you gained 10-15whp but you feel you lost response ? All this after a tune ? That could be %100 related to your tune and how your tuner dialed your car in. What turbos are you running and how much boost ?

Some after market turbos are prone to "shuffling" on the RB26 so it may make more of improvement on some setups and not so much on others depending on your turbo situation. Unfortunatly I didn't tune my car before and after the install but I did definatly noticed the increase in hp and torque

[allwheeldrifter]

So you gained 10-15whp but you feel you lost response ? All this after a tune ? That could be %100 related to your tune and how your tuner dialed your car in. What turbos are you running and how much boost ?

Some after market turbos are prone to "shuffling" on the RB26 so it may make more of improvement on some setups and not so much on others depending on your turbo situation. Unfortunatly I didn't tune my car before and after the install but I did definatly noticed the increase in hp and torque

oem turbos.............. but i have a set of -5s ready for next summer

[evilgtr]

Once the -5's are installed you will appreciate having the divided charge pipe, try a seach of "added -5's now I have turbo shuffle" at higher boost levels this will really benfit you.

[allwheeldrifter]

your probably right