Tomei Pon Cams S2 Rb25

[Room42]

its closer than that here, just costs $3/L and has to be pumped by hand....

That's worth it.

[boostn0199]

It depends personally if you can justify cams about a 1000 and valve springs another few hundred for gains in midrange and slight top end. To me its worth it but other people would rather spend money somewhere else.

[Ad's]

Im looking for more midrange so it's worth it to me . Plus i have spent too much now to care how much the rest will cost haha.

[SKYMAGGOT]

Anyone have any experience between the poncam 256 8.5 & the Kelford 246-A 262 9.3? For a basic street setup 25 around 350kw with gtx3076. (back to pump gas now as ethanol is getting too expensive @ about $5.50/l & a hassle for mixing).

Doesn't seem to be a lot of results around for the Kelford? 

I don't know a lot about cams with regards to overlap & ramp angles etc but seems like the Kelford is probably better or maybe not much difference?

[R33 GTS25t NZ]

@SKYMAGGOT Iv got Apexi RB25DET VCT Cams not too sure on the duration but they are 8.9mm lift, got to get them refurbd as they are worn on the corners, cant wait! journal bearing GT3582r with apexi power fc, killer time

[SKYMAGGOT]

Ok, have you run them before? Might be better to get new if they're worn which is unusual?

GT3582r usually means roller bearing-I don't think there's a Garrett version that's JB so could be something else? A lot of people in NZ seem to have the TA3410 JB Garrett.

You just running 98?

[GTSBoy]

So many people say they have a GTXXYYr when in reality they have a ChinaBay/offbrand copy.

[Dose Pipe Sutututu]

1 hour ago, GTSBoy said:

So many people say they have a GTXXYYr when in reality they have a ChinaBay/offbrand copy.

Yep.... and when they yield poor results, Garrett turbos then cop a bad reputation.

 

On 23/10/2022 at 11:07 AM, SKYMAGGOT said:

Anyone have any experience between the poncam 256 8.5 & the Kelford 246-A 262 9.3? For a basic street setup 25 around 350kw with gtx3076. (back to pump gas now as ethanol is getting too expensive @ about $5.50/l & a hassle for mixing).

Doesn't seem to be a lot of results around for the Kelford? 

I don't know a lot about cams with regards to overlap & ramp angles etc but seems like the Kelford is probably better or maybe not much difference?

FWIW, I have Kelford 244-B (264/272 9.6mm) and a real Garrett GTX3576R Gen 2 with a 1.01 T3 Garrett divided turbine housing. 0.8bar by 4000rpm, makes 437kW at about 7200rpm, rev limiter at 8600rpm. Boost target was 1.8bar but it bled down to about 1.5bar by the redline (turbo is out of puff).

In some shape or form if you have a real Garrett GTX3076 (hopefully Gen 2?) then our compressor maps are identical.

 

[robbo_rb180]

I have the old 256 poncams ,old gt3076r on factory manifold externally gated. Around 16-17psi on e85 is around 320kw. Very responsive on the street and track. Revs to about 7000rpm. Its more of a 2008-2010 spec era setup only benefit I have is drive by wire. 

These days I'd wouldn't even bother with cams unless going for big power(400+kw).

[Dose Pipe Sutututu]

15 hours ago, robbo_rb180 said:

I have the old 256 poncams ,old gt3076r on factory manifold externally gated. Around 16-17psi on e85 is around 320kw. Very responsive on the street and track. Revs to about 7000rpm. Its more of a 2008-2010 spec era setup only benefit I have is drive by wire. 

These days I'd wouldn't even bother with cams unless going for big power(400+kw).

Patiently waits for that turbo to blow up so you can modernise it haha...

But being a genuine Garrett, I'll be waiting for a while.

[SKYMAGGOT]

16 hours ago, Dose Pipe Sutututu said:

Yep.... and when they yield poor results, Garrett turbos then cop a bad reputation.

 

FWIW, I have Kelford 244-B (264/272 9.6mm) and a real Garrett GTX3576R Gen 2 with a 1.01 T3 Garrett divided turbine housing. 0.8bar by 4000rpm, makes 437kW at about 7200rpm, rev limiter at 8600rpm. Boost target was 1.8bar but it bled down to about 1.5bar by the redline (turbo is out of puff).

In some shape or form if you have a real Garrett GTX3076 (hopefully Gen 2?) then our compressor maps are identical.

 

Every part of your setup is better than mine, I'm doing a new setup on the side but will be early next year sometime before can finish it off, I'm just trying to band aid until then as it feels crap without the E mix

[SKYMAGGOT]

15 hours ago, robbo_rb180 said:

I have the old 256 poncams ,old gt3076r on factory manifold externally gated. Around 16-17psi on e85 is around 320kw. Very responsive on the street and track. Revs to about 7000rpm. Its more of a 2008-2010 spec era setup only benefit I have is drive by wire. 

These days I'd wouldn't even bother with cams unless going for big power(400+kw).

Yeah it's a bit of a band aid until I can sort out a new setup which will be a few months

[SKYMAGGOT]

25 minutes ago, Dose Pipe Sutututu said:

Patiently waits for that turbo to blow up so you can modernise it haha...

But being a genuine Garrett, I'll be waiting for a while.

This is pretty much me, the whole setup is outdated & needs a do over but thought the cams might make it a bit less depressing in the meantime haha

[SKYMAGGOT]

10 hours ago, R33 GTS25t NZ said:

 

Dunno what's up here? lol

[Dose Pipe Sutututu]

9 minutes ago, SKYMAGGOT said:

Every part of your setup is better than mine, I'm doing a new setup on the side but will be early next year sometime before can finish it off, I'm just trying to band aid until then as it feels crap without the E mix

Theoretically a turbo "should" nearly spool the same on either E85 or 98RON, in some regard broscience and brolyticals would say the EGTs are hotter on 98RON thus spool theoretically "should" be better on 98RON.

[SKYMAGGOT]

5 minutes ago, Dose Pipe Sutututu said:

Theoretically a turbo "should" nearly spool the same on either E85 or 98RON, in some regard broscience and brolyticals would say the EGTs are hotter on 98RON thus spool theoretically "should" be better on 98RON.

Yeah it does, just feels a bit flat with less timing, we have 100+ which is 101.5 but the tune is for 98 so could probably pick up a bit with that

[BK]

1 hour ago, Dose Pipe Sutututu said:

Theoretically a turbo "should" nearly spool the same on either E85 or 98RON, in some regard broscience and brolyticals would say the EGTs are hotter on 98RON thus spool theoretically "should" be better on 98RON.

Broscience be incorrect there. E85 has superior spool because of the much increased exhaust gas volume from of how much extra fuel has to be added over 98. The extra 25 - 30% exhaust gas volume on E85 has a far bigger effect on the turbine than the higher egts on 98.

[Dose Pipe Sutututu]

3 minutes ago, BK said:

Broscience be incorrect there. E85 has superior spool because of the much increased exhaust gas volume from of how much extra fuel has to be added over 98. The extra 25 - 30% exhaust gas volume on E85 has a far bigger effect on the turbine than the higher egts on 98.

I suppose you are correct there with the increase volume, however I am wondering how of a difference one would see.

Might have to do a back to back one day on the dyno just for broscience  

[BK]

6 minutes ago, Dose Pipe Sutututu said:

I suppose you are correct there with the increase volume, however I am wondering how of a difference one would see.

Might have to do a back to back one day on the dyno just for broscience  

I notice a MASSIVE difference on the blue 32 with the 6466, like I mean night and day even on part throttle inputs. I have the 98 vs E85 dyno for it on here.

[GTSBoy]

13 minutes ago, BK said:

Broscience be incorrect there. E85 has superior spool because of the much increased exhaust gas volume from of how much extra fuel has to be added over 98. The extra 25 - 30% exhaust gas volume on E85 has a far bigger effect on the turbine than the higher egts on 98.

Pls allow the combustion engineer in the room to correct this.

Ethanol does in fact have a bit more exhaust gas volume than petrol, but it is nowhere near 25-30% extra. The only difference is that ethanol has a higher H:C ratio, so makes more water vapour. For each O2 molecule you use to oxidise a hydrogen, you will create 2x molecules of water. With carbon, each O2 only makes 1 CO2.

While you might use 25-30% more fuel on E85, you use almost exactly the same amount of air to make the same power. Therefore you use almost exactly the same amount of O2, and hence N2 (from the air).

The reality is that the extra water vapour and smaller qty of CO2 really just increases the exhaust gas volume by a few %. Maybe 5. I'm not about to go do the stoichiometry calculations. But, I have recently been doing exactly that for H2 replacement of natural gas in industrial applications and even then, when you're talking about only making water vapour and no CO2, the increase is not as fat as 30%.