38 replies to this topic

[bladerunner]

As per title I'm wondering the sort of power to expect on a stage 2 supercharged car running standard exhaust with the pre-cat removed. The reason I ask is the only real option to upgrade the exhaust properly is to go for a tullet but the price for the whole system is eye watering - is it really worth it for stage 2 on a budget ?

[smiley]

It also depends on your rpm cutoff, but i would say 240isch.

[Wolfstone]

I think Stage 2 SC boys normally change the NA back box for a turbo one to gain most benefit.

[Andrew aka Stuwy]

240/250

 

the same as an "uprated" exhaust.

 

Makes next to no difference if any at all

[smiley]

You can measure the pressure in your system.

Asuming you will use obdtuner, you can put in a tmap sensor.

With a cheap bluetooth obd dongle you can readout the manofold pressure. Should be around 0.8 bar tops.

If you have more then that, your exhaust will be to restrictive.

 

Oem NA cat is 400 cells i believe.

Turbo cat is 300 cells.

Sports cat (miltek, larini, tullett) is 200 or 100 cells.

 

As for durability, it's pretty much unknown if an oen cat can take much SC abuse. Most oem manifolds get cracked at some point. Then it's either a tullett manifold, or a dbilas casted manifold.

 

Edited by smiley, 18 January 2017 - 02:11 PM.

[alexb]

From experience. I went to stage 2 SC about 80K kilometers ago with completely standard NA exhaust. Got 0.8 bar boost, like Smiley mentions above, and according to OBD Tuner measurement just short of 250 HP. At some stage I put a tubby backbox on. No difference that I could feel. Sounds a bit better, but still crap. I did remove the prekat btw. No issues with the kat. The OEM stuff is not bad at all. But I have to say that the one thing I'm missing from my car is the sound. On the other hand, never had to worry about noise limits and would rather spend the money elsewhere

[smiley]

Was 2016 your second SC year Alex?

How many trackday did the oem cat get now?

 

[Acidpopstar]

Mine was standard apart from Larini back box. Made 259bhp according to OBD Tuner. Sounded great as well. Now changed to full decat Larini pipe with tubby back box due to the most recent crash I was in Wish I still had the standard pipes and cat and Larini back box as I've gained nothing but lost the sound Sent from my iPhone using Tapatalk

[bladerunner]

Thanks for all the replies. It seems that the standard system (minus the pre-cat) will not restrict power to the point where pistons and rods would have to be upgraded anyway ? I could never justify the cost of a Tullet system so this is good news. At some point I will probably make up a link pipe with a sports cat as I don't think it would be that difficult.

[alexb]

Was 2016 your second SC year Alex?

How many trackday did the oem cat get now?

 

 

SC'd August 2012. Really had to go back in history to find that. At around 27K. About 110K on the clock now. First track day was in 2014, so say 15-20 track days in total. Doesn't get the same abuse you're giving it. But I have to say that with the exception of the bolts, the OEM stuff is pretty well made. Still trying to convince my wife that the old NA backbox has to go on the wall as a piece of art, but she's resisting.

 

Must say that I covet (hear that Clarice?) a Tullett manifold. If only there was some kind of window at the back so that you could look at it once installed  

[smiley]

Pistons advised upgrade near 270, rods near 300, and liners near 400.

 

[pete-r]

If your running 265+ on standard internals you've potentially got a time bomb as mentioned. If you want to go faster on a standard engine your only option is via gearing. My odb numbers vary on power runs between 250-260 but I haven't weighed the car accurately etc. I had an OEM system with Larini when I first did the sc and got broadly similar power to now, but I later changed the manifold to a Thorny equal length and the cat to a piper sports model. Torque went up by a useful amount but power didn't really change, that said I do run the OEM rev limit so there may be more left on the table but I'm happy to protect the lump. PS Also I'll second the opinion on the noise on the Larini which has always been superb. Nothing pops and burbles better but with the full system now it's pretty loud to those not used to it.

Edited by pete-r, 18 January 2017 - 04:51 PM.

[Captain Vimes]

Same here as Alex: oem manifold and downpipe with precat removed and turbo back box. Key difference is that I swapped from a straight through back box to the turbo one and it also made no difference to the power measured in obd tuner. TBH I didn't like the sound of the straight through exhaust with the supercharger. I prefer the subtle nature of the turbo box despite the MASSIVE weight penalty.

[vocky]

Pistons advised upgrade near 270, rods near 300, and liners near 400.

 

don't you mean ....

rods near 270, pistons 300 and liners near 400

 

ps: 245-255bhp with a standard exhaust, no precat

[smiley]

 

Pistons advised upgrade near 270, rods near 300, and liners near 400.

 

don't you mean ....

rods near 270, pistons 300 and liners near 400

 

 

 

yes....

[Chris P Duck]

Seems I'm doing it backwards to everyone else! Tullett manifold, 2.5" downpipe with 200 cell cat, 2.5" Ubend to de-restricted tubby backbox. ~255bhp on OBD Tuner with standard rev limit.

[bladerunner]

Seems I'm doing it backwards to everyone else! Tullett manifold, 2.5" downpipe with 200 cell cat, 2.5" Ubend to de-restricted tubby backbox. ~255bhp on OBD Tuner with standard rev limit.

So is it the standard pulley size that restricts the power to around 260 bhp ? Or is it also cams and the flow of the head ?

[Chris P Duck]

Seems I'm doing it backwards to everyone else! Tullett manifold, 2.5" downpipe with 200 cell cat, 2.5" Ubend to de-restricted tubby backbox. ~255bhp on OBD Tuner with standard rev limit.

So is it the standard pulley size that restricts the power to around 260 bhp ? Or is it also cams and the flow of the head ?

I assume improvements in any area would yield some gains, pulley size would see the biggest gain as that's what most change to go "stage 3" (~300bhp). Not been tempted myself though as it means opening up the engine to do rods & pistons.

Edited by Chris P Duck, 18 January 2017 - 05:49 PM.

[MartinS]

Just do the pipo mod on the back box for a bit better tone and a bit better breathing.

 

Martin S

 

 

[CHILL Gone DUTCH]

 

Seems I'm doing it backwards to everyone else! Tullett manifold, 2.5" downpipe with 200 cell cat, 2.5" Ubend to de-restricted tubby backbox. ~255bhp on OBD Tuner with standard rev limit.

So is it the standard pulley size that restricts the power to around 260 bhp ? Or is it also cams and the flow of the head ?

 

 

there is to many variants to put it down to one thing 

IAT also play a big affect