another exhaust thread

[Darkhawk141]

xforce

Are the xforce exhaust systems for sv6 series 2 any good?

 

[kingyinperth]

Ok for Duaned, Pir4te, Kingy P and anyone else who's interested:
My Redline now has fitted an E3 GTS headers & cats, and the 2.5" VF GTS catback, and STANDARD VF Redline AFM/Auto spec diff tail pipes/mufflers. It sounds nice, without being too loud, and there is no hint of drone at any speed in any gear. It's probably loud enough for me but I might tray a J Pipe at some point, just for comparison.
Today I picked my car from GenTech in Canberra after an engine and tranny tune. The results are pretty good, the car has a much broader torque curve, now making more torque at 3750/4000rpm than it previously did at 5000rpm. Both torque and kW have increased markedly. It's sitting somewhere around 310flkW. The push in the seat under WOT acceleration was always there, but it's now far more aggressive.
I'll hold my comments on the Gentech boys for a few more days until I really get a feel for their workmanship, (i.e no issues!), but if first impressions are anything to go by (having driven home form Canberra today), the Gentech tune is GRRREAT! Oh and the no bull customer service was good too. They told me the good, the bad and the ugly (mostly good). But they did say my OTR CAI (brand beginning with Oh?) and standard E3 HSV headers were robbing around 10-12kW, and they found it hard to keep the temps down and get any cold air into it which was affecting the tune. For me I thought my car had picked up power and torque a little with just the CAI and no other mods or a tune, but perhaps it was just the perception of more power from the induction noise? However it certainly went better with the HSV system fitted. The tune has added much, much more again. Anyway it goes hard, is easy to drive, has torque to spare, and when you give it a squirt, the smile always follows. The verdict...I'm very happy with the exhaust, headers, CAI and tune! It was good standard, but for this has brought the growling 8 alive! Total cost to date $2,100

Tried to upload a couple of very short movies form my iPhone but the files are too large. Will have to compress them I suppose or start a Youtube account? I have one inside one out of the car. Poor sound quality and camera skills, it sounds much better than the vid but you'll get the point.
I'll try again tomorrow.
P.S - Timed 0-100 today in D, around 4.8 - 5.0 +/- 0.2 would be a touch quicker using sport mode

Nice work buddy,had a listen to the sound clips..sounds sweet mate :smoking: Nice gains made,excellent BFYB too!

 

[Ian Johnston]

duaned, 50kw at the engine is quite possible, and thats what he has gained, not at the wheels.

 

[Not_An_Abba_Fan]

I'm a bit puzzled as to where the $2K comes from, weren't all your parts second hand?

For maybe ~$1K extra, you would have netted close to 100kw over stock. $2460 for headers, cats and the system, plus the tune.

Just trying to work out what is more value really and to compare all the costs.

 

[426Cuda]

Duaned,

You may be right about the overzealous power claim, but I think I'm about on the money. It's not 240rwk its 230. But if it was say 190rwkw standard, then that's a 40rwkw gain, multiply 230fwkw by an estimate of say 1/3 power loss, and that gives around 306fwkw. I was told that a 307kw Aw LS2 is 230rwkw, so my assumption is that it's approximately 305-310fwkw.

NAAF
Current:
$310+248 = $558 (headers, cats and 2.5" VF system)
OTR$500ish
Tune$990
Total $2,048

Result - 230rwkw

Your Exhaust Manta $2460
OTR $500
Tune $950
Total $3,910

Result - 270rwkw?? Maybe

So the difference is in the cost of the exhaust or $1,862 for 40rwkw. I believe there's room in my budget to get better than that and save at least $1000 after tweaks. The main one being a set of 200 metal cats, with 2.5" intake tubes. In essence I believe that after this mod, the differences in the exhausts will be negligible.

Having said that, I think your system is excellent value, and compared to the W310, superior bag for your buck, i.e 362fwkw for $3,910, compared to 310 for >$6K. For those in the market you could probably achieve that and a cam for the same price as a W310...
There's still a market for the W310 though, and it's squarely in the new car buyers / warranty conscious segment.
Cheers

 

[Ian Johnston]

A 307kw VE LS2 will make about 220rwkw, a VZ 297kw LS2 will make about 235rwkw.

* Both autos*

 

[426Cuda]

Yeah, both very different autos...The VF A6 is supposed to be better tuned etc so if anything the loss s/be less.

Can anyone throw some accurate light on the likely FWKW from a VF A6 with 230RWKW?

 

[426Cuda]

Torque was the big winner. Went from a peak of around 395Nm at 3800-4500, to ~445Nm at 4500, with huge area under the curve compared to pre-tune. If I'm not mistaken that around 600Nm at the flywheel! Up from 517 standard.

 

[Not_An_Abba_Fan]

For the record, when calculating drive train losses, you work out your original drive train loss from the stock power, then add that same figure to your increased power figure. Drive train losses are not really a percentage of the total RWKW when you have gained power, it is a constant. Just because your power has increased, your drive train loss hasn't.

Using your example, originally you estimated 190 rwkw, if your drive train loss was 27%, fwkw would be ~241. Use 51kW as your loss figure. It doesn't change just because you have increased engine power, you haven't change anything in the drive line. So, you are now at 230rwkw, plus 51 would give you ~281fwkw. Not the 27% which is 62kW. You drive train can't magically find or lose anything just with an engine change.

 

[426Cuda]

Yep good point the power loss is relatively constant, but not necessarily linear, and not reflected the same on different dyno runs. Obviously there are other variables e.g where peak HP and TQ are occurring on the rev range, how the dyno is set up, atmospheric conditions, fuel type, which gear the tranny is in, tranny oil temp, angle of the dangle blah, blah. I disagree with using 27% to calculate fwkw though.
If I had a 70kW power loss through the drivetrain at standard, which is what I'm led to believe, then 70/260 * 100/1 = 27%, but it's flawed maths to then say 190*1.27 =241fwkw. That is because the denominator is now 190, not 260, so the power loss (70kw) is 36.8% of the denominator. To prove this 190kw * 1.368 = 260kW. Therefore 230 * 1.368 = 315kW. But this is wrong also because as you point out it is more accurate to add back the power loss from standard, which is 70kW, so 230rwkw + 70kW = 300fwkW. Again this is assuming a linear power loss. That equates to a 15.4% power increase over standard at the flywheel, or 21% at the wheels. I had 190rwkw, and now I have 230rwkw and that is a 21% power increase.

Do you have any dyno sheets showing how you've achieved 270rwkw with an exhaust, (inc extractors and cats), tune and OTR? Based on what I've achieved that is a big increase i.e 42% over standard. certainly what I'm chasing and hope to achieve with my cat modifications and re-tune. But it would be good to see that it is doable without any further mods.