[Jase_ELXR8]

On the weekend i fitted a new exhaust to my 97 XR8. I fitted EL GT headers and cats and then 2-1/2 inch stainless with one muffler. On Friday i ran it up on a Dyno dynamics dyno and got 113kw. Today when i ran it i got 108kw. I've lost 5kw and my tractive line is also lower than what it was with the original exhaust.

Anyone got any ideas???

 

[botch]

could be air temp difference??????

 

[Jase_ELXR8]

Not sure, Friday and today were around the same temp. The dyno adjusts itself for humidity etc... Could air temp cause that much of a difference??? It's a fair bit considering you should gain by putting an exhaust on...

 

[XtRmn8]

Dont tell me that your XR8 has 113rwkw because that is 2rwkw more them my EL IL6.

Hmm funny!

 

[XR8chic]

Is it running on all cylinders??

When my ED only had extractors, and a 2.5" exhaust it had 119rwkw

 

[Jase_ELXR8]

i cant tell you it has, because it doesn't anymore it got 108kw now!!! Not happy Jan...

XtRmn8 - Have you done any mods to your EL??? 113kw is about right for my car stock. 170 at fly less about 34% thru drivetrain = 112.2kw....
I was not happy today when looking at the numbers....

 

[Jase_ELXR8]

Is it running on all cylinders??

When my ED only had extractors, and a 2.5" exhaust it had 119rwkw

Yep running on all cylinders (new plugs 2000kms ago. Old one looked like everything was running fine) Air/fuel ratio today was mid to high 12's which is the same as the runs on friday...

 

[RATT]

Have you tried a different dyno?

I read somewhere that it is rare to find two dynos showing the same kw at the wheels on the same car, even on the same day.

What about the "seat of your pants" test, does the car feel quicker?

My thoughts anyway.

 

[Mr Sparkle]

Yeah that sounds too low mate.. my EL2XR8 was getting 120kW at the wheels fully stock, which is around the expected figure, but a little low. With the exhaust + extractors I got, it's now 140kW at the wheels, so 113 with your setup don't sound right!! :thumbdown:

I agree with the lads, you should try a different dyno.. but just remember to keep on the same one between mods otherwise the readouts are next to useless

Yours is a series 1 EL I take it?

 

[Jase_ELXR8]

Yeah that sounds too low mate.. my EL2XR8 was getting 120kW at the wheels fully stock, which is around the expected figure, but a little low. With the exhaust + extractors I got, it's now 140kW at the wheels, so 113 with your setup don't sound right!! :thumbdown:

I agree with the lads, you should try a different dyno.. but just remember to keep on the same one between mods otherwise the readouts are next to useless

Yours is a series 1 EL I take it?

Yep, series 1. It's the same dyno at the same place. Somehow by bolting on this exhaust i've managed to lose 5kws over the standard system!!

 

[ebxr8240]

Was the muffler itself a high flowing one?

 

[Jase_ELXR8]

i would assume it was because of where i got it from. I don't really want to say where i got it from at the moment, coz i'm gonna speak to them tomorrow and see what they think. I think i might have a bad muffler or something but not sure. It still revs out ok though....

 

[Martin]

You didnt put some cheap ass exhaust system from 'Joes Mufflers' on it did you? A 2.5inch Press bent will flow no better than a 2.25 mandrel bent, which is only a 1/4in bigger than stock.

IMO a 5.0L V8 (even in stock trim) requires atleast a single 3in or dual 2.25.

 

[XLR8]

what mufflers did you use??

 

[Jase_ELXR8]

You didnt put some cheap ass exhaust system from 'Joes Mufflers' on it did you? A 2.5inch Press bent will flow no better than a 2.25 mandrel bent, which is only a 1/4in bigger than stock.

IMO a 5.0L V8 (even in stock trim) requires atleast a single 3in or dual 2.25.

It wasn't a cheap ass system and it is a good quality muffer. As i said before i dont want to post were i got it from up here, purely because this is a problem and i will work with them to find out why this happened. They can't beleive it either.

 

[Jase_ELXR8]

here's the dyno graph
Before exhaust in red, after in blue.

 

[laminge]

mate

are you sure everything was tightened up properly?

Have all the sensors been replaced in the right spot

Could it be there is a restriction somewhere in the exhaust?

 

[XLR8]

Pi##ed off about the power, but you must be happy how it sounds???
EL's are too quiet standard.

 

[Jase_ELXR8]

yeah it sounds unreal. They've done really well in that respect....

 

[Aussie Pete]

yeah it sounds unreal. They've done really well in that respect....

All noise - no action though. I must say I am very surprised at how poor these cars are in RWHP. Compare some of the V8 readings to some of the I6 Falcons out there that are basically stock and you wonder whether some of these windsors aren't a bit sick.....