Xsi horrendously down on power.

[Matt]

Right I have an issue. My xsi is seriously down on power, had a little thing of the lights with a fiesta that had been up my arse for last 4 miles, it was a mk3 si which is a 1.6? Any stupidly standard even standard exhaust etc, and it was by my side, surley they are not that quick?! Or mine is seriously dying.
What could cause my loss of power?

And before anyone says it (fooby) no '6 shit haha.
I believe I have a small blow in the Mani/cat join, also possibly a small hole in the exhaust. It's overdue it's oil change etc. but would this cause it to lag? What about a change of spark plugs? Would that make a difference? I really don't understand why it would be the same power as a 1.6 lol

[Scott]

They're a bit lighter if I remember correctly, but yes a leak on the manifold will change the exhaust pressure, which could make it down on power. Not sure what power those fiestas should be making though.

[Niall]

You would be surprised how much of a difference a good service can make!

Not loosing any oil are you?
At the moment, when I pull off the lights, because the cylinders have been filling with oil, it is horrendously dead....I mean my old 1.0 106 was faster off the lights. Once it burns it all off it's better but still not what it was!

[spike2002]

Blowing mani wont be helping get that sorted and give it a good service oil air and fuel filters exc

[4WayDiablo]

You don't know what's been done to the fiesta though!

I had a race with a fiesta and we were side by side up until xxx MPH
Later found it had a remapped 1.7 puma lump in it lol

Get it on the rollers if you really think its that down on power or borrow a mates xsi for the weekend

[Matt]

The fiesta is running 90bhp I did think the power to weight ratios would be a factor. I don't seem to be loosing alot of oil through being burnt/going in the engine I loose it mainly on the floor through my dodgy sump lol.
Think a good service is on the cards for next week. And got to fit my gti exhaust mani soon as soon as I get the heat shields do hopefully that will free up some ponies again. Other than that I'm stumped

[Niall]

Phil there's no need for rollers. If its down on power, it's something you notice! As said, try a good service to start with.

Are you running the original cat?

[spike2002]

Run a gti cat :p

[Matt]

Will have a gti cat when the gti mani goes on, but ATM I am running an 11month old cat

[samass]

Full service should help, pattern cat? That might be holding it back

[Matt]

It was okay, it's only recently it's started lagging, do don't think it's because of the cat. Although it could be filled with oil lol

[Dum-Dum]

Some of the mk3 Si fiestas came with a 1.8 zetec 16v engine and iirc were 100-110bhp

so 110bhp in say 900kg = 121bhp/tonne vs 306 XSI 140bhp in 1200kg = 112bhp/tonne

[Matt]

Nope it was the 1.6 16v 90bhp one. But I'm guessing even that still would be similar power to weight ratio as the xsi. Can see why he kept up for so long

[Ed Doe]

*AHEM*

[AdenoidsOOOOOOOWWWWWWWww]
Fiesta 1.6: 976kg, 101bhp. Power to weight: 103.5 bhp/tonne
306 XSi (AC): 1160kg, 135bhp. Power to weight: 116.4 bhp/tonne

Factor in servicing, reduced back-pressure from the straight through exhaust reducing low-end & midrange torque, the fact you're hauling a sub etc about, gear ratios (IIRC the xsi has a very long 2nd, meaning there's a bit of a gap between 1st and 2nd?) and its not unresonable to expect the fezza to be hanging onto your coat tails...

My old flatmate at uni used to have the older 1.4 ghia model, and it really did go like shit off a shovel, I was mildly shocked! It was embarassing at the time, I made sure I was never out in the dt (with only a stage1 tune at the time) at the same time as he was out, for fear of being shown up! lol
[/AdenoidsOOOOOOOWWWWWWWww]


Or it could be you can't drive.


And it's almost certainly that you don't have a '6....

[Eeyore]

Mines blowing ont he centre box but it still feels just as fast as always.

**Awaits ohhhh its a 1.8 though... even walking is quicker!**

[Matt]

Factor in servicing, reduced back-pressure from the straight through exhaust reducing low-end & midrange torque,

My straight through will be causin me to be slower then?

Need an excuse to put the standards system on lol

[Ed Doe]

Mines blowing ont he centre box but it still feels just as fast as always.

**Awaits ohhhh its a 1.8 though... even walking is quicker!**

Depends where it is on the centre-box, but in general reducing back-pressure will marginally reduce low-end and mid-range torque, but will marginally raise top-end power, as the engine can expel gasses more easily.

Depending on the size of the hole, it will affect it to varying extents, and it's doubtful you'll 'feel' the loss, as it will feel 'quicker' at the top-end. However, the area under your 'power graph' may be marginally smaller, meaning overall acceleration may actually be less.

The effect will be minimal really, even if you're running with a hooting split pre-cat and it sounds like the earth is literally ending, but the difference of a few hp there, coupled with a few lost through needing a service can easily reduce the power to weight ratio, and as I said, gear ratios play a big part in acceleration. That's why gti6's with 'only' 167hp are still not too far off, and in some cases quicker than much newer more powerful stuff like golf gtis and type r's. But it's also why they literally suck balls at economy; the box is so short!!!



Yes Matt, your straight-through back-box will be reducing back-pressure and will reduce your torque as above. I'm sure its the same thing with the eXceSs-pie, but the standard '6 exhaust was certainly very well designed out of the box, and it works with the induction-side to aid mid-range torque whilst also flowing well for the power. There were a whole load of threads about this a while back on the '6 forum. Unless your cammed and bodied to buggery, or boosted, you don't really need to run a less-restrictive back-box...

EDIT:
Had a quick look for a couple of the threads about it:
http://www.306gti6.com/forum/showthread.php?id=141587
http://www.306gti6.com/forum/showthread.php?id=146944

[Toms306]

XSi's are fairly slow as standard tbh.....but if you really think its down on power, definitely give it a good service and see what its like from there...by a good service I mean check everythings tight and not blowing etc rather than just an oil and filter change lol.

However I agree with the above....sometimes you see cars out that look fairly standard, and may even have badges indicating they're only the 115/130bhp model.....but really they're hiding something.

[Ed Doe]

blahblahblahblahblahI'vetotallymissedthepointandnotreadallofthethreadbutmygolfpd130isthedogsbollocks/thread

why thankyou for your input there Tom :roll:

[samass]

blahblahblahblahblahI'vetotallymissedthepointandnotreadallofthethreadbutmygolfpd130isthedogsbollocks/thread

why thankyou for your input there Tom :roll:

[Dan!]

Bwarrrrp POWWWERRRRRR GTI6 woooyeah

Thanks for yours aswel ed :roll:

[Ed Doe]

Lol, FYC Dan! I've contributed loads of genuinely useful info to this thread!!! Unlike my usual drivel!

[Matt]

Cheers ed gave me something to read while trying to stop myself from ripping my eyes out at work. Looks like I'll be chucking a standard exhaust back on it and see if anything is different, need a weekend at curts lol.

Once I've given it a service, fitted gti exhaust Mani and cat, new engine mounts, all the usual gaskets hopefully I'll see a difference

[Ruan]

Turn up the boost?

Oh wait...

[mark_airey]

Fit a turbo..........Turn up the boost?.............[/thread]

Edited for accuracy as this would fix the problem of it being slow

[ginge191]

Turn up the boost?

Oh wait...

repped!!

[Dave]

Bwarrrrp POWWWERRRRRR GTI6 woooyeah

Thanks for yours aswel ed :roll:

Best post ever dan!!!!




Ill get back to the diesel section...

[Scott]

:lol

contouring from toms point about being badged up incorrectly, remember curts vag has 6 badges

[Matt]

Hmm didn't look like it was badged incorrectly, unless it was a proper sleeper. Really dirty on steels one hub cap. Looked like a pikey driving

[Midnightclub]

Bare in mind matt.. it is a ford.. and rust is lighter than carbon fibre!