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Discussion Starter #1
Guys,

I've made up my mind. The XR8 ute is an absolute slug down low. Doesn't have that omph feel about it until it hits say 3500RPM. After that...its sweet!

My catback is only dual 2.25 so I don't think back pressure is the issue. (Although the front section to the first muffler is dual 2.5 inch).

Would it be worth changing the front section to dual 2.25?

Will the helix spacer give better down low? Will extractors?

Does anyone else have this opinion of the BA XR8s?
 

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More horsepower required
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Extractors coupled with an air intake definitely make a difference with regards to low down power. The helical spacer is hard to guage so far as its power increase , but it does make it more responsive , as i've removed mine and noticed the difference straight away.
I did the whole lot in one hit , and afterwards was like driving a totally different car.
I think the new pacemaker extractor primaries are 1 5/8 whereas mine and a alot of other blokes in here have the Herrods ( Defillipo ) 1 3/4 primaries from memory.
 

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Hey fullthrottle is yours a auto or manual.IF its an auto that would explain why.Its different in the manual.But yes even with the manual i think to myself too its a bit slow down low but that is due to the diff ratio.It has plenty of power but it doesnt get there quick enough.The thing I suggest is a ratio change .Ive been meaning to look in to it for myself .What it really needs is somthing like a 3.7 ratio and the will fix the problem.
 

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Falcontastic.
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Is your car an auto,most stock auto's are slow down low untill this area you described 3500rpm maybe you should look at the diff gear's,to get a real kick in the pant's feeling down low you are going to have to do more than just header's.
 

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Falcontastic.
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Sorry 330boss you beat me to it,but we were thinking along the same line's.
 

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Discussion Starter #6
Its a manual...

Will changing the diff ratio mean shorter gearing? I dont want to change gears 4 times to reach 100km/h.
 

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fullthrottle said:
Its a manual...

Will changing the diff ratio mean shorter gearing? I dont want to change gears 4 times to reach 100km/h.
why not.If you are thinking it will slow your 1/4 mile time you are wrong.I draged mine and im still in 3rd when i cross the line and thats when i realized that it needs shorter gears.Also its less strain on the engine becaus ethe gears will do the work instead of the load on the engine.Also In my opinion I think it wouldnt use anymore fuel because my ute uses the least about of fuel at about 75km seeing the speed limit in most areas is 60 it most probably be cheaper ob fuel.
Well im not too sure if 3.7 are avaliable anyway.
 

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greetings all
diff gears are a problem for the M86 rear end fitted to the BA V8s & the turbo at this stage there appears to be only 2 different ratios 3.45:1 & 3.23:1

as for the auto there is enother problem with the rev limiter if you change the diff gears but thats enother story that will raise its head in the not to distant future

regards
rod
 

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Discussion Starter #10
Are we talking hundreds of dollars or thousands of dollars or tens of thousands of dollars for changing diffs? In general....
 

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Someone had told me it cost around a grand thats fitted so I think its a pretty cheap mod compared to what people are paying for exhausts and cold air`s and spacers and shit.
I got a quote on exhaust extractors and cold air and its around the 3grand mark.And to tell you the truth I dont know if its worth it because the standard cars are no slower than the cars with these mods.
The power is already there , these cars are putting out near 350 hp .A 3.7 will make the car feel a hell of a lot lighter even a 3.45 would be sweet.There is nothing you can do to the car that will give it more oomph than to change the ratio.The sooner people realise this the sooner we will see some xr8`s doing some kick ass times.
 

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Discussion Starter #12
hmmmmmmmmmm

Recomend any places in melbourne I can start my enquiries?
 

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Pursuit Reincarnation Dog
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Forget the diff thing because I've been pestering Dana Spicer about this as has my diff expert. However, my understanding is Ford/FPV have built mules for future models which are running 3.7. Once these go to production the pinion and crown setup will be available for the aftermarket. I did some calcs and I reckon the 3.7 will slightly slow the 0-100 because of a 2-3 change, however the car should be a lot more sprightly everywhere.

As for mods versus dollars, I did the same thinking. That's why a blower kit at 8 gorillas is best bang for buck no questions! Unbolt in two hours max and put on your enxt car no one will know.
 

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X-DM!!
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It all comes back to the computer that runs the show. Until this can be changed we are stuck with what power it allows us. I saw a article in a mag the other day and a XR8 with a super charger fitted feels no differant up to 3000rpm than a standard XR8.
 

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Thats cause centrifugal blowers make power with revs but I agree with the comment about the computer. They must have torque limiters to protect the driveline.
 

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Movin!
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I think it's a mixture of everything said here. For starters dohc motors do tend to have a definate peak area, and also the fact ford has to leave room for series 2 etc in regards to ecu programming and power output. There is also the longevity of the drivelineto worry about, whereby they have to be confidant the parts have to at least survive the warranty period. Another thing, weight and gearing, as mentioned.

As for myself when i got the herrod extractors & cats back fitted, this instantly improved low down torque, as did the ss inductions, while the helix spacer improved the actual acceleration
 

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330boss said:
There is nothing you can do to the car that will give it more oomph than to change the ratio.The sooner people realise this the sooner we will see some xr8`s doing some kick ass times.
Seeing as you have no mods , your evidence comes from where ?
 

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greetings all
Rodderz i thought that you would have lost a little bit of low down torque with the extractor as they are quite a large primary pipe

i would have thought that with the 1 3/4 primary extractor you would have lost torque down low due to no back pressure but gained a little bit of power up top & with the extractors with 1 5/8 primary's the opposite would have happened

regards
rod
 

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Fordhead said:
Seeing as you have no mods , your evidence comes from where ?
OK if we are talking XR8 utes .The fastest ute with mods on this forum has run something like a 14.5.Even the sedans are around 14.2 as standard and then you get GT`s with mods only pulling 14.2`s.
I have run a 14.4 at 101 miles completely standard it was also on a 38 degree day.There is my proof.
There will be another street meet on the 6th of march hopefully it will be nice and cool as Im hoping to run a 14 flat.
 

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330boss said:
OK if we are talking XR8 utes .The fastest ute with mods on this forum has run something like a 14.5.Even the sedans are around 14.2 as standard and then you get GT`s with mods only pulling 14.2`s.
I have run a 14.4 at 101 miles completely standard it was also on a 38 degree day.There is my proof.
There will be another street meet on the 6th of march hopefully it will be nice and cool as Im hoping to run a 14 flat.

I'm asking for proof about gearing seeing as none of us realise it as you so put it. Spending money on exhausts and intakes isn't neccesary either so you say . I'm very keen to hear about your gearing mods and KICK ASS times in these cars . There is only one man in here I know of that has changed his gearing , and he'll tell you there wasn't too much kick ass about it. In fact , it created a problem all of its own ( read rods reply in this post )
Most blokes in here who own either pursuits or XR8 utes know that the ECU is the key to these cars , and until it can be edited , the present mods ( exhaust/intakes etc etc ) aren't being fulled realised .

By the way , I don't mean to put a downer on your next drag meet , but keep hoping , pray if you like , but 14 flat won't eventuate for you unless you are on a dragstrip with a downward slope.
 
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