Best upgrades for power xr8

[xr8fg]

What’s some mods I can do to get more power out of my xr8 fg I’ve already done intake exhaust system and headers and cats


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[fnp]

Tune is the most obvious and under drive pulleys are the most obvious. Past that it's not very good bang for your buck keeping it NA, but you could do bigger throttle bodies, intake plenum, cams.

[Mechan1k]

Kenne Bell LC supercharger

[ebv8]

diff gears
if its auto its got a 2:73 so go a 3.46
if its manual its got a 3.46 so go a 4.10
my ba gt 290 has 4.1's and its rips, totally different car to drive than my auto ba xr8 with 3.46 gears

[Prymawl]

Yeah im in the same boat as OP
I have 2010 boss290 and looking at cams and intake plenum.

All i can find is a yella terra side entry and a bpt front entry plenum with no reviews or power gains for either...and as for cams its either crow cam or herrod...again not much on gains and the opinions are varied

[agmonz]

Originally Posted by ebv8

diff gears
if its auto its got a 2:73 so go a 3.46
if its manual its got a 3.46 so go a 4.10
my ba gt 290 has 4.1's and its rips, totally different car to drive than my auto ba xr8 with 3.46 gears

Agreed. Best bang for your buck.
I have 3.73 gears in my FG XR8 with 6hp26 trans, and it is awesome.
I added a high stall converter after that as well, and really enjoy that.
Depends a bit on what you are wanting, but both these mods work well on the street.

[TICKFORD220]

Totally agree on diff gears,boss motors need diff gears to make up for the lack of low end torque.
I had 4.1 gears in my t56 ba xr8,was really fun,as a comparison my manual fg xr8 (stock 3.46 gears)feels like a slug compared to my old ba xr8 with diff gears.

[fnp]

I'm reluctant to do cams personally. Expensive and minimal gain plus I don't want to loose any lowdown torque. I like it cruising at 1600rpm at 100km/h too so I don't want to do diff gears.


Leaves me thinking I've gone about as far as it will go N/A unless it one day needs a teardown and rebuild then I might throw some internal goodies at it.

[Prymawl]

What have you done to get to your rwkw number?

Mine has herrod cai full exhaust 3 inch single and tune dyno says 275rwkw and 650 nm i bought it like that but im looking to go bit morei like the idea of over 300rwkw.

[fnp]

Mod list is:


- 2.5" Manta quad
- 200 cell cats
- Genie Tri-Y headers
- KPM/Streetfighter CAI
- 25% under drives
- Plenum phenolic spacer
- And a tune to tie it all together


If I do anything else it would probably be a plenum and throttle body upgrade but it's not great returns for the money. I've kept the factory 5900prm rev limit but I could have taken it up to 6500rpm I guess (it's still making power at 5.9k) but I don't really see the point just for a peak number. Fairly tough to crack 300rwkw NA with bolt-ons with these things I reckon.

[Prymawl]

Hah awesome..can you tell me more on these under drives..all ive seen so far is people do it and then oil pump breaks??
Also have you replaced atock clutch? And have you had the where the T6060s pull the clutch pedal to the floor..something to do with concentric slave cylinder,, i experiemced this for the 1st time 2 days ago...was a bit weird

And yeahbbi agree parts arent cheap n dont have big gains but
i guess thats the nature of it all going NA

[fnp]

I'm still on the original oil pump @ 215k. It might be bit of a gamble but from what I understand it's not so much high RPM that kills them it's rapid changes in engine speed like limiter bashing.. so you know don't do that. Having said that if I ever had the timing cover of it I'd be doing the pump just for peace of mind.


I'm on my second stock clutch, at 195k exactly that happened to mine, slave cylinder leaked (probably a 10c o-ring!) and a lot of mornings the clutch would be on the floor with no pressure. Topped up the clutch fluid, pumped the **** out of the pedal to rebuild pressure and spent the day driving not using the clutch apart from a dead stop. Drove around like that for two weeks before I could get it into the shop.


Ford in their wisdom have put the slave cylinder inside the bellhousing so you may as well replace the stock clutch if you do need to repair the slave.

[Prymawl]

Yeah fair enough make sense about oil pump.

And that cant have been good for gear box.
Uours the t6060 yeah? Does your 1st 2nd n 3rd gibe you hassle sometimes? Like its notchy somedays and smooth as butter the next?

And yeah i have lined up a clutch from ACE that comes with a metal concentric slave.
Did you swap your clutch yourself or take to a shop? Curious on labour cost.

[fnp]

Gearbox was fine, clutch had a lot of oil on it though. Luckily it was nearly gone anyway so a good time to replace it. Slave cylinders are a known weak point on them, wish I had replaced it with one of the Mal Wood alloy ones now.


Mine shifts fine most of the time but on occasion at a dead stop the synchros don't quite line up for first and I have to select second then first. I wouldn't say the gearbox is slick but not notchy either, just a typical Tremec. Apparently changing the oil to Penrite 70w75 makes them shift a bit nicer than the factory spec auto trans fluid. I'll be trying that on my next change.

[Metalad]

To be honest the best thing i have done is 4.10 diff gears, i have a 302 with a 6 speed manual huge cams and harder valve springs, billet oil pump and the usual exhaust and intake upgrades making 301 rwkw, it was all nice enough until the diff gears went in and then it really freed up and came alive. they may not be for everyone, if you do hwy everyday prob not great but i use mine everyday in stop start traffic and its better on fuel not worse in that situation. i paid 580 for spicer gears and 1200 to have them fitted.

Oh and FNP i had the same issue with my gearbox not going into first sometimes, i put the penrite gearbox oil in and it has almost never done it since.

[Prymawl]

FNP good info LAD nice work confirming this. My clutch is nearly fried im hoping my ace option 3 plus shows up next week, and i can get it fitted soon after..best quote i have is $420 labour (yeah i know) including clutch fluid, i will see if they will swap oil to your penrite reccomendation. Diff gears not really ideal for me personally i like the jeckyl n hyde thing it has goin on, a beast in 1-4 and calm n quiet 5-6 plus the fuel consumption in 6th is fluctuates 6 to 10L/100 1700 somthing rpm at 110 on level road

[fnp]

With you on the diff gears, not my cup of tea either.

Labour doesn't sound too bad, it's a big job.

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[Prymawl]

Also going to be talking to my tuner next week. I asked him he can crack 300rkw he reckons a cam will do it but we will see,im looking at the front entry intake plenum and one of those 62 mm (from america) or the mustangs 65mm billet throttle body for **** factor coz its shiny 😝 ...but again ive heard after market TBs can be a pain to tune. But ill see what he says🤞


https://www.fordracingbyspeedshopdir...Code=M-9926-3V

[fnp]

Yeah I like the look of them. I'd like to get one of the YellaTerra plenum and twin throttle body setups only because I want the car to look as stock as possible and they do a good job of that. I think the tuning is not such a big issue as long as you have a decent tuner.

I have read that the twin throttles are nicer to drive for a street car but the monoblades can give slightly more peak power at the expense of drivability. Not sure how much there is to that.

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[fnp]

Just looking around at plenum setups a bit more. YellaTerra have a dyno showing a 17rwkw increase on their website. The BPT front mount plenum doesn't mention power gains but I did notice it uses twin 60mm throttles compared to the YellaTerra twin 68mm setup (then again, size isn't everything, as all us blokes know). BPT did my tune so maybe I should speak to them about their plenum next time I'm up there.


At low engine speeds torque is actually aided by a larger port size and the corresponding lower air velocity (one of the reasons 2V LS1s feel better low down than the 4V Boss V8s - one of the advantages of a 2V head is each individual valve is physically larger than the smaller valves in a 4V setup). Same reasoning is behind the broadband manifold on the Falcon sixes.


Also found a guy on YouTube who did the YellaTerra plenum with 60mm throttle bodies and a tune and he picked up almost 30rwkw. Another reason I like the look of the YellaTerra ones is it uses the factory locations for all the wiring looms/sensors/PCV etc. No need to dick around with them.


Damn it's tempting to get one now.... the 300rwkw is a nice mark to break.

[Prymawl]

BPT in WA? If so maaannn i hounded those peanuts for MONTHS to get an answer from them they come back with $1800 for the plenum alone and that they got 40 more HP with THERE custom tune....and thats all i got..to me that vague as it comes..HP at the fly or wheels,was it a boss 260 or 290..was it 3V or 4V was it a stock motor did it have an exhaust setup...questions they cant or wont answer...1800 for a bit of ally is alot of $$$, made worse by no proof of gains.
I mostly want a front mount for pure **** factor and aesthetics, but if it the tuner doesnt agree then ill go straight to yella terra and get theres with twin blade������

I spoke to another fella n he was saying twin blades are ok but the oval shape mono is what causes issues...aparentlyso theres conflicting statements there...nothing is easy hey haha

[fnp]

Yeah BPT in WA. Probably best to call them and have a chat, I've always found them pretty good to deal with.


It is pretty expensive especially considering you need to redo the inlet piping and a bunch of other stuff and personally I'm not that keen on the polished aluminium and front mount look which puts me towards the YellaTerra but hey each to their own.


Either way the car would be up for a tune with a new throttle body.

[Prymawl]

Originally Posted by fnp

Yeah BPT in WA. Probably best to call them and have a chat, I've always found them pretty good to deal with.


It is pretty expensive especially considering you need to redo the inlet piping and a bunch of other stuff and personally I'm not that keen on the polished aluminium and front mount look which puts me towards the YellaTerra but hey each to their own.


Either way the car would be up for a tune with a new throttle body.

Yeah see none of that is mentioned on the product
And none of it was mentioned when i was talking to them...bit weird that.

And thats it hey each to there own..my idea is to have the intake sysyem in a strIght line, like LS have, i like that look, but its just an idea at the moment

[fnp]

You can do a Boss OTR

[Prymawl]

Yeah i have the herrod one, thatll work with yella terra plenum if frontnentry doesnt work out