xr8 camshaft

nitroman · 18-06-2006, 08:48 PM

Hello au people, I've just bought an Au1 XR8 ex chaser.It's a ripper car with only 95000k on it owned by a super fussy owner after it was passed on by the feds. I've fitted a 21/2 inch exhaust which has made some extra power, but of course I need more! I've been given a camshaft from a "brute"V8 racing ute, but I'm not sure of it's grind\lumpiness and whether it will be compatible with my auto/ecu. I don't care if I lose some bottom end power because the power down low is super strong and seems to fade after 4000 revs. It pulls 210 kays, but really that's just not good enough! Can anybody share their experiences of "camming up" their XR8 and does anybody know the cam grind of a racing ute?

Craig · 18-06-2006, 09:14 PM

Unfortunately you clutching at straws with an unknown grind. I would never put a camshaft in an engine unless i knew the specs. Send it to crow cams and ask them to give you the specs.

I have fitted quite a few cams to the AU series, they work real well when combined with a little bit of head work, hi-stall convertor and decent exhaust.

Cheers Craig

JC · 19-06-2006, 02:07 AM

Cheaper option to get it breathing up high in the rpm range is to fit 1.72 Roller rockers (ST 2027s from Yella Terra), and at least a single 3", or twin 2.5" system. This combo acts like a new cam - standard rockers are 1.6 ratio, so you get 8% increase everywhere, which makes a large difference between 4000 & 5500. My AU1 is also ex-police, though I wouldn't have a clue if it was HWP, GD or what. Not every ex-cop car was a chaser - in fact, most aren't.

048oss · 19-06-2006, 10:37 PM

Quote:

Originally Posted by JC

Cheaper option to get it breathing up high in the rpm range is to fit 1.72 Roller rockers (ST 2027s from Yella Terra), and at least a single 3", or twin 2.5" system. This combo acts like a new cam - standard rockers are 1.6 ratio, so you get 8% increase everywhere, which makes a large difference between 4000 & 5500.

Is this the case with series111 xr8s?
I have a series 3 xr8 auto and have been less then impressed with the upper rev range power, the car is great around 3000 to 4500 but then dies in the *** after that.

xr8ute · 23-06-2006, 06:31 PM

Quote:

Originally Posted by 048oss

Is this the case with series111 xr8s?
I have a series 3 xr8 auto and have been less then impressed with the upper rev range power, the car is great around 3000 to 4500 but then dies in the *** after that.

The 220kw XR8 motors already have the 1.72:1 Yella Terra roller rockers.

IMO they die in the arese at those revs because of the crap std valvesprings, and the small std cam doesn't help either. The rest of the package (i.e. heads, intake, throttle body, MAF, injectors), especially on the 220kw engines, can produce stacks more power. Just need the right cam and some decent valvesprings.

5 FTR 5 · 23-06-2006, 06:37 PM

Quote:

Originally Posted by xr8ute

The 220kw XR8 motors already have the 1.72:1 Yella Terra roller rockers.

IMO they die in the arese at those revs because of the crap std valvesprings, and the small std cam doesn't help either. The rest of the package (i.e. heads, intake, throttle body, MAF, injectors), especially on the 220kw engines, can produce stacks more power. Just need the right cam and some decent valvesprings.

Ive put the crow cam 1371 with .533 lift and the standard springs that manage quite well a little edit and makes power to a least 5800 rpm before starting to drop.

xr8ute · 23-06-2006, 06:39 PM

Quote:

Originally Posted by ratio 3.99

Ive put the crow cam 1371 with .533 lift and the standard springs that manage quite well a little edit and makes power to a least 5800 rpm before starting to drop.

Fair enough, although there certainly does appear some "good" examples and "bad" examples out there.

Did BPT do the cam install for you? I wonder if they might have shimmed up the springs a little to increase the pressure...?

xr8ute · 23-06-2006, 06:54 PM

Cool. I have been trying to find out if the 220/250 (and even the 200kw) motors got the Ford Racing "GT40" valve springs, which are a pretty big improvement of the stock "gt40p/explorer" valve springs.

Are yours a single spring w/damper?

EDIT: Actually, being a crow cam, I suppose they are using a crow valvespring too...

5 FTR 5 · 23-06-2006, 06:58 PM

Quote:

Originally Posted by xr8ute

Cool. I have been trying to find out if the 220/250 (and even the 200kw) motors got the Ford Racing "GT40" valve springs, which are a pretty big improvement of the stock "gt40p/explorer" valve springs.

Are yours a single spring w/damper?

EDIT: Actually, being a crow cam, I suppose they are using a crow valvespring too...

Yes they are the singles.I thought they where not going to be any good and put the doubles in.If i go any bigger than .533 then i should look at the doubles.But being a daily driver I'll stick to this size.

xr8ute · 23-06-2006, 07:11 PM

Removing the head to get them machined for doubles is a pain in the ars3...

Nitroman, maybe have a chat with Chris on these forums. If I remember correctly, he used to do some preperation work on Nick Zucanovic's Brute Ute. He may know what sort of cam/cams they where allowed to run.

048oss · 23-06-2006, 09:49 PM

What power increase you guys talkin about?

5 FTR 5 · 23-06-2006, 10:29 PM

Quote:

Originally Posted by 048oss

What power increase you guys talkin about?

Depending on the setup you have it can vary.Ive got the flash tuner to help set it up.After Terry from BPT had set it up the Hp increased some but the torque went right up.And as they say that is what wins races.
I ended up getting from 14.1 to 19.92 on the strip with sad gear changes if things went better or a better driver may get 13.7 or abouts.So the extra 15kw might seem so much BUT the pushing into the seat from the extra torque is GREAT.

xr8ute · 23-06-2006, 10:19 PM

I went from 139rwkw to 161rwkw with Crane 2030 cam, springs, and YT rockers (no other mods), and I ran a 14.54 @ 95mph.

Now i am running 3.9's in the diff, and a full exhaust (pacey 4-1's and 3" single), and running 14.15 @ 98mph.

ReVd_uP · 23-06-2006, 10:34 PM

id hate to be the one to ask this question, but whats fuel economy like after one of these or similar cam is fitted?

5 FTR 5 · 23-06-2006, 11:46 PM

Quote:

Originally Posted by ReVd_uP

id hate to be the one to ask this question, but whats fuel economy like after one of these or similar cam is fitted?

I haven't changed my driving habit which is the occasional red line (each time i take it out) Im still getting 450 to 470 out of a tank depending on the red lights.But the motor has been tuned to the cam specs by BPT or if you dont im not sure what you would get.

ReVd_uP · 23-06-2006, 11:55 PM

well thats another tick for a cam upgrade,dunno if id risk leaving standard valve springs tho, theres no way i could be a$$ed pulling the heads of to get them machined for double springs...ill see how i go after the exhaust upgrade,

nitroman · 24-06-2006, 09:07 PM

Well, today I installed tke cam out of the race ute into my AU1 xr8. Its a ford motorsport grind with 220' at 50" and 498" lift. The description of the cam said "good idle, good low to mid range, peak torque at2500, max power at5500, works with auto".
I also installed a set of crane roller rockers. It's now a pretty grumpy mother with an idle around 850 rpm and the power kicks in at 2500 and pulls strong to the limiter . Off idle take off has been killed though, a stall converter might be the answer. I also am thinking of getting a multi keyway timing chain and retarding the cam 2 or 4 degrees to improve the bottom end power. Oh and I was pleased to note when the rocker covers were off that my engine has gt40 cast in the heads. Any ideas on where to go from here people?

xr8ute · 25-06-2006, 11:45 AM

nitroman, that will be a Ford Motorsport E303 cam, certainly a good improvement over stock. Did you change the valvesprings as well?

A higher stall converter will help heaps...first gear in the auto is sooo tall, can make them feel like a slug off the line. Did you check the cam timing when you installed it, or did you just install it "dot to dot"? Sometimes the the pin on the end of the cam can be in the wrong spot and can actually be a few degrees advanced/retarded even though the timing marks are lined up properly.

Assuming the cam timing is straight-up, I would get the converter rather than muck around with the cam timing.

Any chance you will take it to the track for some 1/4 mile runs?

BTW, you will have GT40P heads which are a bit better again than the GT40 (better exhaust flow, and with smaller valves).

nitroman · 25-06-2006, 08:27 PM

That's correct, it is an e303 cam. I haven't as yet installed stiffer valve springs, and yeah I only lined up the cam "dot to dot" so i'm gunna invest in a rollmaster or similar multi keyway timing set so i can dial the cam in properly. I went for a drive today and at light throttle it was very driveable, but at 2/3s throttle it kinda "hiccupped" under load. I reckon it wants more fuel so I went on Ebay and bought a chip off mvititurbo that claims to give 20 bhp by richening the fuel mixture. Real cheap(17.95 incl postage) I hope it works , I hope it bloody shows up! And yeah I'm keen to go to the drags if possible.

Vortex-98 · 25-04-2018, 01:23 PM

The TFS double valve springs are recessed to fit gt40p heads with no machining needed...