5L seems a bit slow.

[james1988]

Hey guys, ive had a search, but couldnt find much.

I have a VS with a 304, it has the following done:
Ford GT toploader
4.11 diff gears
acl flat top pistons, rods, race series rings and bearings
"stage 2 crane cam" - i dont know what cam it is, but it sounds only mild, to light.
and full exhaust, no cats.

ive driven my friends standard manual 5l and it is NOTICEABLY slower than his.
the car has very little pick up until about 4k then it still doesnt pull hard at all.

snap on scan tool says oxygen sensor has been playing up, so i have ordered one of them but am yet to replace it.
i changed ignition leads and plugs, but repco only had cheap crap in stock ( i am planning on getting some nice quality ones during the week)

i am planning on changing the fuel filter, oil and oil filter during the week.

but is there any other things i could give a go. compression test?
any help would be appreciated.

[Zeussy]

Compression test is where I'd start..

[someguy360]

Remember the 5L was never a really "quick" motor, I beat alot of 5l's out on the track with my mildly modded 6. Until you start doing serious work to them they are a bit slouchy.

It shouldn't be as bad as you are describing though, run a compression test

Also when you say you don't have any cats, you mean not at all? Because you might not have enough backpressure which can cause serious performance issues, I didn't have a cat on the VS for a while and then put a high flow stainless one on and it made a huge difference. From my experience engines that were designed to run on the backpressure of a catalytic converter won't run very well without one unless you do some serious tuning


also remember the engine has to be tuned if it has a new cam

[simmons001]

Remember the 5L was never a really "quick" motor, I beat alot of 5l's out on the track with my mildly modded 6. Until you start doing serious work to them they are a bit slouchy.

Yah yah. plenny torque, great motor, better down low than an LS1, but need work to be quick.

start with the basics as advised... then cam dialed in? is it a toppy cam? mismatch between cam and heads?

[james1988]

there's no cats at all, just pipe where the cats would be. i really should be putting cats on it regardless of any difference in performance.

I really know nothing of the cam thats in it, the car was bought with the engine work done.

i will do a compression test, and do oils/filters, and get some decent leads/plugs. then i might go get it tuned. atleast then i could get a power reading and see if im just going crazy.

could a tune cater for the cat-less exhaust?

[drewVHSS]

With the flow characteristics of the 308 heads and especially worse with the VN 5.0L heads combined with the valve seat angle they have. 308's/5.0's suffer from flow reversion. they rely heavilly on previous exhaust pulses in the system to help pull the next one along. Hence with vn 5.0L dont respond well to dual exhausts vs a well designed good flowing single exhaust.
If the engine doesn't breathe well enough, you'll never get the power out of it.

[Reaper]

No idea what a "stage 2" cam is but what you are describing sounds like too much cam with too little compression. I googled "stage 2 crane" and came up with a 284 which is too big for a stocker bottom end. Probably starting to get too big for flat tops (will give you around 9:1 compression) maybe a tad higher. The problem with this setup is that the cam is starting to come on song right where you run out of intake manifold.

Reaper

[dobesz]

Man u got big issues if your running 4.11 ratio, u should fry them off the line! Have a look and see what's written on the chip! As I think those cams come with chip, so would think brand name would be on it. If not and it's a standard Holden chip it's possible it's never been tuned!! Cam may be setting the knock sensor off but doubt it. When looking at chip if there is a little circuit board behind window in the blue plastic it's a knock sensor compatible chip

[Jonno]

put the cats on u joker! lol

+1 for compresson test

would be good good idea to find the spec on the cam

[james1988]

just had a look at the flange sized for the cats, and i notice that the rear muffler's internals rattle when bumped, and you can hear it at idle if your near the back of the car. could a failed muffler be part of the culprit?

[Jonno]

dunno what your exhaust systems like in the first place

but would be a good idea to go get a good system

[james1988]

pacemakers to dual 2.5 into single 3 inch, i can see the contents of the muffler by looking down the pipe with a light, its in pieces.

[james1988]

checked out the memcal doesnt say anything on it. so im assuming the car isnt tuned at all.

if there is a manifold restriction, upgrading the intake manifold would see an improvement on its own? or tune first?

[Zeussy]

Rip the exhaust off and go for a squirt, seriously, if it makes a difference there's your problem...

[kniever]

if the muffler is falling apart as said there is a good chance the exhaust is blocked which will make it sluggish

[Brett_jjj]

Id get rid of that old memcal and fit another original holden memcal that has an original holden tune that was released for your model etc. You can usually tell if a memcal is original or not by the little silvery foil sticker that covers the little round window that you can see on top of the chip, its used for erasing the eprom chip with UV light,so is usually covered by the sticker. That foil sticker I mentioned before has four letters written on it, the four letters are actually the version or the type of factory tune , once this little sticker is removed from the memcal,(so the chip can be erased and rewritten to again),then it wont stick back onto the chip again unless you use glue to glue on it, (which you wouldnt want to do). So if the sticker is there, you can be 99% sure its genuine, so has probably not been tampered with in any way. That memcal in your picture has no ID sticker over the round window on the chip, so god only knows what changes have been made to it, and by god only knows who. Theres a lot of dodgey people around who try to sell these so called tunes for heaps of cash, when they are plainly just not worth what they ask for them, "well,a lot of the time theyre not anyway", and half of the "so-called" tunes Ive opend up and looked at, or have copied from someones memcal or whatever, all have nothing that special done to them. Anyone can buy the hardware off ebay, download the programs needed, and learn about what needs to be changed etc on the memcals bin or binary file. Delcohacking is a good site to start with if you want to learn about this kind of stuff.

[Reaper]

just had a look at the flange sized for the cats, and i notice that the rear muffler's internals rattle when bumped, and you can hear it at idle if your near the back of the car. could a failed muffler be part of the culprit?

It certainly wouldn't help.

On those 5 litres 2.5", a functioning cat (hi flow is neither here nor there but if you have to buy one then get one) and some fre flow mufflers work great. Collapsed anything can't be good.

Reaper

[dobesz]

Yea a blocked muffler would not help at all, if I put my hand over my mx bikes exhaust it just about stalls. So a blocked muffler is not letting your motor get rid of gasses.
A f?cked o2 sensor will make it run rich and chew fuel.
That memcal is the correct one for hsv as u can see the knock sensor circuit board in the window. as stated has most likely been tampered with. Most "stage 2" cam packages come with cam and memcal.
But I think u should fix zorst and get it on a dyno and a proper tune, as something ain't right. Plus mail order tunes are never as good as a dyno tune. What state u from

[james1988]

Im from the NT, im hoping the very few tuners here will be happy enough to do it. i believe there are only 2 reputable ones.

im planning on just that, fix exhaust, do a service (filters, leads etc) and then tune it. hell i might even get a big intake manifold for it.

[VrWagz1]

Dont waste ur sanity. Given the work u have, its hard to diagnose over the net. Slam it on a Dyno, and have them run it till they got the solution. To me sounds like a Cam issue, like not dialled in right OR just totally miss-matched to the engine, in which case gt a new one.