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Q: 3,0V6 cams in 2,5V6

851 views 17 replies 8 participants last post by  Buus 
#1 ·
I want to put in some 3,0 cams in my 2,5V6 engine and have a Question or 2 for you:

The difference on cams from the standard (170bhp) and the GSI (195bhp) Vectra is only the inlet cam... Correct?

And the GSI inlet cams is the same as the 3,0 inlet cam, why then change the outlet cam to the 3,0 type?

Do I only need to find 2 inlet cams from a 3,0 or all 4.

What have you done to your V6 for more power.
 
#2 ·
Yes, only the inlet cam is different.
I had all 4 fitted but there is no diference in the exhaust cam (at the time, there were a few differing opinions so I took the safe option ;) )

My Cav V6 has....
3.0 Omega cams
Scorpion GrpA exhaust with no middle box
ITG panel filter (I run a cone in the winter)
Airbox is fed by an inlet just below the bumper.

If I can get a decent system sorted I will run the cone throughout the year.... it's that hot air that's the problem though..


On the rollers earlier in the year it put out 204bhp..
 
#3 ·
torque curve between 3lt and 2.5 cams

I must say, I do fancy getting my hands on a set of 3.0lt inlets.....

204 bhp is very very appealing :)


I do have one question though, does the 2.5 cams profile mean there is more torque lower down in the rev range? Does getting 3.0lt ones push the majority of the power 4.5k+ ?

The reason I ask is I have an F25 (I think) box, basically really tall gearing, I don't really want to reduce its 55 - 85 pull.

What difference did you notice on a "before" and "after" the CAM change?
 
#5 · (Edited)
Just to confuse the issue I thought that the 2.5 Vectra GSI just had the 3.0 exhaust cams and the 2.6 Vectra GSI had all 4 cams:confused:

The 2.6 GSI had lower power, but much higher torque over a wider range.

Found these figures from elsewhere:

The 2.6 Gsi however produces less bhp than the 2.5 at 180bhp compared to 195 on the Gsi but produces more torque 202lb-ft as opposed to the 2.5s 193.1lb-ft.

I have done a few things to mine to get a bit more power out of it:

K&N panel filter
Single cold air feed
Enlarged throttle body
Gas flowed plenum chamber
And now that I have a new job sorted out I will be getting myself a new catback exhaust system, probably a Mongoose, just to be different to most other Vectra owners.
 
#9 ·
V6 Pete said:
But has it lost low end torque?
Nope.... still got a huge grin from 3.5k... the torque curve hasn't been shifted up the rev range at all..
There is no downside, it's all benefits...(well, as long as you don't count excessive fuel consumption cause by clicking it into Sports mode and utilising the kickdown at every available opportunity)

Adam_Davis said:
Blimey!

That sounds like a very good deal to me.

Care to expand on this deal.....
Well... The Scorpion came to me for £75 2nd hand..
Bought a complete pair of 3.0 heads for £100, nicked the cams and then sold the heads for £100 :D
Got the cams fitted at the same time as I had the belt done so no extra cost there..

I don't count the air filter in the cost as that is a consumable ;)
 
#12 ·
:D
Nowthen!

Ive got a 2.6 GSi, 178bhp 202 ft.lb as standard, remapped ( HIGHLY RECOMMENDED!) to 191bhp 221ft/lb, with a pipercross Viper ? Dunno what that added (much better)... Any ideas?

But, as for the 2.5, the early GSi's had just the inlet cams changed, on later 2.5 GSi's they changed all four as this helped the torque curve, as the old ones used to bog down really badly, ie pulling out of juctions slowly in 2nd was dangerous...

First and most benificial mod is to sort the breathing out, filter and exhaust can see the SRi/cd/cdx/gls spec engine putting out high 180's bhp after that cams, headwork etc. BUT most importantly in terms of power delivery and "feel" is the flywheel, get a lightened one in, can save between 1.0 and 0.5 sec to 60 and instant response, if you into the traffic light grand prix?! lol

:p
 
#13 ·
Roadrunner said:
:D
Nowthen!

Ive got a 2.6 GSi, 178bhp 202 ft.lb as standard, remapped ( HIGHLY RECOMMENDED!) to 191bhp 221ft/lb, with a pipercross Viper ? Dunno what that added (much better)... Any ideas?

But, as for the 2.5, the early GSi's had just the inlet cams changed, on later 2.5 GSi's they changed all four as this helped the torque curve, as the old ones used to bog down really badly, ie pulling out of juctions slowly in 2nd was dangerous...

First and most benificial mod is to sort the breathing out, filter and exhaust can see the SRi/cd/cdx/gls spec engine putting out high 180's bhp after that cams, headwork etc. BUT most importantly in terms of power delivery and "feel" is the flywheel, get a lightened one in, can save between 1.0 and 0.5 sec to 60 and instant response, if you into the traffic light grand prix?! lol

:p
Glad to see you're still smiling John!

I have just ordered my Mongoose catback exhaust and will hopefully get it fitted next week and then I would love to get it on a rolling road to see how much it is pushing out:D
 
#15 ·
I really don't know which is best.

Both of them have a really good reputation, but the Scorpion will be loud by all accounts.

I opted for the Mongoose in the end because my car is a pre-facelift and hence it does not the rear skirt to cover the bulbous Magnex backbox.

Magnex also have a far better build-quality reputation in comparison to Scorpion.
 
#18 ·
Bindegal:

I haven't got my Calibra V6 anymore...

Now its a Vectra V6....

I'm want to try fitting the 3,0 cams into the Vectra at first, then see what more to do...

I have had my eye on the supercharger kit from Regal, but it is very expensive and I can't find out if regal lower the compression or the charger just runs with low pressure... 0,25 - 0,30 bar perhaps...
 
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