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[2woody]

I recently took 3.0 cams out of my 2.6 and gained 4 horsepower.

thinking standard fueling not up to changed requirements of 2.5 with bigger cams

Interesting...

I understood the fuel system is the same between 2.6 and 3.2  - same fuel pressure and injector flow rate so it should be up to delivering the same fuel.

2.5 and 3.0 apparently have the same map in the ECU, not sure if that holds for 2.6/3.2 though. :-/

I don't suppose you have before & after dyno plots? Might give some clues as to what was going on?

Kevin

I think it's more the "shape" of the fuel map, rather than any amounts or anything like that.

I could just about see the 2.5 / 3.0 argument, whereas the higher fuel requirement is going to be a higher requirement over the whole engine speed range, but substituting 3.0 cams will extend the fuelling disproportionately higher up.

from memory, the Vectra 2.5 (small cams) and 2.5 (big cams) had different ECUs.

Unfortunately, I didn't get dyno plots - it was done for me as a favour - I didn't really require any info - was just trying to see how many extra ponies 3.0 cams were worth in an atherwise stock engine. (it was done at a track as part of a race series' test day)

sample engine builds on the way   

[SteveT528]

I doubt the oil cooler is going to dump a huge amount of heat into the coolant in the overall scheme of things, fitting of an external oil cooler is going to be difficult without disturbing the air flow into the main rad. anyway, so cheaper and easier just to ensure adequate radiator capacity.

I do like peoples views on this and everyone is entitled to one, and everyone has a valid point some way or another,but i can honestly say fitting an external oil cooler makes a massive difference and anyone that says it dont are wrong or havnt tried, on a standard engine it is pointless and may even cause more wear on the engine over time! on a modified engine its worth while, these x30xe engines get VERY HOT while racing or even driving hard.  having unions fitted to the original oil cooler plate is a very good mod that ive done before and also unions fitted to the rear of each head , mainly the pass side head as ive seen melted pistons on the rear!  if modifing an x30xe engine the aircon will have to be removed! this blocks airflow to the rad more than a 13 row oil cooler will ever do. so thats not an issue. as always this is my opinion and experience of tuning this engine.

[Kevin Wood]

I do like peoples views on this and everyone is entitled to one, and everyone has a valid point some way or another,but i can honestly say fitting an external oil cooler makes a massive difference and anyone that says it dont are wrong or havnt tried, on a standard engine it is pointless and may even cause more wear on the engine over time! on a modified engine its worth while, these x30xe engines get VERY HOT while racing or even driving hard.  having unions fitted to the original oil cooler plate is a very good mod that ive done before and also unions fitted to the rear of each head , mainly the pass side head as ive seen melted pistons on the rear!  if modifing an x30xe engine the aircon will have to be removed! this blocks airflow to the rad more than a 13 row oil cooler will ever do. so thats not an issue. as always this is my opinion and experience of tuning this engine.

Fair comments, and obviously if the purpose is to enhance coolant flow around the rear cylinders as above than it's a good step to take.

I was just making the point that, unless the engine has been tuned far enough, and gets driven hard enough, that the cooling mods are required, it's a pointless exercise. Oil to water heat exchangers such as the standard cooler have an important advantage that they won't overcool the oil, and  will in some instances pre-heat it, and that no potentially unreliable oil stat and associated flexible hoses, etc. are required.

Anyway, I'm sure I'm preaching to the converted.

Kevin

[Kevin Wood]

I think it's more the "shape" of the fuel map, rather than any amounts or anything like that.

I could just about see the 2.5 / 3.0 argument, whereas the higher fuel requirement is going to be a higher requirement over the whole engine speed range, but substituting 3.0 cams will extend the fuelling disproportionately higher up.

from memory, the Vectra 2.5 (small cams) and 2.5 (big cams) had different ECUs.

Unfortunately, I didn't get dyno plots - it was done for me as a favour - I didn't really require any info - was just trying to see how many extra ponies 3.0 cams were worth in an atherwise stock engine. (it was done at a track as part of a race series' test day)

sample engine builds on the way   

This is where you need to get out your wideband Lambda sensor and see what's going on.

I know other members have claimed gains from this mod on a 2.6. Not sure if any have plots to hand or have even been proven on the rollers.

Gut feeling is that the ECU is probably basing the fuel requirement 100% on the MAF reading at the top of the rev range so it should cope with a little extra power. :-/

Kevin

[Phil]

from memory, the Vectra 2.5 (small cams) and 2.5 (big cams) had different ECUs.

If you are refering to the Vectra ST200 (197bhp) and the standard GSi (170bhp iirc) then no, they had exactly the same ECU and map the ONLY change to the engine was half the cams from and X30XE engine, can't remember if it was inlet or exhaust but it was only one pair not both.

[Martin_1962]

I recently took 3.0 cams out of my 2.6 and gained 4 horsepower.

thinking standard fueling not up to changed requirements of 2.5 with bigger cams

Strange - mine is quicker