How much does it take to break a 3.3 barrel?
- Thread starter sjd
- Start date
What do they give as a running in period when the car is new? I'd have thought sticking to that would be a safe option, followed by a full oil change and flush.
Good to hear it's almost done Simon, you still sure you've got enough fuel with the CIS for that 3.4ltr motor? I know BW's dyno doesn't log AFR, besides the engine isn't under the same load on any chassis dyno as it is on the road.
Would be good to see the beast when it's done, you still up for a trip to Aylesbury for a run on the old GForce rollers, same issues as with any chassis dyno but at least it logs AFR on a graph for you. I've done some tweaking with mine too, would be good to put them side by side, maybe we can arrange a group thing, I know a few that would be interested, might be fun?
Good to hear it's almost done Simon, you still sure you've got enough fuel with the CIS for that 3.4ltr motor? I know BW's dyno doesn't log AFR, besides the engine isn't under the same load on any chassis dyno as it is on the road.
Would be good to see the beast when it's done, you still up for a trip to Aylesbury for a run on the old GForce rollers, same issues as with any chassis dyno but at least it logs AFR on a graph for you. I've done some tweaking with mine too, would be good to put them side by side, maybe we can arrange a group thing, I know a few that would be interested, might be fun?
To run the engine in Bob has suggested we put 500miles on the pistons/barrels initially. I will flush the oil when I get it back at 650miles and then put on at least another 500 before serious use.
I know there are differing views on fueling. I have made my own observations and have been guided by Bob, who has served me well. We already have the Andial fuel enrichment kit which has been set at position 3 (out of 5) and when turned up to 5 the car runs far too rich and covers the back of the bumper with black soot - I know this as the dial runs anti-clockwise and I had it set on 5 for a short while thinking I had it turned off!
Bob is also to reduce the fuel pressure by modifying the pressure regulator which causes the car to run richer. He is confident we can feed the fuel in - the mechanical CIS was capable of feeding the 934...just not as controlled as EFI systems so I am sure it will run rich at some points. Undoubtedly EFI will produce more power, but I like the "old fashioned engineering" which is why I bought a 1980's car in the first place (albeit 11 years ago!).
I would be interested to do a back to back session with some like minded 930's - that way you get a relative gauge as well an absolute number. G-Force were happy with AFR when we did the 473bhp run, so it will be interesting to see what difference the latest mods make. The car should be back for May, so please suggest some dates and let's arrange it.
regards Simon
I know there are differing views on fueling. I have made my own observations and have been guided by Bob, who has served me well. We already have the Andial fuel enrichment kit which has been set at position 3 (out of 5) and when turned up to 5 the car runs far too rich and covers the back of the bumper with black soot - I know this as the dial runs anti-clockwise and I had it set on 5 for a short while thinking I had it turned off!
Bob is also to reduce the fuel pressure by modifying the pressure regulator which causes the car to run richer. He is confident we can feed the fuel in - the mechanical CIS was capable of feeding the 934...just not as controlled as EFI systems so I am sure it will run rich at some points. Undoubtedly EFI will produce more power, but I like the "old fashioned engineering" which is why I bought a 1980's car in the first place (albeit 11 years ago!).
I would be interested to do a back to back session with some like minded 930's - that way you get a relative gauge as well an absolute number. G-Force were happy with AFR when we did the 473bhp run, so it will be interesting to see what difference the latest mods make. The car should be back for May, so please suggest some dates and let's arrange it.
regards Simon
Not sure when my car will be ready, should only be a week or two, i'm up for whatever dates. Will be good to get a few of us together, there's a new (ish) chap with a BTR that's up for it, i'm sure i can get a couple of 965 men on board too.
I think you'd be better off with a better set up than the Andial for your fuel, there is better management out there for CIS, you can make your WUR adjustable and with the addition of a ignition controlled solenoid you can delay enrichment until it's needed. The Andial enrichment is a bit archaic, and i wouldn't be happy with a fresh engine being managed by it for "on boost" enrichment.
I know you know your onions Simon but you may want to think about other alternatives. BW didn't get on well with 911Addicts adjustable WUR, but that doesn't mean it's the wrong set up, it just means that he doesn't know how to set it up yet. I guarantee once he does he'd swear by it. Just food for thought.
I'll ask around about who's up for a dyno day and get back to you, congrats on getting near the end with your engine, I know only too well what it feels like to go through the arse ache of stripping and rebuilding, look forward to meeting up
I think you'd be better off with a better set up than the Andial for your fuel, there is better management out there for CIS, you can make your WUR adjustable and with the addition of a ignition controlled solenoid you can delay enrichment until it's needed. The Andial enrichment is a bit archaic, and i wouldn't be happy with a fresh engine being managed by it for "on boost" enrichment.
I know you know your onions Simon but you may want to think about other alternatives. BW didn't get on well with 911Addicts adjustable WUR, but that doesn't mean it's the wrong set up, it just means that he doesn't know how to set it up yet. I guarantee once he does he'd swear by it. Just food for thought.
I'll ask around about who's up for a dyno day and get back to you, congrats on getting near the end with your engine, I know only too well what it feels like to go through the arse ache of stripping and rebuilding, look forward to meeting up
Tom - Not sure why your car feels "slow" - something is clearly still not right. Please let us know if there is anything we can do to help.
If you could make it to the rolling road session, perhaps we could take a look and also establish whether the car is slow, or you are just looking for 1000bhp!!
cheers Simon
If you could make it to the rolling road session, perhaps we could take a look and also establish whether the car is slow, or you are just looking for 1000bhp!!
cheers Simon
Jon - I will check the diary and give G-Force a call. Clearly if there is a bunch of us they will need advance warning and time to get all the cars through. I will see if this can be done on a Sat morning or whether it will need to be a weekday (I see there is a bank holiday at the back end of May, which could work?). Let me know when you have an idea of interested numbers.
G-Force have confirmed availability for Saturday 24th May. The cost is on a sliding scale. 1-5 cars is £60, 6-10 cars £50, 11-15 cars £45 and £40 up to 20 cars. The organiser goes "Free" so this can be allocated to overall cost.
50% deposit due 2 weeks before and balance on the day.
Interested? - I will make new post to see if wider group would be up for it.
50% deposit due 2 weeks before and balance on the day.
Interested? - I will make new post to see if wider group would be up for it.
ORIGINAL: sjd
Check these out - the result of a track day in September. Was running about 475bhp. RUF thought the 3.3 barrel may be a weak point... looks as though they were right! Engine since rebuilt with 98mm barrels and 7.5CR mahle pistons - now run-in and with Bob Watson to tune.
The difference is that they are fully finned.
George Elliott
New member
Simon,
Millions of tonnes of pressure at 20 deg C I guess. Some genius could calculate it exactly perhaps.
In the application where its producing 475bhp with correct A/F Ratio it should not fail, but from your excellent images, there is an area on the outer surface near the top, which looks to have been exposed to intense localised heating. The crack perhaps originated from that. I vaguely recall reading that an exhaust can fail and concentrate heat from that failure in a way that could cause this.
Better luck in future
George
944t
964
Millions of tonnes of pressure at 20 deg C I guess. Some genius could calculate it exactly perhaps.
In the application where its producing 475bhp with correct A/F Ratio it should not fail, but from your excellent images, there is an area on the outer surface near the top, which looks to have been exposed to intense localised heating. The crack perhaps originated from that. I vaguely recall reading that an exhaust can fail and concentrate heat from that failure in a way that could cause this.
Better luck in future
George
944t
964
I had wondered if the head stud had touched and scored the outer face of the barrel to produce a weak point. Fact is that it is the cylinder further away from the cooling fan and on the lower surface that failed ...i.e. where is will get the least cooling....
The car had been fine with 4 speed box with low ratio ring and pinion for general road use - the failure occured after I had fitted 5 speed box and was able to hold revs for longer and hit limiter in 5th....at this point the engine will have been producing maximum heat!
...gave me an excuse to upgrade further so let's hope this time it survives longer...
The car had been fine with 4 speed box with low ratio ring and pinion for general road use - the failure occured after I had fitted 5 speed box and was able to hold revs for longer and hit limiter in 5th....at this point the engine will have been producing maximum heat!
...gave me an excuse to upgrade further so let's hope this time it survives longer...
It should help.
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