ROLLING ROAD DAY - DSAUTOMOTIVES 31st MAY
- Thread starter sjd
- Start date
Simon, i'm half hoping you haven't been to the dyno yet as i need to go back too and it would be interesting to see your car run. I've finally sorted out my over-boost issue and replaced the knackerd turbos, so could do with another run on the rollers, let me know if you're up for it.
Was good to see you n Le Mans, even if it was only for two minutes, let me know either way
Was good to see you n Le Mans, even if it was only for two minutes, let me know either way
Tom, do you mean higher "lift" cams? High compression is to do with your piston's, cylinders, crank, con-rods etc and the height and length of each.
I think the stock 930 compression ratio is 7.0:1, i've heard of guys going as high as 8.0:1 on CIS but you have to be very careful about boost levels as the higher the compression the more heat and so on.
I think Simon is around 7.5:1, but he is also running high boost, probably the best compromise.
Higher compression helps with off boost throttle response and off boost power, the relationship between compression ratio and boost level will be down to how you want to use the car
I think the stock 930 compression ratio is 7.0:1, i've heard of guys going as high as 8.0:1 on CIS but you have to be very careful about boost levels as the higher the compression the more heat and so on.
I think Simon is around 7.5:1, but he is also running high boost, probably the best compromise.
Higher compression helps with off boost throttle response and off boost power, the relationship between compression ratio and boost level will be down to how you want to use the car
That would be nice to do Tom, but the cost is quite outrageous IMO unless you actually need new P's or C's...
7.0 to 7.5 is a very small difference. Same for the capacity, 3.3 to 3.4. I really don't think it's worth the cost if your parts are currently in good working order. As stated, increasing CR means you have to reduce boost pressure to keep out of detonation. Also it has been stated that if you go bigger bore you would also benefit from twin plugs...£££
7.0 to 7.5 is a very small difference. Same for the capacity, 3.3 to 3.4. I really don't think it's worth the cost if your parts are currently in good working order. As stated, increasing CR means you have to reduce boost pressure to keep out of detonation. Also it has been stated that if you go bigger bore you would also benefit from twin plugs...£££
tj930
New member
Yeah, do you think it's not worthwhile unless you're going EFi? (In which case, you might as well START - a la Johno - with a 993tt engine?)
I was actually thinking about going for a twin-plug, 3.4 litre, K27/29, modified fuel head (probably), 7.5CR, with a BlownSix full-bay intercooler.. Hoping for something not far South of 500 horses (maybe more)..
All a bit of a pipe dream, though. (No way that I could get my young Brother insured on my car with that little lot! [
])
I was actually thinking about going for a twin-plug, 3.4 litre, K27/29, modified fuel head (probably), 7.5CR, with a BlownSix full-bay intercooler.. Hoping for something not far South of 500 horses (maybe more)..
All a bit of a pipe dream, though. (No way that I could get my young Brother insured on my car with that little lot! [
])Guys - I am back. Just started 6 week break from work, so been busy lately.
Jonathan - I will email you, but I am at DSA tomorrow at 11:00. The car has now done 1500 miles so ready to run on the Dyno properly. I am going to get DSA to check timing etc.
Tom - I am running 3.4l with 7.5CR. This has helped of boost response, but unless the 3.3s are reday to be replaced I would not go to the cost. We did flame-ring the heads etc so that we can run 1.2bar. I will post the results from the run and let you know what parts I have used. Key step up for me was to replace my K27/11 with a K27/29 bolted to my direct route manifolds. This will "test" the CIS fueling and there are many lines of thought to get around this. Mine was to use an Andial fuel enrichment kit, but I know not to everybody's taste.
cheers Simon
Jonathan - I will email you, but I am at DSA tomorrow at 11:00. The car has now done 1500 miles so ready to run on the Dyno properly. I am going to get DSA to check timing etc.
Tom - I am running 3.4l with 7.5CR. This has helped of boost response, but unless the 3.3s are reday to be replaced I would not go to the cost. We did flame-ring the heads etc so that we can run 1.2bar. I will post the results from the run and let you know what parts I have used. Key step up for me was to replace my K27/11 with a K27/29 bolted to my direct route manifolds. This will "test" the CIS fueling and there are many lines of thought to get around this. Mine was to use an Andial fuel enrichment kit, but I know not to everybody's taste.
cheers Simon
tj930
New member
Sounds exactly what I'm after! Such a shame that you weren't able to bring the beasty along last time.
Using my 'Photoshop skills', I've created a little composite of the Boost v Horsepower v AFR results - any chance that you could post up one for your car? (I'd love to see what the K29 does to your powerband - "pulls to the red line", I expect!)
Hoping very soon to get one of those UTCISs fitted in conjuction with a new Boost Tee I bought (to allow me to get a bonafide 1.0Bar), so I could do with some more Dyno Time myself! (If it's in the next couple of weeks, let me know and we'll make another party of it [])
Using my 'Photoshop skills', I've created a little composite of the Boost v Horsepower v AFR results - any chance that you could post up one for your car? (I'd love to see what the K29 does to your powerband - "pulls to the red line", I expect!)
Hoping very soon to get one of those UTCISs fitted in conjuction with a new Boost Tee I bought (to allow me to get a bonafide 1.0Bar), so I could do with some more Dyno Time myself! (If it's in the next couple of weeks, let me know and we'll make another party of it [
])Well i went up and met Simon there today, was nice to meet up again. Seams we both still have some work to do, i'll let him talk about his if he wants to but mine is still running lean. I've fitted a manual boost controller to run in parallel with the N75 valve that the ECU uses to control boost. Basically what this does is allows me to cap the boost at a certain limit, anything below that boost the ECU is free to control but i can set my own limits for safety, it eliminates boost spikes basically (i've put a diagram below for anyone interested in doing the same if they are also seeing boost spikes).
I let it boost to a peak of 1.2bar and netted much the same horsepower and torque as before, i wound it down to a peak of 1.1bar and it brought me just below 500bhp and took a chunk of torque out, none of this helped the fueling, it was still WAY too lean. The injectors have the capacity for well over 500bhp so my issue is the mapping, I need to program in more fuel basically. I'll get there in the end!
Here are the diagrams for those interested
I let it boost to a peak of 1.2bar and netted much the same horsepower and torque as before, i wound it down to a peak of 1.1bar and it brought me just below 500bhp and took a chunk of torque out, none of this helped the fueling, it was still WAY too lean. The injectors have the capacity for well over 500bhp so my issue is the mapping, I need to program in more fuel basically. I'll get there in the end!
Here are the diagrams for those interested
ok, ok , ooook - Jonathan was right. The Andial does not work. Comes in at 0.8bar, runs very rich for 1000 revs and then immediately tails off so the car runs far too lean. Best we saw was 472bhp (but with dangerous fuel level). This explains why the timing had been retarted so much. We left it that way for safety.
So... I need a modified fuel head and an adjustable WUR/Fuel pressure reg to get the fuel right and then we can dial the timing back in.
Must say having driven the car home with it skirming in 2nd under boost I question my sanity for looking to 500bhp...but it must be done!
Update to follow once we get fuel sorted. And looking forward to seeing Jonathan's car running as it should be...
So... I need a modified fuel head and an adjustable WUR/Fuel pressure reg to get the fuel right and then we can dial the timing back in.
Must say having driven the car home with it skirming in 2nd under boost I question my sanity for looking to 500bhp...but it must be done!
Update to follow once we get fuel sorted. And looking forward to seeing Jonathan's car running as it should be...
Simon, why not just get the UTCIS for now and then see if you do in fact need a fuel head later on.
We all knew the Andial wasn't up to it []
We all knew the Andial wasn't up to it [
]
Simon, what do you mean by a K27/29?
Do you mean a hybrid/custom turbo made using K27 & K29 parts?
Do you mean a hybrid/custom turbo made using K27 & K29 parts?
That is what I thought, the correct term really for it is K27/K29.
Nathan, I'm struggling to see your point? Are you saying that he shouldn't call it a K27/29 but instead call it a K27/K29? If so then you really need to get out more because that is the most extreme case of nerdiness i've witnessed to date. Hopefully i've missed something and you'll put me straight?
Ooops, sorry. I was wondering if simon had a turbo that I hadn't heard of, that was all.
Actually, RUF came up with that design AFAIK so it must have been pretty good at the time.
As you may know there are K27's that do have descriptions as Simon stated and this was what I was wondering.
I do tend to pay too much attention to the details...
I definitely need to get out in to my garage more often that's for sure []
Anyone going to Silverstone Sunday?
Actually, RUF came up with that design AFAIK so it must have been pretty good at the time.
As you may know there are K27's that do have descriptions as Simon stated and this was what I was wondering.
I do tend to pay too much attention to the details...
I definitely need to get out in to my garage more often that's for sure [
]Anyone going to Silverstone Sunday?
tj930
New member
Hee hee..
Anyway, guys, I've got one of those dastardly, intermittent problems..Think it's a misfire (rather than an overboost and fuel-pump cutting).. Typically happens in 3rd and 4th gear at around 110 (but has also happened between 80 to 140); 1st and 2nd gear are fine.
Sometimes, seconds later, the thing rev's smoothly from 0-150, no problems... I don't get it... What could it be?
Since it's almost random, I'm guessing electrical (rather than boost, fueling, or timing related).. I'm going to change the plugs and see if that helps (but I don't hold out much hope).. Can you suggest any other 'basic' stuff that I should check?
I had it suggested that it could be the Earthing strap, but that looks good.. Any ideas?
Anyway, guys, I've got one of those dastardly, intermittent problems..Think it's a misfire (rather than an overboost and fuel-pump cutting).. Typically happens in 3rd and 4th gear at around 110 (but has also happened between 80 to 140); 1st and 2nd gear are fine.
Sometimes, seconds later, the thing rev's smoothly from 0-150, no problems... I don't get it... What could it be?
Since it's almost random, I'm guessing electrical (rather than boost, fueling, or timing related).. I'm going to change the plugs and see if that helps (but I don't hold out much hope).. Can you suggest any other 'basic' stuff that I should check?
I had it suggested that it could be the Earthing strap, but that looks good.. Any ideas?
Tom, it could be loads of different things, i would have thought if it's doing it under full load in the higher gears then it would be fuel related? It might be worth checking the dizzy cap and rotor though too as you never know. It's weird that it only does it between certain speeds. Does it do it between these speeds at part throttle or only at WOT?
Nathan, yes mate, get out in the garage and get the frikin car finished, otherwise i'll come round and start ebaying parts off it []
Nathan, yes mate, get out in the garage and get the frikin car finished, otherwise i'll come round and start ebaying parts off it [
]
tj930
New member
I've cleaned, sparkled and tightened all the battery connectors. Sanded them down to make sure they make a good connection. Tested last night. No, change []
Changed the distributor cap for a tighter-fitting one about 800 miles ago; changed the sparkplug leads at the rebuild, and the rotor arm soon after. I'm going to change the sparkplugs next, but I expect this not to make the slightest bit of difference. (P1ss1ng in the wind here.)
Nigel at PowerMarques suggested fitting a Lambda sensor into the exhaust - maybe this will indicate whether the engine is just running too rich/lean?
]Changed the distributor cap for a tighter-fitting one about 800 miles ago; changed the sparkplug leads at the rebuild, and the rotor arm soon after. I'm going to change the sparkplugs next, but I expect this not to make the slightest bit of difference. (P1ss1ng in the wind here.)
Nigel at PowerMarques suggested fitting a Lambda sensor into the exhaust - maybe this will indicate whether the engine is just running too rich/lean?
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