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Post by myothercarsa2cv on Feb 10, 2017 11:57:31 GMT
Boost at idle?! What pulley combo do you have?
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Post by AutotestAddict on Feb 10, 2017 12:55:43 GMT
I can't remember the ratios off the top of my head, but its the smallest available nose pulley coupled with a custom big crank pulley. I mean I always knew it was a stupid idea, but I thought lowering the rev limiter would mean I didn't ruin anything. I have spent many hours tracking down the slightest leaks so that I can properly starve the charger of air at idle and reduce the whine as much as is possible.
In my defence, the low down instant torque is intoxicating, if a little 'exciting' in the wet, and I've done FTD at the last 4 'solos I've attended (cheating!). If I could have that without the headache inducing noise I'd be very happy.
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Post by AutotestAddict on Feb 10, 2017 13:10:27 GMT
Ok so plan - Spend the summer NA with a remap Full 'charger rebuild kit from the 'bay, new bearings/seals/oil Have current restrictive intake milled out to maximise airflow/minimise heat Cobble together some sort of air box to minimise induction noise (could I use the standard airbox?) and then, if I can bring myself to do it... Swap large crank pulley with smaller one for less boost, fewer lols, and boost coming in further up the rev range....
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Post by Woofwoof on Feb 10, 2017 18:44:02 GMT
Add to your list:
Find out what the S/C max rev's are and then do your sums to make sure you run suitable pulleys. Fit a boost gauge. Have the Air/Fuel ratio checked. Only fit an enclosed air box after the S/C pulley ratios are sorted.
What S/C are you using?
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Post by myothercarsa2cv on Feb 10, 2017 18:44:34 GMT
Ok so pulleys... from memory, the mini crank pulley is 140mm and the nose pulley 65.5mm, giving a ratio of 2.14. The maximum the mini guys recommend going up to is a 20% reduction, or 52.5mm nose pulley and a ratio of 2.67.
With a 150mm pulley (standard overlay size), and a 17% reduction (54.5mm and a common reduction for MX5s) you're running a ratio of 2.75, which is higher than the most extreme minis and well over the recommended RPM limit of the charger (6,500 x 2.75 = 17,875 charger RPM). If you up the pulley size to a 60mm (2.5 ratio) you might even find a few horses because of the reduction in heat generation. You could probably go as small as 58mm on the nose but any more and you're in to crazy charger RPM territory again.
Before you do anything else, tap up Freaky Parts for a larger pulley and get your tune adjusted and see how that goes.
Re airbox, Salon Motorsport do a neat one for charged 5s.
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Post by Woofwoof on Feb 10, 2017 18:51:38 GMT
Nearly 18,000 rpm! Iirc, the M45 max'ed @ 14,000.
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Post by AutotestAddict on Feb 10, 2017 19:10:14 GMT
I'm sure I read that 19,400 was the max for an Eaton 45. I guess that explains my problems then. It wasn't like I drove it gently on solo's either.
I guess I am stuck then with replacing the nose pulley with a standard one, to suit my 150mm crank pulley. This is a job I really wanted to avoid!
I reverted to standard intake this afternoon and went for a jaunt. It's depressingly slow but it's really nice to be able to hear the exhaust again.
Anyone want to swap a standard pulley for a little one?
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Post by Rickster on Feb 11, 2017 10:46:52 GMT
Or like the thread on here somewhere - drop a nice 3l v6 jag engine in! A long term aspiration, but having done the sums, approximately £8k for the completed rocketeer kit is *way* out of reach for the foreseeable. Im following this thread with interest mighty5s.com/thread/1495/v6-mx-5-mk2
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Post by myothercarsa2cv on Feb 11, 2017 11:45:40 GMT
I guess I am stuck then with replacing the nose pulley with a standard one, to suit my 150mm crank pulley. This is a job I really wanted to avoid! I reverted to standard intake this afternoon and went for a jaunt. It's depressingly slow but it's really nice to be able to hear the exhaust again. What nose pulley do you have? KAVS? If so just ask Stewart at Freaky Parts for a 60mm, he made one for me at considerably less cost than KAVS. If you're not too far from me (NW Kent) borrow my 60mm for a jaunt and see if that makes a difference. Changing these is so easy. If it's a press on... ugh. Have you tried the standard intake on the supercharger setup?
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Post by AutotestAddict on Feb 11, 2017 15:45:12 GMT
I guess I am stuck then with replacing the nose pulley with a standard one, to suit my 150mm crank pulley. This is a job I really wanted to avoid! I reverted to standard intake this afternoon and went for a jaunt. It's depressingly slow but it's really nice to be able to hear the exhaust again. What nose pulley do you have? KAVS? If so just ask Stewart at Freaky Parts for a 60mm, he made one for me at considerably less cost than KAVS. If you're not too far from me (NW Kent) borrow my 60mm for a jaunt and see if that makes a difference. Changing these is so easy. If it's a press on... ugh. Have you tried the standard intake on the supercharger setup? Thanks, I believe it is a press on, but having done a bit of research I am now sending the charger off to be reconned rather than doing it myself as apparently getting at the bearings is not a job for a monkey with a lump hammer. I'm sure they will be able to swap the nose pulley for me at the same time. I've dropped Mr Freaky a message. Having driven the thing 100 miles today, which is more than in the last 6 months I'll wager, I think I can live with it NA for a bit. Its such a huge difference, but not necessarily a bad one. Before it was 4th and 5th everywhere, now its 1st, 2nd, 3rd only, and 5th for cruising. Not fast, but then do cars really need to be to be fun? I can drive it hard everywhere now, which is properly fun. I haven't got a headache and I didn't use any fuel so its not all bad. I need to get used to using gears and carrying speed though, I've got very lazy! This might now be a longer term thing as I *may* have been tempted into a kit car again. The charger would then go on once the engine was in the kit car, rather than sorting piping and airbox and what have you in the '5 bay. I could definitely live with a sensible ratio if the chassis lost 3-400kgs.
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