My MX5 on RS Aizawa Throttle Bodies
Discussion
I thought I'd share my MX5 with you lot.
It's an early 90s 1.6 import, rebuilt in 2005 with throttle bodies from RS Aizawa.
Running an HKS FCon II-V Pro it was mapped by Re:Worx now making 128bhp at the fly.
And some videos:
http://www.youtube.com/watch?v=6p77GKI-x80
http://www.youtube.com/watch?v=3SUuBR7wYlw
http://www.youtube.com/watch?v=WgKOW8s22Og
It's an early 90s 1.6 import, rebuilt in 2005 with throttle bodies from RS Aizawa.
Running an HKS FCon II-V Pro it was mapped by Re:Worx now making 128bhp at the fly.
And some videos:
http://www.youtube.com/watch?v=6p77GKI-x80
http://www.youtube.com/watch?v=3SUuBR7wYlw
http://www.youtube.com/watch?v=WgKOW8s22Og
NotKenBlock said:
Noob question...
How hard (read expensive) is it to switch to TBs? Also is there any real world benefit other than an awesome noise (maybe reason enough)
Not that hard really if you know what your doing with the spanners, wouldn't recommend a novice doing it. Can be expensive though, well expensive to me anyway, I'm sure some on here have it in spare change down the back of their sofas.How hard (read expensive) is it to switch to TBs? Also is there any real world benefit other than an awesome noise (maybe reason enough)
I was looking to do it on my old 405 mi16 , I think it was about £1500 for the Webber setup. Bolt on 20-30bhp they claimed, but with OP saying 128bhp obviously not the case on a 5.
attym3 said:
Not that hard really if you know what your doing with the spanners, wouldn't recommend a novice doing it. Can be expensive though, well expensive to me anyway, I'm sure some on here have it in spare change down the back of their sofas.
I was looking to do it on my old 405 mi16 , I think it was about £1500 for the Webber setup. Bolt on 20-30bhp they claimed, but with OP saying 128bhp obviously not the case on a 5.
I think it's a bit of a myth that throttle bodies add significant power, they generally just increase throttle response significantly and improve airflow slightly.I was looking to do it on my old 405 mi16 , I think it was about £1500 for the Webber setup. Bolt on 20-30bhp they claimed, but with OP saying 128bhp obviously not the case on a 5.
Oh, and apparently the HKS Silent HiPower exhaust on my car is very restrictive. Should see 135bhp with a better item, apparently.
Richyvrlimited said:
You'll need a fair amount of headwork on top to approach 100hp/litre.
Headwork should have been in the list (as that is what I do), however the stock head flows quite well.Experience with other similar specced engines shows you can get pretty close if the head is a good one from the factory, a good 1600 rover K series will give 155 with cams, TBs, ECU and decent exhaust , with headwork this can go to 180 with relatively tame cams (274 degrees, 11mm lift).
Dave
Are you playing with MX5 heads now Dave?
It would be interesting to see if it would be possible to get 100bhp per litre from a 5. I would imagine it would need raised compression on top of the other mods?
My MP62 supercharged NB was rolling road tuned recently and the tuner commented on the fact that if the head breathed better it would have produced a lot more power (214bhp/174lbft).
Would cams solve this with more lift duration or would it need significant head work/bigger valves?
It would be interesting to see if it would be possible to get 100bhp per litre from a 5. I would imagine it would need raised compression on top of the other mods?
My MP62 supercharged NB was rolling road tuned recently and the tuner commented on the fact that if the head breathed better it would have produced a lot more power (214bhp/174lbft).
Would cams solve this with more lift duration or would it need significant head work/bigger valves?
MX-5 Lazza said:
The NB head flows fine for well over 250bhp. If you have the standard exhaust then that is probably where your restrictions are. FI doesn't really need or like uprated cams - I'm sure Richy would be able to explain this better than me.
I'm running a standard manifold but Flyin Miata exhaust.I was thinking in terms of NAsp rather than supercharged for head mods etc.
MX-5 Lazza said:
The NB head flows fine for well over 250bhp. If you have the standard exhaust then that is probably where your restrictions are. FI doesn't really need or like uprated cams - I'm sure Richy would be able to explain this better than me.
I'm running a standard manifold but Flyin Miata exhaust.I was thinking in terms of NAsp rather than supercharged for head mods etc.
DVandrews said:
Headwork should have been in the list (as that is what I do), however the stock head flows quite well.
Compared to what?The stock head flows terribly compared to an era equivilant Honda engine.
That's the first time in 10+ years of owning MX5's that I've heard someone claim the Mazda engine flows well.
rdodger said:
Are you playing with MX5 heads now Dave?
It would be interesting to see if it would be possible to get 100bhp per litre from a 5. I would imagine it would need raised compression on top of the other mods?
My MP62 supercharged NB was rolling road tuned recently and the tuner commented on the fact that if the head breathed better it would have produced a lot more power (214bhp/174lbft).
Would cams solve this with more lift duration or would it need significant head work/bigger valves?
You need a well rounded set of mods to get 100BHP per litre, the best I have seen on a Rover K is around 145 per litre and it just hits the wall there. I have a number of friends, a daughter and a wife who have MX5s, two of those bought by me so I may well be having a little dabble. Wifey's is a duranail in all but name and I have already seen more than 260 from a 2 litre duranail.It would be interesting to see if it would be possible to get 100bhp per litre from a 5. I would imagine it would need raised compression on top of the other mods?
My MP62 supercharged NB was rolling road tuned recently and the tuner commented on the fact that if the head breathed better it would have produced a lot more power (214bhp/174lbft).
Would cams solve this with more lift duration or would it need significant head work/bigger valves?
Th MX5 head flows well compared to a standard K series head. It wont have the airflow of a Honda or Toyota head but the potential is there.
You can only go so far with duration when running a supercharger or turbocharger, keeping the overlap down but area under the lift curve up will give benefits, so rapid valve acceleration, highher peak lift and realtively short duration would be good for FI. For NA you will need quite a bit more duration to get the scavenging going at the right point in the rev band.
Dave
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