Why 4 fuel injectors vs 6 on the '09's?
01-05-2009, 04:56 PM
#51
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i have heard a 2nd hand report of an engine dyno (not chassis- engine) which points to higher hp in the series II but i have not seen the results myself. the report came from a very reliable source which i would never doubt.
01-05-2009, 06:15 PM
#53
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Have you seen an oil dribbler??? There was probably more cost in the machine work to the housing than the actual dribbler itself. You could use a sprinkler head and have more engineering and cost that the standard oil nozzle.
But that is besides the point. I am not saying that everything on the S2 is cheaper. There are definite improvements. I am merely suggesting that on of the possible reasons that there are not 6 injectors is cost. As a cost cutting measure there are only 4.
Until someone aftermarket builds up a motor and starts playing and see's if 3 per rotor is better than 2 per rotor, we will never know because everything a manufacture does is a compromise between the bean counters and engineers.
US models had the LED rear side markers for the whole production so far.
Which again points to cost... say they decided that EMOP's are better and want to use them, but they can't exceed a price point... can't spend the money to use the 6... then you use 4 and make due and cover it up with software and gearing.
<edit> have we seen consistent dyno runs yet on the S2? Is there any power increase? I personally suspect their will be a loss, but then I have not seen dyno runs on the updated motor yet <end edit>
But that is besides the point. I am not saying that everything on the S2 is cheaper. There are definite improvements. I am merely suggesting that on of the possible reasons that there are not 6 injectors is cost. As a cost cutting measure there are only 4.
Until someone aftermarket builds up a motor and starts playing and see's if 3 per rotor is better than 2 per rotor, we will never know because everything a manufacture does is a compromise between the bean counters and engineers.
US models had the LED rear side markers for the whole production so far.
Which again points to cost... say they decided that EMOP's are better and want to use them, but they can't exceed a price point... can't spend the money to use the 6... then you use 4 and make due and cover it up with software and gearing.
<edit> have we seen consistent dyno runs yet on the S2? Is there any power increase? I personally suspect their will be a loss, but then I have not seen dyno runs on the updated motor yet <end edit>
01-05-2009, 07:23 PM
#55
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its probably just a realization that they never made even close to the 270hp they were originally aiming for.... and the extra injectors were never remotely needed
and i believe so far all the series II cars are putting up slower times so far in the rags
and i believe so far all the series II cars are putting up slower times so far in the rags
01-05-2009, 08:12 PM
#56
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There has been plenty of evidence by RENESIS re-builders to show that the Apex Seals have been wanting for lubrication in the centre (middle) of the seal.
I don't think Mazda Engineers have added a middle one for no reason or to cut costs. BTW the new 8 is slightly heavier, must be the cost cutting.
Where is this "US rear LED" side marker you talk of, I can't see it, this pic is of a 2008 US RX-8.
Oil Feeder Nozzles..
I don't think Mazda Engineers have added a middle one for no reason or to cut costs. BTW the new 8 is slightly heavier, must be the cost cutting.
Where is this "US rear LED" side marker you talk of, I can't see it, this pic is of a 2008 US RX-8.
Oil Feeder Nozzles..
Last edited by ASH8; 01-05-2009 at 08:27 PM.
01-05-2009, 08:25 PM
#57
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The new RX-8 was tested with a Series I at a well know Touring Car track (with many corners, dog legs and a straight) in Australia and the new RX-8 was actually quicker on a timed lap when compared to the Series I.
I put that down to changed Diff ratio's, and perhaps the improved and latest RE050A tyres (tires), changed rear suspension geometry. Maybe new gearbox. I really don't think the engine puts out more HP though.
Last edited by ASH8; 01-05-2009 at 08:29 PM.
01-05-2009, 11:36 PM
#58
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The new ratios just prove what I've been saying for a long time. There is no point in going more more more when it comes to gearing. 4.77 is a joke pure and simple. A worthless cruel joke. The 4:44 was way more than enough and in my personal opinion already too aggressive for the stock transmission ratios. I personally feel the RX-8 should have always come with a 4:10 rear end. Even the S1's shift way too many times.
01-06-2009, 12:46 AM
#59
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There has been plenty of evidence by RENESIS re-builders to show that the Apex Seals have been wanting for lubrication in the centre (middle) of the seal.
I don't think Mazda Engineers have added a middle one for no reason or to cut costs. BTW the new 8 is slightly heavier, must be the cost cutting.
I don't think Mazda Engineers have added a middle one for no reason or to cut costs. BTW the new 8 is slightly heavier, must be the cost cutting.
#1 We are talking about 4 Fuel injectors vs 6 fuel injectors.
But since you seem hung up on the cost issue (and I apologize to the OP for this de-rail of what you intended the thread direction to go):
#2 I guess you have missed completely that I have said there are improvements. The third oil injector is clearly one of them... but anyone that has even seen a oil injector can see it is nothing more than an oil dribbler. You are not injecting oil like you inject fuel. You are dribbling it in. This is proved by the test you, yourself posted that uses fairly low pressure water to confirm operation. But again... a second MOP and machining the housing to accept another oil dribbler probably cost more than the dribbler itself and far less than a additional fuel injector. Either way this addition can only be considered a running fix/change for a latent design flaw. Perhaps it could be said that the removal of the extra fuel injector could be pointed to offsetting the cost of adding an extra oil injector per rotor.
#3 heavier is not better... but the extra weight comes from the rear end structure re-design so that it will pass US federal rear impact safety standards for the 2011 model year (which buys Mazda not having to release the S3 RX-8 until 2012 or later). Again this follows the S5 RX-7 which also grew heavier (by around 150 lbs) due to safety requirements needed to sell the car in North America or the 2010 Mazda 3 weight gains and rear structure design for the same reason.
#4 The LED rear side markers on the 2004-2008 US models can easily be seen at night, and in the day picture you posted can be seen in the silver bars in the tail light assembly where the rear side red reflector is located.
So ash8 if you wish to discuss the merits or lack of merits about the '09 and '10 models vs the '03-'08 models, we can start another thread as this one has been derailed enough off of why there are 4 injectors instead of 6.
Originally Posted by zoom44
i have heard a 2nd hand report of an engine dyno (not chassis- engine) which points to higher hp in the series II but i have not seen the results myself. the report came from a very reliable source which i would never doubt.
01-06-2009, 04:47 AM
#60
Super Moderator
Mate, you are the one going on about cost, YOU brought it UP!
Yes, it was my bad, I got mixed up, you talking about oil nozzles then Injectors in same post.., I put it to my Old age! HA!
Of course I know the difference mate!
Back on topic....
BTW, I have been told by my local Mazda PM, that the rear structural changes for US have not occured?
The strong rumor this side of the world is the current 8 will be finished here in 3 years, and IF, repeat IF there is a new one (S3) it won't be coming to Australia....don't know about the US.
Personally doesn't make sense to me, I heard it from a very good source, and I said at the time I don't believe it.
Sorry OP, back on topic.
Yes, it was my bad, I got mixed up, you talking about oil nozzles then Injectors in same post.., I put it to my Old age! HA!
Of course I know the difference mate!
Back on topic....
BTW, I have been told by my local Mazda PM, that the rear structural changes for US have not occured?
The strong rumor this side of the world is the current 8 will be finished here in 3 years, and IF, repeat IF there is a new one (S3) it won't be coming to Australia....don't know about the US.
Personally doesn't make sense to me, I heard it from a very good source, and I said at the time I don't believe it.
Sorry OP, back on topic.
Last edited by ASH8; 01-06-2009 at 04:59 AM.
01-06-2009, 06:44 AM
#61
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But why do you suspect less power?
01-06-2009, 09:56 AM
#62
Is it possible that the 6 injectors of the -2008 models exacerbated the injected oil film dilution issue that the additional oil injection suggests Mazda was keen to correct? Specifically, could the secondary and auxiliary injection streams been colliding in such a way as to cause fuel condensation in the -2008 models that would attack the injected oil film? I'm sorry if the answer is obvious to those in the know (which I definitely am not); but absent a good argument in favour of 4 injectors in lieu of 6, I figure that any hypothesis should be presented for discussion.
01-06-2009, 10:03 AM
#63
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Sorry I am skeptical myself on that. The fact you believe says a lot and I would generally accept that myself from your opinion, but the track testing that the mags seem to be doing are not indicating any improvements... so again it comes down to once someone has some real dyno tests posted, then we can go that direction.
no need to say sorry. i purposely put some hedge in that post because i havent seen the numbers myself and can only be vague when talking about it.
01-06-2009, 10:22 AM
#64
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There has been plenty of evidence by RENESIS re-builders to show that the Apex Seals have been wanting for lubrication in the centre (middle) of the seal.
I don't think Mazda Engineers have added a middle one for no reason or to cut costs.
I don't think Mazda Engineers have added a middle one for no reason or to cut costs.
Not to argue, but odds are, it IS being done for cost, too... Adding a middle injector most likely takes care of the problem noticed by the aftermarket... That's a helluva' lot cheaper for them to do than replacing an engine under warranty...
Let's not be too naive to think design revisions are done solely due to an engineering standpoint...MOST decisions in the corporate & manufacturing world, regardless of what they are come down to benefit/cost ratios. Rest assured, an auto manufacturer isn't going to change something that solely effects reliability on a niche market vehicle... They're changing it because the benefit/cost analysis told them it's cheaper to add another one than to replace engines under warranty, and the warranty claims killed their vehicle sales goals originally, so they want to get back the image that they are reliable.
Personally, I think the rotary is VERY reliable, but my opinion doesn't matter.
01-12-2009, 03:42 AM
#73
Super Moderator
The new ratios just prove what I've been saying for a long time. There is no point in going more more more when it comes to gearing. 4.77 is a joke pure and simple. A worthless cruel joke. The 4:44 was way more than enough and in my personal opinion already too aggressive for the stock transmission ratios. I personally feel the RX-8 should have always come with a 4:10 rear end. Even the S1's shift way too many times.
I love my car, but I am constantly changing gear!!..
In fact I am going to complain and TRY and get the Series I (Lower Ratio Diff),
I am going to see if they will replace in under warranty...GOOD Luck you say...
Really, I am not impressed at all...
In 4th gear at 3000 RPM I am doing 36 MPH or 60 KMH! which is our suburban speed limit, so to lower revs I have to change to 5TH!, then to prevent her from laboring if I bring up the revs I am speeding!
We have speed cameras everywhere!
Sorry, but it is Bullshit!
Last edited by ASH8; 01-12-2009 at 03:49 AM.
01-12-2009, 07:05 AM
#74
Is it possible that the switch to 4 injectors was intended as a reliability improvement by ensuring that all the injectors see duty cycles on a regular basis, unlike the 6 injector setup where the auxiliary might not see use if someone was new to the rotary and neglected to bring the revs above 6500?
