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RX8 Yellow denso 195500-4450 425cc pnp review

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Old 07-11-2012, 11:45 PM
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Default RX8 Yellow denso 195500-4450 425cc pnp review

Sorry for the long title but I want peeps to be able to find this. I had rx7 550s and was tired of trying to get them to drive/idle like stock, so I started to look into other injectors. SO
More recently peeps have been running these rx8 injectors and I found fitment information but almost nothing on how people like these injectors Also no reviews of how they are comparatively. So here is one.

These are good injectors. Factory stuff, so they ought to be reliable and pretty close flow-wise. They are a much better design than the rx7, supra, and stock miata injectors (better atomization at lower fuel pressure and lower dead time)
And of course completely plug and play (uses stock miata inj clips, exact same length as stock miata inj).

I'm back to a smooth idle in the 14's and they drive real nice too. Mainly, if you're looking around for injectors and are on a stock bottom end, these ought to fit the bill perfectly.

Here is how I'm running them:
MS2 in semi sequential
.86 deadtime @13.2v
*EDIT*
After some trial and error, I got them to idle/drive better using these settings:
1.00 deadtime @ 13.2
batt correction .07
req. fuel 12 (puts idle in the 20's)

Feel free to post opinions ect.

and here are some rx8 inj related threads I ran across
https://www.miataturbo.net/ecus-tuni...jectors-58729/

https://www.miataturbo.net/diy-turbo...?t-56689.html=

http://www.msextra.com/forums/viewto...41357&start=20

Last edited by Jpopsbronco; 07-13-2012 at 08:37 PM.
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Old 07-15-2012, 10:23 PM
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what injector dead time did you use with your rx7's?
I have no issue idling at stoich on batch fire with my 460cc
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Old 07-15-2012, 11:45 PM
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Could you upload a log of just a 5-10min drive about town ( low load situations mostly ) if you get time. After my thead HERE ive been thinking about getting some of the rx8 injectors to try. Perhaps a before and after would be great if u dont mind.

Cheers
Scott
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Old 10-29-2012, 12:22 AM
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Originally Posted by Oni
Could you upload a log of just a 5-10min drive about town ( low load situations mostly ) if you get time. After my thead HERE ive been thinking about getting some of the rx8 injectors to try. Perhaps a before and after would be great if u dont mind.

Cheers
Scott
Sorry I never read this till now. I posted in your other thread though. To answer your question, i don't have a log but once I got my mat correction dialed in the afrs vary by like .3ish at idle.


As far as a general update:
I liked the rx8's and even noticed my mileage go up about 2 mpg with them vs rx7. I think for the $ you can't beat em for 250hp and less. My car is and was a daily driver so I had to put up with these otw to work every day, and they worked great. Plans changed though and I got id725's (moar b@@st). A good general rule of thumb for injectors IMO is you get what you pay for.

In terms of idle quality, here is my list(based on MY personal experience):
-stock brown tops/ id725's are the best. Both these idled like the car did on the factory computer (perfectly)
-rx8's. runner up. bang for buck can't beat em.
-rx7 550's. fine if you're going to idle at 1000rpm or **** afrs @750rpm
.some people seem to get these to work... I wasn't one of them
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Old 10-29-2012, 01:17 AM
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I don't know how many times I need to say this, but I'll say it once again. The RX-8 425's are bosch type, which is the same as the factory 99-up injectors for the miata. The atomization is better than the older (rx-7) pintle type injectors. I remember when the rx7 460's and 550's were the way to go. Hell I even had a set of the 460's. Now, since they're 20 years + old, I wouldn't pay more than $80 for a brand new set of them. The RX-8 bosch type is the way to go, and the only way anybody should go if buying a budget injector.
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Old 10-29-2012, 01:52 AM
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We like these too.

Attached Thumbnails RX8 Yellow denso 195500-4450 425cc pnp review-195500_4450_miata_rx8.jpg  
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Old 10-29-2012, 02:29 PM
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This came at a perfect time! I shall be buying some soon. I like good plug and pray hardware.
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Old 10-30-2012, 12:09 AM
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I've been running the yellow top RX-8's for the past month or so.
I'd been using 0.8 dead time, 0.100 voltage correction, 8.0 req fuel. With these settings I noticed a very slight bit of chassis shake at idle from the engine not idling 100% smoothly. AFR held right around 14.7 +- 0.2 or so. 850 rpm w/o AC 1k with.

I wrote it off as just part of having larger injectors, but today decided to change the settings a little closer to Jpopsbronco's suggested settings with:
0.9 dead time, 0.08 voltage correction, 8.0 req fuel, and the little bit of shakiness is gone. Driving seems about the same (as I figured it probably would be), but the idle is ever so slightly smoother than before.

One slight issue I've noticed is the MS2 seems to have a harder time "catching" the idle when the A/C is initially switched on (rpms dip much lower when A/C is first turned on compared to old settings). I'm going to try 0.120 voltage correction tomorrow, and see if that helps/hinders the issue.

Just wanted to share my results incase it helps anyone else.

Last edited by SJP0tato; 10-30-2012 at 12:24 AM.
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Old 09-01-2019, 10:03 PM
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Does anyone have the values for the lag-time curve needed in the MS3 or similar?
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