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Injector Help - M45 + E85

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Old 10-21-2014, 09:35 AM
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Default Injector Help - M45 + E85

I just need to confirm I am on the right track with the injectors. Pretty sure I'll be AOK with RX8 440cc or RX7 460cc, but I wanted to confirm before I buy.

I am currenly in the process of collecting parts for my M45 build on my 1.6. I have the JRSC M45 kit already and MS2 to run it. It will be non-intercooled and I don't want to run meth. I don't want to deal with the air volume issues of the intercooler and I don't want to add another system and tank of something to keep full with meth.

I saw this thread. It seems like E85 will give me the charge cooling I need to get back some timing and give me a couple more horses. So, I am going from very mild power to somewhat mild I guess.

Now the plan is to run the 62.5mm TDR nose pulley with E85. Based on reading the FAQ, 1.8 injectors are good up to 8-9psi on gas, but I know I need about 30% more fuel for E85. So, by my calculations, I'd need 300cc minimum sized injectors, correct? If that is the case, I plan to run some RX7 or RX8 injectors to give me some headroom should I go bigger with power later. Does this all sound about right to you guys?
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Old 10-21-2014, 11:57 AM
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Flow Calculator
Play around with it a bit.
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Old 10-21-2014, 12:07 PM
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So according to that, if I were to (optimistically) hit 170 WHP (unlikely, I know) I'd need something with a 432cc+ratting to be at 85% duty cycle. So, RX8 440s should be just fine then, right? Sorry, I am new to this and want to be sure I don't wreck anything.
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Old 10-21-2014, 12:22 PM
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Originally Posted by Adam777
So according to that, if I were to (optimistically) hit 170 WHP (unlikely, I know) I'd need something with a 432cc+ratting to be at 85% duty cycle. So, RX8 440s should be just fine then, right? Sorry, I am new to this and want to be sure I don't wreck anything.
Yeah I would doubt you would hit 170whp on you're 1.6. I would go with the 440's. I think you have enough room to spare, but you could always get an fpr to get more out of them if need be.
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Old 10-21-2014, 12:27 PM
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Any reason to go with the newer RX8s vs. the cheaper (and seemingly more common in the FS sections) RX7s?
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Old 10-21-2014, 01:04 PM
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Well from what I read and hear, the rx8 injectors have a much better spray pattern than the older style rx7s. I had some old 440 rx7 injectors and they idled fine enough for me, so I think it's just whether you care about your idle quality vs the cost difference.
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Old 10-21-2014, 01:10 PM
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Knowing idle can be tricky with superchargers, I'll just go with RX8s then. One less X factor when dialing in idle. Thanks for your help!
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Old 10-21-2014, 09:50 PM
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So does that pulley set up net you 8-9psi? Not sure if that's what you're indicating.
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Old 10-21-2014, 09:59 PM
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That is what I am guessing since the stock one is 6 psi. I'm assuming next size up would put me to right around 9 psi on the high end. Just wanting be on the safe side for having enough fuel.
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Old 10-21-2014, 11:08 PM
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Sounds like your should be good with those injectors. I think you're crazy for not running an inter cooler. That thing is gonna make some heat. I'd watch my intake temps pretty close.
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Old 10-22-2014, 10:10 AM
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I know it is, but I am not planning to go nuts with it. The car the SC came from was just a stock JRSC system with Bipes and was entertaining enough for me. I figure the same set up with E85 and a real EMS should be even better and still sane. I am not even 100% sold on the bigger pulley. I talked to Track Dog about it and they said the 62.5mm pulley is the largest they'd recommend without an intercooler. I figure that the charge cooling from E85 will help somewhat beyond the basic non-intercooled set up. Also, I should add that driveability is important to me so that is why I am not wanting to intercool just yet. We'll see how it goes though. Maybe I'll change my tune once I see how it is with my current plan.
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Old 10-23-2014, 02:34 AM
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My set up....M45 + JR Header + JR non-adjustable black box + Racing Beat cat back = reliable fun. I don't smoke any fast cars but I can hang. IMO the only time it is really worth the $$$$ and effort if it is an M62. At least 50+ HP increase to feel the difference otherwise I say it'll be all about the bragging rights or winning the bench race. More fuel for the M45 may not really be effective at least that's what TDR had indicated. I have a friend who is also running a MS3 PNP on his M45 1.8 and I felt no difference with my set up except he needs to tweak that thing every change of season lol. He said it's easy but he never get it quite right even from a tuner. Mine is not quite right either but is always up to task, the least it can handle. Good luck and oh thanks for the chrome door pull handle.
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Old 10-23-2014, 09:21 AM
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I know that just more fuel/bigger injectors won't make a big difference on its own, but E85 should give me a decent bump in power over gas, all things considered. Since E85 gives you a charge cooling effect and allows you to run more advance timing, something supercharged cars can't do under normal circumstances, it should give me a decent bump.

A local STS Miata was running E85 recently and he saw a 3-5% bump in power across the range. So, similar power on the supercharger is not totally insignificant. Not tire shredding, but still not nothing. Plus, for me in MN, E85 is everywhere and is dirt cheap, so I figure it is worth a shot. My goals are not to be the fastest or anything, but it is pretty minimal effort to give it a try. I already have everything but the injectors and the pulley anyhow. Glad you are enjoying the handles!
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Old 10-23-2014, 10:49 AM
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Well I guess doing' something is better than doing' nothing in that case and as you said you have everything and E85 is available and cheap. The only question left is how would reliability be affected. If the MS is up to task in keeping harmony with the new found fuel power. Also now that you have address a weak link hopefully it leads to a strong link. Oh well you'll never know till you try G/L.
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Old 10-23-2014, 10:56 AM
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Reliability should be fine I think. No reason that would change with the E85. In fact, the E85 has muck lower exhaust temps, so that could actually help things a bit.

I do plan to put in a new fuel pump and filter, but that is going to be done regardless since with boost, I don't want to rely on my 24 year old pump. MS can handle it and really, from my reading, it just needs 30% more fuel than gas, so the bigger injectors plus MS are up to the task. If the gains to hassle ratio is too low, I'll likely go back to gas (or sell the SC and go turbo like I am sure plenty of people think I should do).

Any idea what your set up put out for WHP by chance? I never dynod the car I pulled the SC from, but it was entertaining. It was the same exhaust set up you had plus a high flow cat. It had a Bipes for EMS. So, I'd imagine it was similar to what you have for power.
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Old 11-20-2014, 07:45 AM
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I think with E85 the gains in torque are bigger than HP
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Old 12-05-2014, 07:07 PM
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Originally Posted by Adam777
I know it is, but I am not planning to go nuts with it. The car the SC came from was just a stock JRSC system with Bipes and was entertaining enough for me. I figure the same set up with E85 and a real EMS should be even better and still sane. I am not even 100% sold on the bigger pulley. I talked to Track Dog about it and they said the 62.5mm pulley is the largest they'd recommend without an intercooler. I figure that the charge cooling from E85 will help somewhat beyond the basic non-intercooled set up. Also, I should add that driveability is important to me so that is why I am not wanting to intercool just yet. We'll see how it goes though. Maybe I'll change my tune once I see how it is with my current plan.
If anything, intercooling is only going to make your car more reliable by decreasing chances of detonation. I know you like to autocross it on hot summer days. You might be able to get away with it since you want to run e85, but personally I'd go with an intercooler.
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Old 12-05-2014, 09:29 PM
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Dual throttles will cure your drivability issues with an intercooler. Almost every non- dual throttle hot side sc have had idle dip issues (intercooled or not). Got rid of mine with dual throttles and haven't looked back. And I'm still on band aids.

The hardest part is adding the extra pulley wheel to your stock location throttle wheel. After that, just run another stock cable over to the blower mounted t-body. Use the block off plate (you should already have) to cover the idle air opening on Blower TB and you are all good. Well there are a few other small things you have to modify regarding second throttle cable housing mounting but I was surprised how easy it was.
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