THSCC Forums

Howdy All,

In preparing my old 1.8 Miata engine for installation into my '93 car, I have become concerned about the old injectors in it.

A. The motor has been sitting around since June '04 - inside of shed
B. I'm upgrading the fuel pump to a 255 LPH unit
C. Fuel lines are being replaced

Issue 1: Injectors - They've been sitting around with their internals dried out for quite a while. I know some submerged fuel pumps rely on the fuel as a lubricant and can burn up when run dry. I wouldn't be surprised if fuel injectors rely on fuel for lubrication too, hence my concerns. Aside from just squirting at them with carb cleaner, can they be disassembled and cleaned/freshened up? I don't really want to get involved with sending them off for cleaning/calibration. However, what would be the time frame and expense of such a service? Any good/bad experiences with such service providers out there?

Issue 2: Injector/Head Seals - They look like they are hard plastic. Going to forced induction will mean that the pressures inside the intake manifold will no longer be "atmospheric". They don't strike me as being a pressure resistant seal, so I'm concerned about blow-by around them. Are there any aftermarket applications that address this concern or am I just paranoid?

What other "minor" issues might I be overlooking?

Thanks,

KB

_________________
“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

While I am unsure about Miata specific, conventional injector seals are rubber. If they appear to be hard plastic, my guess is that they are in need of replacement.

As for injector cleaning, I believe there are places that will perform the service for ≈$20/each. However, since you will be adding forced induction, I would assume that you would require larger capacity units, especially in light of your somewhat lofty goals.

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Rich
http://www.v8mongrel.com/

Have the stockers rebuilt/rebalanced, no question. Les's BRP kit included an extra injector in the intake manifold, so you don't have to upgrade the rest of the injectors. I don't know about the upper stage kits.

If you have visions of 280 rwhp, you better start thinking about upgrading the internals to support that kind of power. ~230rwhp is the conventional wisdom upper limit on stock internals. Many have done more that that on stock, but you're probably pushing your luck at that point.

Have you ridden in Les's car? ~210rwhp is wicked fast in a Miata. 280 would seem to be a recipe for wicked wheelspin exiting most slow corners...

While I'm trying to spend your money, put flares and big wheels/tires on the list too.

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Tom Freeman
'98 M3/4/5 | '93 Spec3 325i | '12 TSX sport wagon | '03 Tahoe
Team Silver Bullets '91 240SX

I had these guys clean my injectors a month or two ago. They are quick and the prices are on par with everyone else. I think it ran me ~$60 and 1 week to ship, clean, and re-ship.

http://www.affordable-fuel-injection.com/

Email: info@affordable-fuel-injection.com
Phone: 248-393-1621
Fax: 248-391-2491
USPS: Affordable Fuel Injection 7575 N. Hollister Rd. Elsie, MI 48831






Paranoid, but I know you so it doesnt suprise me. My DSM had a similar setup for sealing the fuel injectors, at 22+ psi not a drop of gas leaked anywhere. I dont think you are getting anywhere near that.

_________________
02 Focus SVT
STF 9

Yeah, with you at L'burg and Donnie Barnes at Sanford. I should have the basic kit on by VIR Full. That'll have me ~180rwhp. With a 2300 lb car, my weight to power ratio would be 12.8. By VIR North, I hope to have at least an A/A intercooler added. That oughta get closer to a w/p ratio of 12.


Definitely in the long range plans. Remember Doug Gubbins' white Miata? I was almost scared in that thing at VIR South on a wet track!


Guess I'll be sending them a package tomorrow. That's a reasonable price to pay for peace of mind.

Thanks for all the input so far!

KB

_________________
“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

Fixed that for ya!

Im serious too, blocking the radiator with a FMIC and then putting down more than double the factory rated HP and heading out on track is a recipie for trouble.

_________________
02 Focus SVT
STF 9

I'll also have a bigger and better radiator by then (If not sooner).

_________________
“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....