Pessimistic tach?

[capt_furious]

I just finished installing my Autometer tach into the stock gauge pod...even sits behind the stock lens, just like the original. Brand new tach, it's this model. I configured and installed it exactly according to the instructions, even tested it prior to installation using clip leads.

 

My stock tach hasn't worked since I bought the car, so I've been playing it by ear. I guess I'm either not used to an engine revving as high as the L28 does, or this tach is off by a couple grand.

 

I find myself shifting when I wind it out at around 5500 indicated...that's where I'm used to doing it. It sounds / feels as if it's going to hurt something if I go higher.

 

However, the stock tach out of a 280 goes yellow at 6500 and doesn't go red until 7000.

 

Is my tach off? Should I really be worried, or should I wind it out and enjoy? Do twice pipes make an L series sound as if it's revving higher(they sure are frickin' LOUD)?

[auxilary]

we set it for 6 cylinder mode, if memory serves, right?

 

and you're probably getting valve float at 6k rpm... mine felt the same way. What is it idling at?

[capt_furious]

We did. Switch #1 down, #2 up. Idles right around 1k when it's completely warmed up. Idle set screw is all the way out, should be at around 850.

 

Yeah, it runs out of power and gets a bit rough approaching 6k. You're right, it's not a pessimistic aftermarket tach, it's an optimistic factory tach!

 

At 5500, that L28 sounds like a buzzsaw on crack. It's wild.

 

Side note, just saw an R8 for the first time tonight. Looks much better in person than in photos. I've always thought they were ugly, 'til I had an up close look.

[woldson]

Mostly stock l28 is going to run out of "breath" at 5500.

 

With what I've done, (lighten fly, electric fan, little richer, more open exaught (man I hate spelling that word)) mine poops out around 5700/5800, depends on the day;).

 

I've never had a problem with valve float on stocker springs, even old ones, up to 6500/6800 rpm.

 

In my older ZX with a cam, I ran it up there all the time. I do mean all the time!

 

 

One time on my older ZX I missed a fast shift to 4th, I saw the tach pin! For that split second the engine shook kinda violently, and you know what ran through my mind.

 

Pampered it for a few miles, counted my blessing and continued to flog it until retired.

 

 

On a side note, with a balanced/ lighten fly and pressure plate I can be a 4000 grand plus and not realize it until I look at the tack.

 

It is so smooth it feels like a honda 4 banger, however, if you tell others I will deny I ever said that.....

[auxilary]

actually inline 6s are better balanced than 4 bangers (which is why most of today's i4s have balance shafts).

[capt_furious]

Hrm...my L28 isn't stock, but there are no internal changes, just bolt-on stuff; N36 intakes (original to the car, kept them from the flattop setup), SUs, twice pipes.

 

I don't think I've ever experienced valve float, so I wouldn't know what to look for. I just know that approaching 6k, the engine SCREAMS and I'm afraid to push it any further. It's not a good idea to push your daily driver that hard.

[eec564]

Sounds normal to me. As long as you aren't knocking at high RPMs you should be fine. You'd know if you were getting valve float even if you didn't know what it was. The engine feels like it hit a rev-limiter, kind of, falling on its face, rattling and miss-firing. It's not the taper-out and out-of-breath feeling a stock engine gets at 5500 under load, choking its way up to 6500.

 

By the way, did you ever fix your fuel supply issue?

 

-Eric

[capt_furious]

Still having issues, not as bad as they used to be. Primary problem(hesitation / dying from a dead stop) was solved, I'd just neglected the oil in the carbs...DUH.

 

I'm pretty sure my fuel pump isn't up to snuff. I'm going to try replacing it with a Carter GP4070, my primary concern right now is where to mount the thing and running wiring for it. I'm hoping to do this next weekend.