safe RPM's

[ben_unruh]

I have another newbie question...

I have a strong 1.3 engine (AAPA "Better than OEM" engine) with probably 7,000 miles on it, a 6.5 T-case and 31" tires

My question is this: How fast can I spin my engine in 5th gear on the freeway?
I can keep steeping on the petal in fifth passed 5,000 RPMs and keep accelerating, but know this cannot be good for my engine. So what can I dependably keep it at on the freeway for prolonged periods of time.

[LiftedZuki]

How fast are you going? anything over 65mph I feel like I am hovering over the road! I hit 70-75mph down hill this last weekend, crazy!!

[ack]

I also have an AAPOA engine. 1.6 8-valve. Got it in '02.

I NEVER run it over 4300 on the freeway/Interstate. At that RPM with 30" BFG AT/KOs and 4.625 difs (4" SPOA, OTT steering, Toy DC DS in the rear -everything else is stock) I can get 70 MPH without excessive shifting on hills. 65 at 4000 all day. Any faster and you are asking for trouble in my humble opinion.

You can't have it both ways - a rock crawler AND an Interstate daily driver.

[catzuk]

On your particular engine, I am not sure, but I'd think it would be fine running in the upper rpm band if its broken in. May have to call the vendort that built it for their opinion.

If you ask Ken (geckocycles) he will tell you 7000 is fine

As for stock, Before my block change and even now, I do 65-75 daily driving mine down interstate and highways without any worries. 31's, spoa, spooled rear, locked front and mine is stable as can be. Does not get floaty, and doesn't wander. And yes, it rock crawles with the best of them including some competitions.

I try to keep my rpms around 4000 on highway. In 5th at about 70 I am at around 4200. It runs smooth to 5000 and will keep going strong, but I need the motor to last so I won't push it over 5000 too often.

[skyhiranger]

I like to keep mine at under 4K on the highway (and generally under that offroad too....but I have hit 5500 or so a few times offroad). My theory is, the lower the RPM you run it (to a point) the longer the engine will last.

[riev zuki]

Originally Posted by skyhiranger

I like to keep mine at under 4K on the highway (and generally under that offroad too....but I have hit 5500 or so a few times offroad). My theory is, the lower the RPM you run it (to a point) the longer the engine will last.

This is good info. I keep mine to 4000-4300 on the interstate. If you look at the stock Sami tach it starts redline at 6500, I've reved my 1.6 8v to 6000 many times. The 1.3 will rev easier than the 1.6.

[240hpsammy]

i never worried with the rpms on my stock 1.3 , drove it on highway 4 yrs everyday
going uphill and downhill and reved way past the red line and never seen the end of it.

a small displacement engine can usualy withstand more rpms then bigger stroke ones.....
(old technology) ones

[Fastspec2]

Originally Posted by catzuk

On your particular engine, I am not sure, but I'd think it would be fine running in the upper rpm band if its broken in. May have to call the vendort that built it for their opinion.

If you ask Ken (geckocycles) he will tell you 7000 is fine

As for stock, Before my block change and even now, I do 65-75 daily driving mine down interstate and highways without any worries. 31's, spoa, spooled rear, locked front and mine is stable as can be. Does not get floaty, and doesn't wander. And yes, it rock crawles with the best of them including some competitions.

I try to keep my rpms around 4000 on highway. In 5th at about 70 I am at around 4200. It runs smooth to 5000 and will keep going strong, but I need the motor to last so I won't push it over 5000 too often.

Yeah, but thats because with a real induction system (like his 4 carb) they will do it without getting pissed off.
I am of the opinion, run it hard, when it starts to smoke, re-ring it. You can rebuild one of these things for beer money.

[riev zuki]

Originally Posted by Fastspec2

I am of the opinion, run it hard, when it starts to smoke, re-ring it. You can rebuild one of these things for beer money.

You must drink some cheap ass beer.

[geckocycles]

Maybe I'll get around to doing a leak down and compression test today. Mine is g a bit, mostly when periods of engine braking, and is feeling down on power now. I certainly have been buzzing the hell out of it. I suspect I am rich on the pilot screws and also valves are probably needing a good lappin.
5500 has good power and will run easily for extended periods of time but these carbs are loud WOT above 4000. LOL.
Bone stock exhaust.

[Jaunty]

you need bigger tires! either that or small t-case gears like 4.9's.

i think of it like this, the higher the rpms = the more wear on your engine. you want the rpms in the power band, not below or above.

[geckocycles]

And where do you think the power band is on a 1.3?
It is way the hell up there. Higher than I like to run because I go deaf. LOL

[Fastspec2]

Originally Posted by geckocycles

And where do you think the power band is on a 1.3?
It is way the hell up there. Higher than I like to run because I go deaf. LOL

With a stock intake and a weber mine made peak at about 5200. with the 4 carb setup, peak was at 7100. But it still made more HP at 5200 then the stock intake and weber. You just got an extra 2000 rpm of workable horsepower. Not to mention something like 37% more peak HP

[ben_unruh]

Thanks guys,
I know i was gettin low gears when I ordered my 6.5's
I typically run from 3300-4500 on the freeway, and have gotten up to 90 on flats at about 5,000 rpm, but I dont like to keep it there. I guess I will try to stay in the slow lane from now on and keep it under 4200 rpms

[LiftedZuki]

WOW. A samurai at 90mph would make me soil myself. I honestly felt that at 75-80mph, I was pushing the limits of a stock SPOA sami. I could tell my dad was kind of freaked that we were going that fast!

[ben_unruh]

Originally Posted by LiftedZuki

WOW. A samurai at 90mph would make me soil myself. I honestly felt that at 75-80mph, I was pushing the limits of a stock SPOA sami. I could tell my dad was kind of freaked that we were going that fast!

My samurai is very stable, but I do tone it down whenever the conditions aren't perfect. I am young and , and have to tell myself to slow down, but it's just so hard when you still have gas pedal left!

[LiftedZuki]

I am 18 and do some crazy things but IDK about that..

[zukijames]

my zuk doesnt go over 70..... and thats just cause i dont like to watch the fuel burn in the cummins.... as for on its own power... it hasnt seen over 40 in months but i do rev it pretty high off road no tach but it seems around 5+ quite often