valve float...
 

Hey! I have an other question... At how many revs the engine starts to have valve float on a pro 1.8 DOHC 1991?

It can go without any problem to 7000 rpm and a little more? because i don't know at what rpm cuts off the rev controller...does these pros have rev controller?

I know this engine has its max hp at 6500 rpm but i'm just asking...

I need tips, my brother has a Suzuki Swift GTI and he challeged me in a 1/8 of mile and I need some tips from you racers guys!

Mine is a BP from a second gen. It redlines at 7000 and the fuel cutoff is at 7200.
I'sd imagine yours would be the same.
As far as valve float, I don't know. That can depend on the condition of your valve springs as much as RPM.
Its a non-interference engine anyways so its not a huge concern.

As long as you haven't played with the timing (too much) and you run good gas, they will be fine. The 1.8 DOHC can rev until it hits the rev limiter. If I remember correctly, the rev limiter is 7400rpm and the fuel cut off is 7600rpm.

non-interference engine
 

What's a non-interference engine?

I feel when the engine is going up 5500rpm the car slows a little bit, can that be a wrong timing?

no

the valves have no interference with the pistons anywhere during the stroke in a non interference engine, so if valves started to float at high rpms or you broke a timing belt, it wouldnt seriously damage anything...in an interference engine the the valves are at risk of coming into contact with the pistons should valve float or a broken timing belt occurs...get it??

Redlines is 7000.
Fuel cutoff is the "rev limiter", @7200

If the fuel cutoff is at 7200rpm, how was I able rev hit a limiter after that on my BP? I've done this on my old BP and my dad's BONE STOCK 91 LX.

inaccurate tach.
Its not uncommon for them to be off a couple hundred RPm especially in the higher ranges.
Same thing as your speedo. They really aren't 100% accurate all the time.
The only way to be dead accurate would be to hook up a signalling device from the #1 plug wire, the way timing guns are done.

I am curious and not clear on this ...what is valve float?...

It is went a valve don't return to the close position.

Let's figure a door with a spring that close the door, like in every shopping mail..etc.. A client open the door. the door close itself. but if the spring is not strong enought, the door take more time to close. lets call that, shopping mail door float.

so on a car. the lobe on the cam shaft push the valve open. then the valve spring pull the valve back close, but if the spring arent stiff enought, the valve dont close at the right time.

oh ok thanks..