Getting the 1UZ up to 9,000 RPM?

[GSMnow]

Just a little clarification. I have programmed a few EFI systems with alot of data logging so this is fact.

Given a normal constant pressure (over manifold) fuel pressure regulator, the highest duty cycle will occur at the horsepower peak. That is the rpm when the greatest amount of air is flowing requiring the greatest amount of fuel per second.

On the other hand, the torque peak will require the greatest pulse width. The torque peak is where the engine is breathing the greatest amount of air for each revolution. This is also the rpm point that will produce the highest cylinder pressure and will likely be where pinging will occur. This can sometimes make it neccesary to increase the fuel flow a little more to be safe.
To make the math a little easier, the injectors should make 400 hp at 100% duty. So if you have a motor that can make 300 hp at 6000 rpm, it would only need about 75% duty cycle up there (about 7.5 ms of on time) with the stock 251 cc injectors. But if this same motor makes 320 lb ft at just 3000 rpm (this figures out to only 180 hp) the duty cycle is then just 46% but that is a pulse width of 9.14 ms.

The rough rule of thumb is that you can feed 2 horsepower for every pound/hour of fuel injector. CC/MIN is very close to 10 * lb/hr. This still works out to 400 hp on a set of 8 251 cc/min injectors, but that is well over the recomended 80% duty cycle you should shoot for when designing a system. My turboed 22RE was running 4 550 cc/min injectors to nearly 90% duty cycle. That is feeding about 1980 cc/min which would theoretically be 396 hp. This resulted in a 12:1 a/f ratio at a bit over 300 hp at the crank. Thanks to a crappy 2 valve head and turbo exhaust restriction, the BSFC is abit low on that motor. The same injectors feeding a Mitsu Eclipse 2.0L turbo motor would be more like 360 hp at the crank and a serious non turbo motor with a tuned intake and exhaust system would have to make close to 400 hp to use that much fuel. I figure the 1UZFE with the "economy" F head design should be at least as good of a BSFC as the turbo Mitsu motor.

Gary M.

 

[brad]

what would it take to get the 1UZ into the 9000 RPM range? or higher!? i mentioned this to Lextreme and he said that ppl in AU are reving there 1UZ's to 9500 RPM. what part of the motor is most delicate, or the weekest at high revs? im assuming its all about the valve train, and that if you have a fully build valve train, along of course with forged internals, and a balenced crank, that getting into the 8-9000 rpm range it quite do-able. anyone know about anything on this topic? :?:

your right there are some people over here running that RPM and much higher!!

some even see 11000 and 12000RPM but those engines are in race boats and get changed every 10 or so hoursof work or about every 3 or 4 races. because the 1UZ is a very cheap engine over here.

the weak point is the rod bolts and they are the only bottem end part changed.
they also run these engine with twin super chargers too get that RPM.

i know of a drag car over here with a twin turbo 1UZ with completly stock internals. this guy didn't even rebuild it. it just straight out of the front cut and into the drag car with twin turbos and 30 PSI the engines make about 1300HP. he runs it until it blows up then just gets an other front cut. The cuts can be had here for $AU 1400

 

[SCV8]

With Toyota's background in 4 cylinder engines, and reliability, I would expect these engines to work great at around 8,000 rpm.
FI would be the easiest way to get to that rev., but with some parts that we really haven't seen yet(cams), it'd be very simple.

 

[turboteener]

THe 1UZ has a nice rod ratio, so spinning it to 10K should not compromise the limits of piston speeds. My calculations show piston speed to max out at 8750 FPM 105 degrees into crankshaft rotation. That is with a 10K rpm limit. You guys should look at rods from an H22 Prelude engine. I belive they have similar dimensions, the pistons could come from B series Honda.

 

[Lextreme II]

Turbo....

Yes... H22 is very similar....There are few threads about this already.. would be interesting to revisited again......

 

[sbcelicagt]

Since I am curious to know more, I picked up some specs of the 1UZ and did some calculations.

Bore: 3.44in
Stroke: 3.25

From the Auto Math book, here are a few results from calculating the Mean Piston Speed:

RPM ---> MPS in feet/min
6500 ---> 3518 fpm
7500 ---> 4060 fpm
8500 ---> 4600 fpm
9000 ---> 4872 fpm

For a street engine those are some very high numbers. As indicated in that book, anything above 4000 fpm is considered the upper limits of a reliable engine.

If you don't care about reliability, the next problem would be such that the piston speed is so high it is outrunning the flame front. Not conducive to making horsepower.

IMHO, I would try to keep the engine under 7500rpm if possible unless you don't plan to keep it a while. Everyone's preferences are different though. I consder "I while" at least 50,000 miles. It also depends on how you abuse your engine. Short bursts to 9000rpm trying to beat some bonehead on the highway is not too hard on the engine. Running your engine above 8000rpm for 20 minutes while racing around a roadcourse circuit in 100 degree weather is very hard.

 

[turboteener]

You can change piston speed by using a longer rod, but I really wouldn't worry about it. The stock ratio is 1.80 that is one of the best you can get. Outrunning the flame front is not a problem, especially if you have designed the combustion space for a fast, effiicent burn. The FI boys trun 18K and don't out run the flame speed. The NASCAR boys are turning 10k with a push rod engine, no problems.

A NA engine is very hard on parts, RPM = ruined peoples motors. But, the sound of a 10k RPM race motor is hard to beat. For most street cars put a blower on it, if you can handle the cost and maintainance build an engine that will pull to 8k or beyond.

The piston speeds of some stock Honda four cylinders is much higher than "common limits". They have designed around those parameters and get very good durability. Remember that the 4k mean piston speed was a mechanical limit from the past. There are many engines that go over that. My stock 1.6 cervix motor sees a max piston speed of 6622.66 at 6800rpms. Got 200k on it. Now I don't baby this one, it gets revved over 7k on a normal basis. Point loads go up to 7100 FPM. The Covette C5R engine is running the 24hrs at piston speeds over 4116fpm without any durability issues. Rod ratio is important but not the only issue.

 

[E30 lexus]

Hi there guys I'm new on this forum nd I hve learned alot I'm busy with a single turbo 1uz in a e30 bmw tht has no space bt wat I wana knw is how safe is it to rev my engine after the turbo is mounted with 750cc injectors any advice with a stock engine with 200k on it nd service everytime on 5k were can I set my limiter to nd wat boost can i run on my t70 twin scroll turbo