208 -.-

No one has yet defined what this alleged "crap" is. If an engine swap is a money pit, you either don't know how to source materials or don't know how to efficiently plan your project. You don't buy parts, you make them. If someone can cut and weld metals, they can make mounts and manifolds. If someone can cut and splice wire, they can make a harness, assuming they are not color blind. This is not a hard project. I don't understand why so many people are against it. Because I'm new to the forum? Or is it because it's an RX-8 and should have no other engine then a Rotary? Hey, give me a 20b for $300 and I'll put that in. Or is because Isuzu aluminum is inferior to Mazda aluminum? (aluminium) Or maybe this is reverse psychology to antagonize me to prove you wrong because you want to see it finished? Whatever the case may be, I'm having fun with it and building what I want. Not what you want, not what she wants, not what they want. If you can not appreciate my dedication or the skills involved then do not troll this thread. All I'm seeing is a bunch of ignorant brand bigotry going on.

An engine is an engine. Here's a challange for you guys. Give me 12 things that make a good engine a good engine. Give me a list of mechanical features. Good luck!

 

Google translate just exploded

 

as you know only two things can cause a skip--not enough spark, or not the correct amount of fuel.
if you have eliminated spark then it has to be fuel--right?
I would check the injector connections first. Then check to see if the injectors are firing.
But another thought--take a vacuum reading--no load , one at idle and one at 2K rpm. It is possible that a small vacuum leak could case what you are describing. Probably not but I always try to not get ahead of myself when dealing with problems like this. I have to remind myself to do the basic tests first
I dont think decel fuel cut is the problem here.

 

wow!!! u know so much about every thing lol you must work for NASA so were did you get your phd in engineering from any way some who things they can get a 20b for $300 and install it must have incredable knowledge and 12 things seriously you couldn't come up with a higher number how about you tell us with your great wisdom nine things that make a good motor good

 

I think Slidin8 said it best.

Mr.Sly - Try reading it again and next time pay attention to context.

 

Honestly what the **** are you saying?

Did you finish school?

The only bit of grammar you used were exclamation marks

 

All I am saying is this has yet to be a 'swap thread' now it is just a 'swap discussion.' And like people who come in with grand ideas of personal supercharging kits, or kickass homemade rear mounts; I think you are just full of cool ideas without the means or experience to make it happen.

It seems as though right now you just like talking about this swap trying to prove how smart you are and your amazing mechanical mind.

 

Because horsepower matters. Torque, within reason, doesn't. Torque is not even "power", it is a moment of force. Horsepower is power, more specifically it's the rate at which work is being performed.

Examples:

1) Rocket powered dragster. Zero torque engine, 3 second 1/4 mile.
2) Fat guy on a bicycle. 300 lb-ft of torque @ 10 rpm, 200 second 1/4 mile.
3) Renny RX-8. 150 lb-ft of torque @ ~5000 rpm, 16 second 1/4 mile.

If you want to play with numbers, it's here: https://www.rx8club.com/tech-garage-...2/#post2474596

 

Your going to try and tell me I won't feel a difference going from 158lb-ft (or whatever it is) to ~250lb-ft? Peak horsepower is meaningless in drag or road racing. It might mean more on the saltflats. The torque curve means MUCH more to me. I'll have a RENs 158lb-ft worth by 2000rpm or sooner. If that can be maintained over a wide rpm range, it'll walk all over a Renesis (on a track). I really don't mean to sound like I'm constantly bashing the Rotary. I think there are many advantages to them. There are also disadvantages to them. All engines have pros and cons. In my case, the v6 will offer me more pros then cons.

I've sourced a high mileage v6 to use for test fitment and mocking up mounts, drivetrain, and exhaust. Once everything is verified beyond a doubt, I'll buy a low mileage engine to use for the final. No sense in banging around a good engine or walking on eggshells during mockup.

The only thing stalling me is finding out how bad my engine is (for resale value) and cleaning the garage.

Oh btw. Don't confuse rotational torque with thrust. A rocket powered dragster has zero "rotational torque" but it has very large amounts of thrust. In a car, rotational torque is converted into forward thrust by means of the drivetrain and tires. I'm sure you know this so you also know a rocket powered dragster has no comparative value to rotational torque values.

 

Can someone find me a dyno graph for a 13b-msp? I can't seem to find one.

Attached is what Spitfire logged on the 6VE1 (3.5L) they use in the Spitfire. They're not using a very optimized exhaust manifold so I doubt there's much exhaust scavenging going on. They are using a standalone so one can assume the fuel and timing may be better optimized then Isuzu's tune. They use the Isuzu stock intake from the truck.

It looks like the torque is falling quickly over 5500rpm. I'd guess by 6500 it's dropped below 200lb-ft. Looks like they peaked 270lbft@4200rpm and about 265hp@5500rpm. I wonder if knock events caused the erratic curves.

 

What's wrong with exclamation mark !!!!111111++++++!!!!!!!!!!!



Also : Putting a truck engine into an 8 is like putting renesis engine into a truck - only different .

 

It didn't make much sense to me either but then again, what makes a truck engine other then the cams/intake tuned for more torque at a lower RPM? I justified it because people are getting 200k miles out of it lugging around a 4300lb Trooper. In a 3000lb car it's a cakewalk. Typically truck engines are built stronger but usually heavier. Other companies like Nissan and Mitsubushi are using cast iron blocks in their v6 trucks. Isuzu went aluminum and although it's an open deck block, it has siamese cylinders. That's better then jiggly jugs. (wait for it)

THE most important reason for considering this engine... transmissions options.

Check out this little wonder from Isuzu. 3.5L 75deg v12 NA 730hp@13,500. Not bad for 1991. McLaren considered it for the F1 when Honda turned them down. They decided to drop Isuzu for something with more proven track time. I thought that was interesting. I would have never guessed Isuzu to have made anything worth a **** in racing.

 

Those exhaust manifolds are beautiful!!!!

And i love the intake trumpets too

 

I've been digging around trying to find a video of it. No luck. I'd LOVE to hear it run. Anyone have a 5-axis and a couple of 2JZ heads kicking around? I'll buy the billet!!

EDIT - Nevermind. It's the 1GZ-FE

 

 

 

If transmissions are an issue just go with an f20c or an sr20det engine. Swap the bellhousing on your OE transmission and you're good to go.

 

It was a test. You failed. You were arguing that a 66% increase in torque offsets somehow the drop in hp to your beloved V6. This in general is not true. Of course one "feels" a difference with a higher torque engine. The fat guy on the bicycle will pull an RX-8 for the first 5 feet of a drag race, too, but the car has ~800 times the horsepower (over any significant period of time).

The comparable between a car engine and rocket engine is power. Though if you wish, one can measure thrust at a normal tire's surface-to-ground interface for comparison. Power = Thrust x Velocity.

HP = (Torque x rpm) / 5252, assuming SAE units. Half the torque at double the rpm is exactly the same as double the torque at half the rpm.

 

Give this guy a break. You make my head hurt. I feel like I'm back in my physics class. He wants more torquey Isuzu v6 which makes less peak hp than 13b. Why? Who cares? Some people laugh at us for buying RX8. Some people sneer at people for buying something that doesn't get over 40mpg's. My gf thinks I'm dumping money out the ocean for my 3 rotor project and would much rather see me swap an electric motor into an RX8. Obviously I don't see it the same way.

Many swaps go unfinished and abandoned. It's just the nature of the game. Stuff happens in life, and you just can't anticipate everything. This guy's a self-proclaimed resourceful backyard mechanic. Frankly, I wouldn't care if he graduated MIT and is a team principal leading an F1 team. Let him post some questions, and if you know the answers, feel free to share your knowledge. Ganging up on people with an unfamiliar view is this forum's culture. Sadly, it only takes a few ignorant members with a lot of time on their hand to create such culture. I just wish it would stop. This isn't kindergarten.

 

^ He states over and over (in one way or another) that the renny and is slow because of low torque. He praises this v-6 over and over because of high torque. The point is, the view that torque ==> acceleration is simply not true. (Though it is widely shared in the automotive world).

From the second line of the OP's first post:

The impression I get is that the knowledge sharing he had in mind here is only going one-way. My attempt to point out that power is what matters, failed entirely. (Sorry if physics makes your head hurt, but your hurting head doesn't make the physics any less true.)

From my POV, he is perfectly free to put anything in anything on his own nickel. He is also free to pass off false facts as knowledge, but also on his own nickel, meaning don't expect it not to be eventually called out. If that constitutes being picked on, so be it.

 

I have an SR20 sitting in the garage ironically. An F20 swap just makes it an s2000. A 6 cylinder swap is more unique I think. Sounds better also.

What is it your misunderstanding? I never said the Renesis is slow. I said it lacks low end torque. Having to clutch the thing like a 2-stroke dirt bike get's anoying. Say I get 250hp from the v6. That's not much higher then the Renesis and won't be much faster in a race. If you truly want to understand the difference, you'll have to start crunching numbers through the drivetrain and tires. My rear wheel torque is going to be over a much wider range then the Renesis. Tell you what, tell me what the RX-8's rear wheel torque is at say 65mph. Pick any gear you want.

 

Fair enough. I briefly took it personally because I was at the receiving end of them when I first logged onto this forum. :P

 

So far the important questions have gone unanswered. Most of the posts seems to answer the question "How do you feel about a v6 in an RX-8" ...which I never asked. People are open to their opinions and I welcome them. Unfortunatly there's no facts stated in which their opinions are based.

I still need a stock Renesis dyno graph. Anyone have one?

Sorry HiFlite, I missed that post. Hopefully I can help you understand. Lets assume two engines have equal horsepower and all other things are equal except the torque curves. Same car, same weight, ect. In that situation, the torque curves of the engines will determine which one will "win the race". Say they both make 150lbft of (peak) torque and 250hp of (peak) horsepower. The only way to know which engine would outperform the other is to look at the torque curves.

I'm not sure that I can properly explain what I'm saying other then showing you a dyno runs but understand the curves and drivetrain play a huge role in calculating performance. You can't simply say engine "A" will outperform engine "B" without knowing many other factors.

To help explain...

Lets take engine "A" and supercharge it. Lets also use a supercharger that's undersized and underdriven so that engine "A" can not make any more peak torque or more peak horsepower then the NA engine "B". Which is going to outperform the other? The horsepower and torque ratings would be equal. Does that mean the vehicle performance is equal? Absolutely not. Although they are rated equally, engine "A" will win the race because it's torque comes on much sooner then engine "B".

It sounds like your might only be comparing peak numbers? 250lb-ft and 250hp is greater then 158lb-ft and 232hp. Only an 8% gain in peak horsepower.
The lower rated engine could outperform the other engine if it's torque curve is so wide that the average torque across it's usuable power band is greater then the average torque across the other engines band. If we bring transmissions into the equation it'll complicate things even more because now we're shifting the torque and RPM all over the place trying to maintain peak engine output (horsepower).

Hopefully that helps and yes I understand I can't rev the v6 to 9000.

 

Stepping away. This sentence was very telling. Good luck with wherever you land.

 

That's entirely not needed. Perhaps if you bought a running car instead of a rolling chassis all this bullshit could be avoided.

HiFlite is right in what he says about torque. It's not the holy grail of everything automotive related. A 2 stroke 250cc engine with no torque is faster than most 350-400cc 4 stroke engines for a reason.