Looking for Engine Advice PLEAAAAASE!

[iaconsultants]

To get a high reving engine you will end up giving up on your low end take off without slipping the clutch and lettling your revs go high. I designed and built a turbo Z some 18 to 20 years ago. It would rev no problem at 8 to 9k but I never went over that. I also ran a big Rayjay, aluminum rods, had a custom head made from a blank, custom cam, 194 and 202 valves. The car was insane and the moeny I spent was even more insane. You can ge the power you are looking for out of a 4 cylinder but the engine will not last unless you spend more money than its worth. If you are dead set on non-honda, well I would suggest taking a Supra Twin turbo straight six (these engines seem near bullet proof). Get rid of the turbos (since you want NA, I would stay turbo myself) and build up the engine. There seem to be lots of performance parts for these engines and they are around 15 to 20% more than working with chevy parts from what I have seen. Some of the cars I have helped with have dyno tested at 800 to 1100hp but they are Twin turbos but that engine is so tough it seems like you would have to try to break it. I hope you build what you want, even though many here are doubting tom's and think you are going the wrong way and I kind of do too but that is why you are here and I would say we should help and wish you luck.

Robert

[auxilary]

Perhaps what you really want is a 4age motor

[Gollum]

Now if aux would only finish his B13 you could find out how a rotary feels in a Z....

 

Now you've got some incentive aux. Finish the car and come w00p my azz.

 

I want you to know jl87ma, what you're sacrifising for your goals. HP/MPH. A NA 2.0 liter motor will not get 300hp efficiantly. A 300hp force induction 2.0 liter motor would be considerable less NA, we'll guess around 180-220. So with 300 hp force induced you get the low RPM miles per gallon of a 200hp motor but the high RPM HP of a 300hp one. This is one of the biggest benefits you're throwing out the window.

 

Another thing you're going to be throwing out the window is full RPM power. Either way NA of FI you'll be going to high RPM to get power in a low displacement motor. In street driving rudypoochris's 5.0 240Z would probly beat the same 240Z that has a 4 cylinder with 50 more hp. Full range tourque can have a huge impact on street driving. It makes a car much less streetable, but it also means low HP can push wide gears much easier.

 

So what your engine wants set in stone for you is that your car will be:

 

1. Poor gas milage if high HP is attained

2. Normal gas milage at normal or slightly above normal HP

3. Poor low RPM accelleration

4. Linear acceleration (great for a track car)

5. Easy/simple maintainence

6. Bulletproof (if accompanied by rev limiter or conscious)

 

And in the end, RPM limit isn't determined by cylinder count.

 

Oh, and rotary engines are reliable, just not past 60k miles

 

Under those requirements I'd go with a KA24DE, tons of tourque. But it's also 2.4 liters, not a small 4 cylinder. And it pays it's price in gas milage.

[phantaz]

anyone remember the olds quad4??? and before you start hissing and booing..when it first came out and the weird "hybrid" olds aero thingy came out it sudddenly became the 4cyl of choice for kit cars and im sure they had them in rwd format.. beefed internals and turboed those things really put out some power... but once again.. 80k is about the life before another rebuild. i know i know.. not import but it would be different =0)

[Guest Phil1934]

How about Mercruiser 470? There's a poster on the HAMB board that would like to sell his old B'ville engine (196 MPH). You can add any of several BBF heads. I even talked to ARAO about mine and they had a 4 valve head but $3K was too rich for me.

[rubin]

how come no1 had said anything about nissan's FJ20's?

awsome NA or turbo motor. Designed originally for rally and other racing, but later put into street cars. it was used on S12 silvias and i thik DR30 skylines. these motors are BULLETPROOF. Aftermarket support is "decent", the heads are able to breathe very well and ITB's can be used and it can be revved very high.

This will definetly be an "original" idea

 

lots of info on www.fj20.com . This engine is kind of rare, but I dont think it should be too expensive compared to sr20's or rb's.

[pparaska]

Why the hangup on a Toyota or Nissan NA 4 cylinder?

 

Do you realize that to get, say 240 hp out of that, you'll need to really rev it high to get to it's peak hp, like 7800rpm?

 

Do you realize that if you design and engine like that it will have no really decent torque (like above 200 or so lbft) below say, 5000rpm? It'd be more like 165 lbft peak at 6500 rpm.

 

Have you ever driven a car that weighs, say, 2830lbs that has that kind of a power band? If so, did it excite you?

 

I've just given the peak power and torque for the 2175cc S2000 engine, and the weight of the 2005 S2000.

 

Go drive an S2000 for a week.

 

If that's what you like, go forward, and determine how much more power you'd want in your Z.

 

Then consider:

1- How much money you'd have to spend on the upgrades to get the power you'd want and keep it reliable (you'll need more rpm most likely, which stresses the shortblock and valvetrain)

2- What the lowest usable rpm will be, i.e., where is the engine just so flat and limp that you'd hate driving it in that rpm band. This rpm will rise as the peak hp and torque rpm figures go up, which you'll need to get more power.

 

BTW, how much is going to be enough hp to make it seem fast enough for you?

 

Have you ever ridden in a 2800 lbs car with 400 hp or more?

 

If so, did it excite you more than the 250hp 2500lb car above?

 

Would the engine in that 2800lb, 400 hp street car be a candidate if it gave you a more affordable, more reliable, more streetable rpm torque/power band, but it was a 6 or 8 cylinder engine?

 

Would the engine in that 2800lb, 400 hp street car be a candidate if it were a turbo 4 cylinder or turbo 6 cylinder?

 

In addition to learning about NA power curves, their dependence on high rpm to make "impressive" power, and what that means as far as having little torque for MOST if not ALL of the street-type rpm range, I would advise you to ride in or drive different engined cars.

 

The saying "there's no replacement for displacement" (sic, NA displacement) is not just some silly phrase - there's a bunch of empirical data behind it.

[Silent]

you want a safe 11k?

hmmm

alright

rb26dett

full build, head, bottom end, around 30k in the rotating assembly alone. about 5-6k in the head.

 

then comes the engine managment. the v-pro can handle it with a xs engineering ignition box.

 

aka, dieman motorsports r33

[ProjectSR20]

Does anyone else think that the saying there is no replacement for displacement is too over used? Im not trying to start a flame war but I am curious. All the V8 guys seem to say it over and over. In my experience, when you are talking about the N/A world this holds true. But when you get into turbo's I think it somewhat goes out the window. I know that V8's have more torque and horsepower off the line than a 4 cylinder, but what about peak power?? Yes, a flat power curve with gobbs of hp and tq is cool, but isn't peak power peak power?

 

Example: A friend of mine has an '87 Camaro with a 350, a few bolt ons and such. I had an '89 civic with exhaust, header, cam, ignition....the list goes on. I know for a fact that off the line he was making twice the power I was. The thing that makes me think that the old saying is over used is because of the way I have noticed the engines reved (the speed). He had a way better power curve than me, tons of HP and TQ off the line where as mine didnt kick in till about 3-4 k rpm. Even though my redline was a couple thousand rpm's higher than his, I could get to it faster than his could. So we were putting out about the same peak power, but due to the lower ammount of mass in the rotating assembly I could get to my peak power faster than him. Does this make any senes to anyone else here or am I just ranting about something thats over my head?

 

I would really like to hear what others think.

 

***pparaska what about a 400 hp engine in a car that weighs 2100 lbs? I believe that was about the specs on Amir's 240 w/ an sr20. I think that would give some, not all, V8's out there a run for their money, dont you??***

[ProjectSR20]

I guess now that I think about it some more, if you turbo a v8 then you are going to still make more power compared to a turbo 4. So maybe I am just ranting and raving about nothing.....

[pparaska]

How about this update for the no replacement for displacement saying:

 

"There's no replacement for the product of (displacement) times (boost pressure)."

 

What I mean is displacement(1) * boost pressure(1) = displacement(2) * boost pressure(2)

 

Engine(1) has boost pressure(1), Engine(2) has boost pressure(2)

 

If all else is equal, they will put out very similar peak power. But peak isn't EVERYTHING.

 

What I was getting at was that if you start out with a little engine, you need to boost it to make power. No problem with that.

 

But if you read my post closer, you'll note that I added (sic NA displacement) to that saying.

 

I think it's really crazy to ask a 2 liter NA engine to give you 500 hp and expect it to be anything close to streetable.

 

So don't take my "no replacement for displacement" as a bash against smaller engines with boost - I TRIED LIKE HELL to make it clear I wasn't doing that!!!

 

As far as your Camaro vs Honda story, the Camaro was probably over 1000 lbs heavier.

 

So we were putting out about the same peak power, but due to the lower ammount of mass in the rotating assembly I could get to my peak power faster than him.

I seriously doubt "rotating assembly" mass, inertia had much to do with that. Search on the forums - there are a few threads that debunk the "327/302 rev quicker than a 350" stuff. Again, I think the real issue was probably the Camaro vs Honda weight.

 

I agree the 2100 lb SR20Z 400hp Z will give quite a few NA V8 Z's a run for their money. But many NA V8Zs also have a full interior... Amir's car is very impressive - but it's closer to a stripped out Honda than many street Zs are, IMO. He did that on purpose, I understand that. But I'd want any race between his car to be against a similarly equiped lightweight 240Z with a V8. Aluminum dash, stripped interior, etc.

[ProjectSR20]

Point taken. Im sorry if I came across making it look like you were bashing 4 cylinder engines. That wasn't my intent at all. The last thing I want to do is bash you because I have read a good portion of the posts you have made and you seam like a great, knowledgeable guy.

 

I also agree that there is no way you could make 500hp all motor out of a 4 cyl and make it streatable. I never intended to make it seem like that and I would laugh at anyone who thought they could.

 

You also do have a point on the Camaro being 1000 lbs heavier. I guess its like comparing apples to oranges. I probably should have thought of a better comparison, but that was the only thing coming to my mind at that moment.

 

And about the lower ammount of rotating mass....I wasn't trying to say that WAS the reason. That is just something that makes sense in my head when I think about why, in my experiences, smaller motors seem to rev faster than larger displacement ones. This could just be another point I am totaly wrong on. So sorry to anyone that I have upset with my last post. I just take what I know of physics and how the world works and try to apply that to motors.

[grumpyvette]

http://shafiroff.com/pro/555_965.asp

 

http://shafiroff.com/pro/737_bigchief.asp

 

why not get crazy

[pparaska]

Point taken. Im sorry if I came across making it look like you were bashing 4 cylinder engines. That wasn't my intent at all.

No cry, no foul. It's cool. I just didn't want to be taken the wrong way. I think 4cylinder engines have there place, but I would go with a turbo or supercharged 4cyl if I put one in anything over say 2300 lbs for a "fun" car.

 

I also agree that there is no way you could make 500hp all motor out of a 4 cyl and make it streatable. I never intended to make it seem like that and I would laugh at anyone who thought they could.

My comments on that were not directed at you. I think the original thread starter needs to really do some research on what a horrible, unstreetable beast a NA 500hp 2 liter 4 cyl would be like in a street car.

 

You also do have a point on the Camaro being 1000 lbs heavier. I guess its like comparing apples to oranges. I probably should have thought of a better comparison, but that was the only thing coming to my mind at that moment.

Good comparisons are not as easy to come by as some might think. Weight and driver talent need to be very similar, and gearing needs to be optimized for each engine. Then you can make a decent comparison. It's not so easy to find two cars with those similarities, etc.

 

And about the lower ammount of rotating mass....I wasn't trying to say that WAS the reason. That is just something that makes sense in my head when I think about why, in my experiences, smaller motors seem to rev faster than larger displacement ones. This could just be another point I am totaly wrong on. So sorry to anyone that I have upset with my last post. I just take what I know of physics and how the world works and try to apply that to motors.

Well, rotating mass has some effect, or oval track and road racers wouldn't be going to all the expense of low inertia flywheel, clutch, pressure plates, etc. So the effect of 8 pistons versus 4, etc. is not inconsequential. But if you think about the differences the two engines (NA 4 cylinder vs NA 8 cylinder) have in available horsepower across the useful powerband, with optimized gearing, the inertia of the shortblock moving parts is secondary.

[ProjectSR20]

Well, rotating mass has some effect, or oval track and road racers wouldn't be going to all the expense of low inertia flywheel, clutch, pressure plates, etc. So the effect of 8 pistons versus 4, etc. is not inconsequential. But if you think about the differences the two engines (NA 4 cylinder vs NA 8 cylinder) have in available horsepower across the useful powerband, with optimized gearing, the inertia of the shortblock moving parts is secondary.

 

I guess I never really thought of it that way. I had to read that about 4 times to really understand what you were getting at, but now I think I got it. You are the man. Thanks for opening a blind persons eyes.

[pparaska]

Well, it's a idea that has been proposed by people in those "302/327s rev quicker threads" - that the power production does more to accelerate the car than the inertia of the engine does to hold back that acceleration. I'm not saying it's a totally correct way to look at it, but it seems like a valid theory to me.

[TheNeedForZ]

I did an estimate on the effect of reduced rotating inertia before. I was trying to see how much faster in the quarter mile will a stock 240Z be if the crank rod journals were drilled hypothetically(but in reality the L6 crank cannot be drilled because of the oil holes.) The result : about 0.02 sec faster. In one of David Vizard's book, he said that a V8 with drilled rod journals will cut 0.07sec off in the quarter mile in a 10 second car.

 

The effect of reduced rotating inertia is insignificant compared to the effect of increased displacement.

[NotSuperBbutZ]

The BIG PROBLEM with the F20c or 22c and any other engine that has a 10k redline, is hte torque is shitty, you gotta slip the clutch mass and launch HIGH lest you get taken by a minivan, if you want a good engine that'll still rev respetivly and get good power, do an sr20det

[rubin]

best 4 cyl - FJ20

best 6 cyl - RB26 or 2JZ

best 8 cyl - LSX

[Guest temeculaz]

Man 7000 RPM you want to get some where fast it sounds like or you just like buying tires anyway I have a friend who put a L28 stroker moter in his 240 with 6 T/B's just like you want and it was one of the fastest's 240's I have ever seen but it was not cheep!! It took its own computer to run those and his ignition sounded like it was something straight out of an INDY car. But it was fast, I think he spent some where around 15 to 20K on the moter but it seemed reliable. Hope this helped.