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Exotic "SOUNDING", high revving V8! Read "ENTIRE" thread before posting!!!

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I have been up to my elbows in BMWs the past year... So why not try a BMW S85-V8 swap. They look like they might fit in the S30 bay...

http://forum.e46fanatics.com/showthread.php?t=605194&page=5

from the E46 fanatics forum

 

http://i230.photobucket.com/albums/ee186/lukask2005/?action=view&current=m3teststart.flv

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I've still been stuck on researching these VFR engines, trying to figure out on paper how to really do this.

 

I was thinking that the best way to go about the transmission issues would be to disable the stock one, and fabricate a custom setup to adapt it to something common, light, affordable, etc.

 

But the ratio options for this engine's power band just doesn't work. Sure, you might only loose 2k rpm when you rev a L28 to 8k, but the farther up in RPM you go the more RPM you loose, since it's a %, not a consistent number. So when you're reving to 11k, even a "close ratio" commonly available transmission just doesn't cut it. Point being that any commonly available tranny that's going to cost LESS than the engines themselves is going to really hurt the overall feel of performance of the setup.

 

So I've been working through figuring out how to use the stock tranny. It's a 6 speed with these ratios:

 

2.846

2.062

1.578

1.291

1.111

0.965

 

I figure the only way to get the transmission to hold the weight of a Z, even at only 1,800 pounds gutted and lightened, would be to use BOTH transmissions...

 

Luckily the primary and secondary shafts both have snouts at both ends that poke out of the block. So really what's needed is to machine the front end of the primary shaft to accept the output of the other engine's primary shaft.

 

Something I don't think I could even engineer on paper until I have the engines on hand would be the shift linkage setup.

 

I can't stop thinking how bad arse a real slap stick sequential 6 speed would be in a Z.

 

Something is indeed wrong with me.

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so it took me two weeks and some annoyance, But I read the whole length and am stuck on the single plane crank in a 350 I had originally thought short stroke big bore itbs would give me the sound I was after, but 180 degree crank would help imensely. I fail to see the reasoning behind 10,000 rpms I built my stock car to do 7,500 all day long. the other thing i am not sure about is power I think a 250 horse motor would be fine with me and then throw on a twin turbo should be good but will that adjust sound greatly? I dont think it would but turbos are not an item I am familier with.

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Another approach is to try and match up the exhaust pulses just be rerouting the exhaust primaries. In doing that we end up with 180 degree headers as used on the original Ford GT-40 race cars. (Pairing up the 2 inner cylinders of one bank with the two outer cylinders of the opposite bank). The exhaust note does become more crisp, but still has a coarse rumble to it. I have no idea why it doesn’t exactly duplicate the crisp BRAAAAP exhaust note, but it doesn’t, otherwise I just spend the time in fabricating 180 degree headers as there is PLENTY of room under the oil pan of a SBC V-8 S-30!

 

 

1. The Ferrari engine is much smaller than an American V8. F355 is 3.5 liters compared to typical American V8 of 5 to 7 liters.

2. Ferrari F355 has 5 valves per cylinder..

 

 

I think an X-pipe gets you 90% there.. Then make a small engine. Also, a short exhaust system helps. Perhaps a side exit behind the front wheel?

 

Listen to this GT40.. 180 degree headers plus short exhaust system equals exotic sound. I think it sounds a bit like a deeper version of the F355:

 

http://www.youtube.com/watch?v=Hcb3zHZuEUU

 

I would be willing to bet that the intake system is a factor, too. Try an ITB system and it will look good and perform well in addition to sounding good.

 

Here is a large engine with just the X-pipe and some spintech mufflers:

 

 

Do this in a 3.5 liter engine and bingo!

 

Come to think of it.. I wonder if it isn't the engine size, but rather the exhaust pipe size... smaller engines tend to have smaller pipes. food for thought..

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.....

 

Having said that, the X-pipe is just a second best option to 180 degree headers. There is NO difference between a flat plane crank and just using 180 degree headers on a dual plane crank. OK well there are differences in the balance and weight which will allow a flat plane to rev quicker.. Anyway power production with an X-pipe has been shown to be within a fraction of a percent off from 180 headers. There used to be a bunch of good articles at drgas.com but I don't see them now.

 

But I would be willing to bet that other factors play a very important role in the sound:

-- 5-valve design and the progressive nature of the valves (they open the outer valves first i think)

-- engine size of 3.5 liters

-- rotating assembly weight (or lack thereof)

-- camshaft specifications (overlap, etc)

http://ferrarichat.com/forum/showpost.php?p=36869&postcount=18

-- compression ratio

-- short exhaust length, and muffler configuration: http://www.ferraricars.org/ferrari-f355/drivetrain.html

 

Ideally you need to match all those parameters, but my feel is that with the flat plane crank or 180 headers, AND a small engine size of 3.5 liters, you would be 80% there..

 

Check this out:

http://www.youtube.com/watch?v=LLqflRvUgKc

 

I realize the idle is choppy, but listen when it is under load. If the engine were smaller, I bet it would sound similar to an F355.

 

 

This is looking more and more like you should just get that F355 engine and be done with it :) Rather than spend $5k on something that is not quite right, why not spend twice that and get the real thing? Then figure around 2k per year for maintenance and upkeep, doing the work yourself.

 

http://www.ferrarichat.com/forum/showthread.php?t=198430

Edited by BRAAP
Edited out BRAAP's arguments not pertinent to the discussion.

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I'm kinda surprised about the referrences to building a Chevy 302. I talked about building one of those a good few years ago and got flamed like I was in hell. Nice to see there is some interest in it. Chevy 302 can be good to about 9K RPM if blanced well. Great package for the Z because it doesn't hit with too much torque off the line.

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I'm kinda surprised about the referrences to building a Chevy 302. I talked about building one of those a good few years ago and got flamed like I was in hell. Nice to see there is some interest in it. Chevy 302 can be good to about 9K RPM if blanced well. Great package for the Z because it doesn't hit with too much torque off the line.

 

Sorry to hear you were "flamed". I've seen those threads before (not specificially yours) and I remember chiming in on a few that said for streetability for the same money (or less, since valvetrain stuff is expensive to turn 7k+rpm) much more power is available with more cubes.

 

Hmm. How about a 4.165" bored Dart SBC block with a 3" stroke, the right cam and heads, with 180 degree headers and IR induction? You'd have a 327 cubic inch (5.3L) engine capable of those rpm and the even sound of the 180 headers.

 

I will agree on the X-pipe thing. At anything above abot 2500 rpm, my 407ci Z with block hugger headers, x-pipe behind the trans, and dual mufflers at the rear panel sounds very even. Not like a ferrari, but it doesn't sound like your typical V8 hotrod. The X-pipe evens out the pulses very well. Sorry, no sound clips.

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I remember those 302’s. High compression and short stroke. They came in the Z28 from the early 70’s as an answer for Trans Am racing. (I might be wrong on my facts.) I will never forget the song from that one. I don’t think a low compression turbo of the same size will emit the same noise as the crackle from a high squeeze engine. Just my thoughts…

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First of all I'd like to thank all of you for offering your knowledge & wisdom.

I have been wanting that F1 note in my 240Z for so long,so i dug up the internet for this, if you take out the finacial factor it very easy.

If you want F1 power & sound then just go for an F1 engine!

http://www.engdev.com/index2.htm

Match it with a Sequential gearbox & your all set to go.

I would love to do this swap cuz i can afford it but living in Kuwait restricts me =/

I'll just stick to the RB26 for now >=D

I hope I sparked your interest.

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That's just not fair to either brand.... That's a pig's body stuffed onto a greyhound's legs. It doesn't really seem to offer the benefit of either.

 

It's actually worse than the analogy I use often for various crappy modern dodge cars, which is a pig in a rhino suit.

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hey guys, how about using one of those 4 cylinder crankshafts used in midget racing? I have heard they use one of the banks of a domestic made V8(v8 Cut in half) they should have about he same dimentions of a small block crankshafts, how hard can it be to make them work as a v8 flat crankshaft?(they are flat but just for 4 cylinders)

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Interesting point, but you wouldn't happen to know the rod width and dimensions of the main bearings on those cranks, would you?

 

NOPE, but I have heard many Midget racing engine are based on the Chevy II engine, wich was very closed related to small blocks, so the dimentions should be close enough,

 

so how hard is to fit 2 rods on one journal?

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NOPE, but I have heard many Midget racing engine are based on the Chevy II engine, wich was very closed related to small blocks, so the dimentions should be close enough,

 

so how hard is to fit 2 rods on one journal?

Well I feel the crank would have to be re-drilled since the stock oiling hole would pretty much fall directly between the two rods and most 4 cylinder engines have a rod width roundabouts 1inch while the stock chev rods are .940 width as well. If you managed to wedge two custom rods on there the width would probably be well below .700 width which is starting to get skinny.

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