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

[Z-Dreamer]

As Mark mentioned above, the pushrods and the rest of the valve train of the SBC is not conducive to such RPM’s,... I would like to hold onto the possibility of finding away around the valve train issues.

 

The valve train issues for a sbc at Ultra High RPMs are (1) Valve spring pressures, (2) Push rods and (3) Cam flex.

 

(1) High valve spring pressures are unavoidable in a high rpm, high lift, high flow, 2 valves per cylinder engine due to the weight of the large valves.

 

Ever notice that the High Rev exotics use 4 valves per cylinder? One of the reasons is a smaller valve weighs less and requires less spring pressure to prevent valve float.

 

Higher spring pressures also place more stress on the rest of the valve train.

 

(2) Push rods experience NASTY harmonics above 10,000 rpms and can literally shatter/explode!

 

(3) Cam flex is BAD and directly related to shaft diameter, valve lift, spring pressure and RPM. In short, the more spring pressure and rpm, the more cam flex is experienced!

 

The BEST solution would be the use a 4 valves per cylinder head capable of high rpm.

 

Like this for example, http://www.araoengineering.com/

 

Unfortunately this would NOT be an inexpensive option.

[Guest TeamNissan]

32v 502 rat ughhhhhhhhhhh so nice.

[Pete84]

 

Like this for example, http://www.araoengineering.com/

 

Unfortunately this would NOT be an inexpensive option.

 

Absolute beauty . . .

 

EDIT

Would a LS block be more capable of higher sustained RPMs?

[datsun40146]

Ok so as long as were talking cost, what would a motor with these specs cost to build? Since BRAAP has posted so much machining information (thanks) on how it would be done in his shop I was wondering what he would charge to make this motor a reality?

[BlackBeaut]

Briefly detouring back to the Cerbera AJP8, here's Clarksons review of it including a brief interview with Peter Wheeler (then TVR boss) about the engine. Lots of lovely braaaaaping going on

http://www.youtube.com/watch?v=ASpdWtXmce4

 

Cheers,

Rob

[Hailstorm]

Briefly detouring back to the Cerbera AJP8, here's Clarksons review of it including a brief interview with Peter Wheeler (then TVR boss) about the engine. Lots of lovely braaaaaping going on

http://www.youtube.com/watch?v=ASpdWtXmce4

 

Cheers,

Rob

 

that sounds great.

 

I'm looking forward to building a 377 sbc which revs decently high. That'll be about all my budget can afford and probably the best sound/highrpms I could get anyways.

 

BTW, if anyone has a 377, would you mind recording a sound clip or video of it going? I'd like to see/hear some of what its capable of before I dive head deep into doing one.

[BRAAP]

that sounds great.

 

I'm looking forward to building a 377 sbc which revs decently high. That'll be about all my budget can afford and probably the best sound/highrpms I could get anyways.

 

BTW, if anyone has a 377, would you mind recording a sound clip or video of it going? I'd like to see/hear some of what its capable of before I dive head deep into doing one.

 

Well, it shouldn’t sound any different than any other SBC or even BBC. No magical exhaust note differences with a destroked 400. I’ve heard 283’s that sounded JUST like a 454 and vice versa. The exhaust system will a have a lot of influence over how much different it sounds than any other SBC. As for how high it will rev? Depends on how stout you build the bottom and the combination of parts that compliment the RPM the bottom end is capable of revving to. There are 383 strokers turning 7500 RPM, which would sound very much like any other 7500 RPM small block using that same exhaust system and mufflers. Equivalent quality parts for the 377 combo might allow 8000-8250 RPM, but the rest of the parts such a heads, cam etc must compliment that. Being as it is a 3 ¼” stroke, it can safely rev a little further than the 3.48” stroke of the 350 with equivalent pistons and rods. For the ability to rev even higher, use the 3” stroke from the ’68-’69 Chev 302, or maybe the 3.1” stroke of the ’75 Chev 262.

 

In short, what you are really after, is a sound bite of pretty much any SBC with a similar exhaust system and mufflers that you plan to use, revving to the RPM that you plan to build your engine to.

[BRAAP]

The valve train issues for a sbc at Ultra High RPMs are (1) Valve spring pressures, (2) Push rods and (3) Cam flex.

 

(1) High valve spring pressures are unavoidable in a high rpm, high lift, high flow, 2 valves per cylinder engine due to the weight of the large valves.

 

Ever notice that the High Rev exotics use 4 valves per cylinder? One of the reasons is a smaller valve weighs less and requires less spring pressure to prevent valve float.

 

Higher spring pressures also place more stress on the rest of the valve train.

 

(2) Push rods experience NASTY harmonics above 10,000 rpms and can literally shatter/explode!

 

(3) Cam flex is BAD and directly related to shaft diameter, valve lift, spring pressure and RPM. In short, the more spring pressure and rpm, the more cam flex is experienced!

 

The BEST solution would be the use a 4 valves per cylinder head capable of high rpm.

 

Like this for example, http://www.araoengineering.com/

 

Unfortunately this would NOT be an inexpensive option.

 

Ah yes, Multi valve heads as produced by the OE, with the cams "in the head" are conducive to MORE RPM due to the main fact that the cam shaft is overhead, i.e. less over all valve train mass. (Honda, Toyota, Mazda, Nissan etc are excellent examples of that technology). Now you offered those really cool high flowing heads as a solution to our problem, but at this point, without further information to back up any claims of mega RPM, I’m seeing those heads as a step backwards regarding the valve train issue. On their site in the SBC section, they are claiming 9000+ PRM with their “unique valve gear arrangement”. What is that “unique valve gear arrangement”? Those heads still utilize the “in block camshaft, lifters, and push rods”. Now those same cams and lifters are opening 32 valves instead of 16. Granted, those 32 valves are smaller, but the overall valve train mass would now be greater, which will only exaggerate our “valve train stability/cam flex issue”, right? Maybe they have special unobtanium valve train material that is mega light weight, but I doubt it. Based on your camshaft flex theory, the only real improvement I see that those really cool heads have to offer for this theoretical high RPM V-8 is air flow. At this point, I’m not seeing the mechanical issues such as the valve train stability at such RPM being solved with those heads, unless their “unique valve train gear” uses some different timing gears etc, which we should be able to use with the standard SBC heads and valve train as well, (they claim their heads still utilize the standard cam and lifters).

 

 

As for the cam flex info, good info, and it all makes sense. I’ve read a bit of Vizards writings, Harvey crane, and few other sources, and cam flex was talked about, but only in regards to how we use the SBC traditionally, not to the that wild dream of mine of 10,000+ RPM . Being as you seem to be well versed in SBC camshaft design/technology/etc, is cam flex totally dependent on RPM only, or is it also influenced by the cam lobes as well, i.e. intensity, amount of lift, also possibly spring pressures, overall valve train mass, etc?

 

Also, If you don’t mind divulging your sources, where are you getting your information? Your answers to my questions leave so many more questions that as a professional performance engine builder myself, it would just be easier for me to read them first hand so I don’t have keep asking you to fill in those holes.

 

TIA,

Paul

[ROVdriver]

Just bought a 1uz for my Z...

[Careless]

Just bought a 1uz for my Z...

 

so is it a 1u4z now?

 

great stuff, get some ITB's on thurrrr!

[proxlamus©]

uh oh.. something just sparked my interest

 

http://video.google.com/videoplay?docid=-8960669985955675027&q=Ferrari+Testarossa+sound+clip&total=21&start=0&num=10&so=0&type=search&plindex=3

 

Why is it that a Ferrari 512 motor.. a HORIZONTALLY OPPOSED 12 cylinder can sound identical to the Ferrari V8s and flat crank!?

 

I mean the Subaru WRX's have a flat four.. and sound like harleys! probably because of the LL RR firing order or something.

 

I guess this is also the design of the crankshaft as well?

 

Thinking about it.. I guess a Subaru and Porsche sound wicked different.. but the Porsche has a HO6 versus a HO4

[Guest TeamNissan]

Ya the subi svx has a ho6 as well. They sound good but I think they are in a category all their own. I don't know if I could compare any ho engine to a v8 using any crank.

 

They can sound REALLY good though.

 

BRM made a H16 in the late 60's, so 2 ho8's stacked using 2 cranks and 8 cams. Now thats crazy lol.

[Hey_Allen]

Regarding the Subaru exhaust sound, most of that is due to the dramatically unequal length exhaust headers causing the exhaust pulses to be out of sync.

 

The stock subaru headers run the left bank exhaust around the front of the engine, then back to join with the right side, and up to a turbo, or just down to the cat and out.

 

When some of the performance minded drivers went with equal length headers to tweak efficiency, they found that the 'boxer growl' vanished, much to the dismay of a number of them.

[Guest y44nissan]

You could try finding a late model Lotus turbo v8. It has a small displacement v8 with twin turbos and a flat plane crank. Very Nice!!!

[josh817]

Try Brammo Motor Sports. They sell a little 2-4 liter v8 motor (I can't remember how big the motor was but it was small) and in, street setup it had like a 10k or 11k redline and race was 12k I think. Made 400 hp. I asked how much and I think he said 35k but if thats what you want then there you go. They also sell v12's and such. The one I like makes 1100 hp stock and with a turbo or a blower makes 1500 hp.

 

http://www.brammo.com/index.php

[Guest TeamNissan]

Ya, brammo is also putting out a 10 liter v12 american super car soon. N/a makes like 800hp and 1000tq. They tested it TT too and it made something like 1800hp lol.

[datsun40146]

I still think that the best solution to this problem is to use the destroked SBC with a single plan crank. Yes, the custom crank may cost 2-3 thousand, but even if you had another 5 or so in GOOD internal parts and heads then the motor would only be at most 8,000 USD. That is a-lot less than 35K in my book. I think that mabye I will try and make this motor a possibility? Hmmm, I'll have to talk to my machinist and braap about that crank...

[Guest TeamNissan]

Ya but if you take that rt why a sbc? Idk I would do a dohc v8. Could destroke a modular ford 4.6 and maybe even keep the blower . Lots of parts support pretty modern etc...

[OlderThanMe]

VH45DE

4.5 liters, DOHC, 278hp stock, revs to 6,900RPMs, 6 bolt mains, and they are available at the local yards pretty cheap.

They make about 450 boosted hp on stock internals at 10:1CR.

Someone was also talking about downsizing the rod journals just a little and modifying some SBC rods to fit... That opens up almost infinite and cheap piston options.

Sounds really good too!

OTM

[datsun40146]

Well I have heard that the ford 4.6 has a bit of trouble fitting in the bay of the Z. Secondly I hadn't considered the VH45DE, however the aftermarket support required to make this motor "exotic" hasn't arried for the 45de yet, or if it has i'm not aware of it. The way I see the cheapest way to get that exotic sound is the destroked single plane SBC. The block would be dirt cheap as would some decent heads, throw in some forged internals, a decent cam/springs and you'd be set. Plus the SBC swap has been down SOOO many times that they will almost bolt right into a Z with off the shelf parts, can you say that about the vh45de? Don't get me wrong the vh45de is a GREAT motor but for the purpose of this thread I think the SBC would be a better choice.