Custom VK build up...

[AMV8(1day)]

Okay, so someone please feel free to shoot me down but at least give me reasons why this basic setup wouldn't work:

 

My ideal finished product:

4.809L V8

95.83/83.33 Bore/stroke

600 est. HP@8700-9000RPM

350 est. lb-ft.@7500RPM

 

My method of pulling it off:

A JDM sourced VK45DD with the following modifications:

Bore taken from 93 mm to 95.83.

Stroke bumped from 82.7 mm to 83.33.

Massive reworking of the heads geared toward high-RPM horsepower and enlarged valve diameter without causing shrouding.

Complete valvetrain replacement with aggressive cams ground to run out of breath between 8700 - 9000 RPMs, Titanium intake valves and valve springs with hollow gas filled exhaust valves.

ITB setup Fabricated with approx. 3.11 intake runner area to put the peak torque around 7500RPM.

Custom titanium con-rods with forged aluminum pistons.

Custom billet steel crankshaft.

A final compression ratio around 11.5:1 to 11.9:1 on E85

 

This gives me a 4.809L engine with a 1.15 bore/stroke ratio,

about a 9000RPM ceiling with a 4921 piston speed FPM and a 25 piston speed MPS,

Not a hundred percent on deck height, combustion chamber volume, rod length, piston design, ring setup, pin placement, head gasket thickness and material, still having issues tracking down the stock dimensions and what kind of dimensions I would have to work with once I started modifying it. I would obviously like to keep the rod/stroke ratio between 1.6:1 and 1.9:1, as close to 1.75:1 as possible (around 145.83 mm) while still leaving room for piston ring placement and trying to keep a nice combustion chamber shape with flat to dished pistons while maintaining the afore mentioned 11.5:1 - 11.9:1 compression by playing around with the head gaskets and combustion chamber.

Pretty sure cryo-treating, nitriding, or shot peening will be necessary but not 100% on which to go with depending on the application.

Plasma-moly coated rings will probably have to be used to cut down on friction and help with endurance.

 

The engine already provides 4v per cylinder, direct injection, VVT, lightweight aluminum block with aluminum heads, and was already built with an oversquare bore/stroke ratio, making it in my opinion a perfect choice for a naturally aspirated, high-revving beast.

[Jerminator96]

You either know a whole lot about engine building (in which case why bother asking) or you subscribe to all of the 'old wive's tales' in the business. Don't take this as a put down, you've obviously taken the time to educate yourself and that is a lot more than most people will do.My number one question (before I question any other aspect of your engine) is what do these heads flow? After all the porting and whatnot what do you expect to flow through each intake port? I would say if you can manage 300cfm you can pull of 600 hp (as a rough guess). If you can get 330cfm a monkey could build your shortblock and you'll still hit 600 hp.If you really want big power out of that motor I would suggest you contact David Vizard in Charlotte NC and ask him about doing a 'Poly-Quad' conversion on your heads. After you do that you can decide whether the rest of the build is even necessary.Just my $.02

[AMV8(1day)]

Hey, thanks for the feedback, I've got a big complicated reply sitting on my comp at the house but I had to go to work before I could finish it. But appreciate the $.02.

[Clifton]

To add to what jerminator said. Head flow is what makes the power. I don't know what the VK45's flow but I know the VH45's flow a tad over 250 at 28". The VK's have smaller valves too so I can't see them being any better. I also wouldn't bother increasing the stroke such a small amount. The gains per $ wouldn't get you much, atleast compared to say a cam(s) swap. I don't know if anyone makes them for the VK but they are available from a few people for the VH's. If customs it will get expensive. HP per dollar, this sounds like an expensive engine. You could probably find a VRL or used Judd, ect indy engine for about the same.

 

I know you weren't asking but VH's use a pretty big rod compared the the VK's and the valves are larger, saving money on both. NZ guys make 500hp with the VH41 w/ a 10:1 CR and a carb. Unless money is no object I would rethink how much you want to spend to get 600hp Don't get me wrong, I like VK's but I also like spending as little as I can to make HP. Don't get caught up in Ti con rods, billet cranks, ect if it's a street car. If it's an all out class race motor, that's different.

[Jerminator96]

That's not a bad point, you can get a 3.5L IRL motor for $15000.I got the impression that he was going to do a custom crank anyway to run reliably at 9k rpm, so at that point why not add a little stroke?

[Jared]

You're gonna spend way to much doing that. A VK56 with high comp pistons, good rods, headers, ITBs, and good engine management will make that and you'll spend way less money.

[Gollum]

It's a noble idea, but it's gonna cost a lot unless you work at a machine shop and end up doing 90% of the work yourself.

 

As others have said, the power is in the head. Those power levels won't require a massive redesign of the bottom end on that engine. 600hp out of 4+ liters is nothing for most production engines nowdays. You can reliably boost a 1UZFE to 500hp out of 4 liters, and the bottom end is fine. Just changing the pistons out to some lower compression forged pieces raises the HP limit a ton, well past 600hp, out of a measely 4 liters.

 

I wouldn't worry about finding a motor with the perfect features, such as bore/stroke ratio, as much as I would worry about finding a V8 with heads that flow amazingly well.

[AMV8(1day)]

While I by no means would call myself an expert, I have spent a decent amount of time around engines and have been looking for a V8 that revs like a Honda for awhile, first looking at BMW's M62 engine but having issues with some of the metals used and the unnecessary price tag involved just for the honor of working with a BMW engine.

As for the head flow, obviously at least 290cfm would be required to pull this off, but I have yet to find solid numbers on the stock heads. Before I could go ahead I'm probably going to have to track down a set of heads and get them on a flow bench.

As far as the rest of my build, its kind of an exercise in ideal ratios, I realize that these numbers could be reached much easier with more displacement or forced induction, but I'm basically looking for ultimate efficiency with the Honda F20C and the Ferrari F430 4.3L V8 as primary inspiration although I am still trying to get a reasonable amount of torque (albeit a tad on the high end of the RPMs) to be able to putt around town without having to strip the car down to a 1700 lb race car or rev to 7 grand just to get through the light.

 

IRL ENGINE SUGGESTION

I've read your comments and appreciate all of them although I don't think I have been clear enough as to my primary motivation behind this build. Although I like the idea of owning an IRL engine in theory, it just wouldn't be a practical or even feasible foundation for a still primarily street based, almost full weight production vehicle build. It would seem that tracking down an IRL engine, finding a fabricator capable of dropping it in and linking it up in a street reliable fashion, finding a tuner and tranny builder capable of working out the dozens of kinks involved with a race engine never intended to go into a production vehicle, having to scrounge around and/or fabricate any and all parts required to maintain such a high maintenance diva of an engine, the serious lack of torque bordering on completely unusable in a street setting, oh, and the fact that it would completely defeat the purpose of the initial undertaking. Wow, thats a big sentence but my point is I still see a far more reasonable cost to benefit within the production based VK as well as the fact that the entire point of the build is to take an admittedly good engine to start with and put it in the realm of exotics not often seen outside of Italy, using an independent engine builders passion for mechanical perfection.

 

HEAD FLOW CONCERNS

As far as the head flow, I appreciate the heads up, I was afraid of that which is why I was holding off on solid numbers until I could get some impressions from others with VK head experience, and yes I've seen some of the reports coming out of NZ and their insanely potent VH's. I figured the heads were going to be my biggest bottleneck, but I'm hopeful with a good enough port and polish, larger valves, hopefully I can go far enough out without valve shroud that I can pull this off. But that is why I'm considering going alittle over the deep end on other areas to try to compensate and give the heads as little reason as possible to not live up to expectations. the poly-quad technique may be a viable solution, although I still haven't nailed down how much help creating a swirl effect would be versus a straight up reshaping of the

Plus I'm planning on going to E85 for the build due to the higher octane (around 105), lower burn temp, cleans as it burns, and as an added benefit, its cheaper then 87 around here even with the decreased fuel economy.

 

HIGH END AND CUSTOM PARTS

The pricetag on this build while alittle extravagant, isn't astronomical. I'm doing alright for myself right now and have the added benefit of still not being trapped in the expensive confines of family life. The Ti rods are because of the piston speeds I'll be hitting even with the relatively short stroke, and knowing me, I'll be hitting them plenty on the track and occasional street sprint. The small increase in stroke is more for the ideal stroke ratios and limits of piston speeds than simply taking the hot rodders "bigger is always better" road. If I was going for that I would simply factor in the 5.1L stroker kit made by Impul or even simpler, go with a VK56. Plus, has anyone ever heard an ITB V8 or V10? If I were a religious man I'm sure god would be speaking to me in those high notes.

 

OTHER MISC. WAYS TO MAKE POWER

Obviously there are easier ways to make 600 horses: 383 stroker with carb, heads, cam, and headers could pull it off, turbo 302 with heads and cams could easily pull it off, an almost stock 454 with a cam and head combo could do it with so much torque behind it I'd be eating up rear diffs all day and still lovin it, a 496 would be even simpler after the stroker setup, an RB25DET swap would easily accomplish pretty much any power level I could ever want, an LS stroker 406 could easily accomplish this, etc., etc., etc.. Thats not the point of the build, this build would obviously cost more than most of these other builds and almost all of these builds would be easier and simpler. But I'm sure that there are plenty of people on this forum that understand doing a unique build for the sake of being unique or the love of a certain engine or type of power delivery.

[Jerminator96]

You are obviously afflicted by the same 'engineering disease' that I have. There is no cure, and I wouldn't want it if there was.I wish I would have known you wanted to do this a few months ago because I gave away a set of vk45 heads back in march. The one interesting thing about the Nissan V8s is that the bore centers are nearly identical to the SBC. With some block machining you could make them work with relatively little money and then take advantage of a 4-4.185 bore and a huge after-market. I know you can buy Cup Car cranks from wrecked stock cars with low mileage fairly cheap, and they turn 9000rpm almost continually for 500 miles. Just something to think about.A side note: don't get hung up on low end torque. Torque is just a measurement of force, horsepower is the amount of work being done by that force. One benefit of being able to spin the motor high is the amount of gear you can use. An F1 car only has 300 lb-ft of torque but it can stay in first gear up to 19000 rpm. I'm sure you know this, just reminding you.About the PolyQuad conversion: the main idea behind the PQ is increasing combustion efficiency. The big problem with the pent roof 4 valve combustion chamber is that at high RPM with a lot of duration (which is exactly what you'll have) the fuel tends to flow right out of the still open exhaust valves. This gives you less power at best, and dangerously lean burns at worst. The PQ was developed to fix this.I'm all for your project, and if there is anyway I can help you let me know. I'm all about building something to test theories, be original, or just for bragging rights. Heck one of my current projects is an H2O2 powered motorcycle. In the future I plan on building a light weight, high-revving 2.8L V8 to drop in a 280Z. Like the old coventry-climax 2.0L motors they had in the Alfa Tipo 33. Sure I could probably just get a 2.8L Ferrari V8, but what's the fun in that?

[Clifton]

As for the head flow, obviously at least 290cfm would be required to pull this off, but I have yet to find solid numbers on the stock heads. Before I could go ahead I'm probably going to have to track down a set of heads and get them on a flow bench.

 

Someone already did (non siamesed). That's were I got the 250 cfm at 28".

 

Most Hondas have a longer stroke than a VK/VH45 and have no problems revving on steel rods. You might not need or might not make power to 9k anyway.

[AMV8(1day)]

Thanks for the vote Jerminator, I may be just alittle obsessed, as you may have noticed. I study engine theory whenever I can, when I'm not around engines I'm thinking up new combos, viable chassis' for monstrous twin turbo v8's, lightweight 2.6L low-boost I4's dropped into Lotus Elise',

As far as poly-quading goes, I'm not 100% on how that would help with an engine equipped with Direct Injection. And that brings me to the head flow issues, I'm sure they had to augment the intake and exhaust ports in some way to make room for the injectors, I can track down a set of VK45DE heads for about $100, but getting ahold of a set of J-spec VK45DD heads will probably prove to be problematic. Thats one of the reasons I'm still holding off until I can have them checked, getting a set of heads up to at least 290 from a possible 250, resulting in a 16% increase would be pretty tough to pull off. But I want to retain the direct injection or else there is obviously no reason to bother with a JDM engine, especially an uncommonly exported one.

[AMV8(1day)]

And clifton, thats where the head re-working, aggressive cams, upgraded valvetrain, and high lift valves are for. The rest of the engine already supports high revving for a v8.

 

PS

Love the silver Z, It looks great.

[Jerminator96]

Ah, you did say you were using direct injection, didn't you. Well that does change things. No I am not sure that the PQ conversion would help, but it certainly would not hurt to ask. If nothing else Mr. Vizard might have some ideas on how to get 290+cfm out of those heads.Just out of curiosity, what pressure are the injectors working at?

[AMV8(1day)]

I've searched and haven't been able to pull any numbers out, but considering I'm going for double the horsepower and E85 I'm thinking I'm going to have to find a considerably larger set that will fit the block and be able to spray a sufficient amount in the smaller window left for direct injection.

[Tony D]

FYI, a couple of years ago, those IRL engines were being sold off considerably cheaper than the quoted price.

McMeekin Bros back east were not privy to the Nissan IRL clearinghouse, so bought an Aroura IRL engine for a similar price. They put it in a 240SX.

 

They move at over 200mph at Bonneville if I'm not mistaken...

 

The CORR Racing Trucks were running the 5.6 at 8200+ rpms and making a gob more power than the stated goals above (other than rpm range). Basically forged pistons and isky bumpsticks. They used the factory sump that whole first season. Some nice OEM engineering there!

[Jared]

I like to overthink engine engineering as well, but to a point .05 worth of rod/stroke ratio,5cfm, etc... isnt going to matter much in a streetable engine so don't beat yourself up over minute details. I'm doing a VK56 as soon as I have the time to get it running. I like the engine quite a bit, its miles over square and has a 1.6x rod/stroke ratio, six bolt mains, and four valve DOHC heads with big ports on both sides.

[AMV8(1day)]

Thanks for the info Tony.

Hey Jared, what is the deck height of the VK56 compared to the VK45?

Got more to say but gotta go.

[Jerminator96]

I've searched and haven't been able to pull any numbers out, but considering I'm going for double the horsepower and E85 I'm thinking I'm going to have to find a considerably larger set that will fit the block and be able to spray a sufficient amount in the smaller window left for direct injection.

 

I was actually wondering about pressure rather than flow rate, but I guess if you give me that and the size of the nozzle I can do the math myself.

[AMV8(1day)]

Still having issues with tracking the info on the stock engine down since there aren't any tuners that I know that have worked with the DD version of this engine yet. I've still gotta get some help figuring out required pressure, flow rate, etc. for not only dealing with direct injection considering they only typically get a fraction of the time to discharge the fuel compared to conventional injection, but E85 requires more fuel for the same bang due to lower potential power production.

[Pete84]

FYI, a couple of years ago, those IRL engines were being sold off considerably cheaper than the quoted price.

McMeekin Bros back east were not privy to the Nissan IRL clearinghouse, so bought an Aroura IRL engine for a similar price. They put it in a 240SX.

 

They move at over 200mph at Bonneville if I'm not mistaken...

 

The CORR Racing Trucks were running the 5.6 at 8200+ rpms and making a gob more power than the stated goals above (other than rpm range). Basically forged pistons and isky bumpsticks. They used the factory sump that whole first season. Some nice OEM engineering there!

 

What bellhousing do those Nissan and Aroura IRL motors use? Proprietary or a more standard one?

 

Any idea of what the lifespan of the 5.6 engine was in those race conditions? To get that sort of power from a nearly stock motor is incredible!! The rods and crank must be something else!