High NA, or TT?

[Hogg]

Hey guys,Been a while since Ive posted - havent had any time to put into my VH

Neglecting is over, Im back to being a Nissan head and going to try my best to get the engine done as a hobby project asap!

So, my block is kindof old and Id love to get it bored 1mm over to freshen it up and give it a little more displacement. However other than that, Im curious as to whether I should pour my money into a Very High Compression and Cam system, or a Twin Turbo setup.

Anyone have any opinions or suggestions on where to pickup these parts and/or why I should choose a certain path?

Thanks!Spence

[kingkilburn]

If I had room and money I would go tt. It seems that people are getting really good power gains from little boost on other wise stock engines.

That being said, I want some big cams, a light rotating assembly, and some high comp pistons.

[doctorchee]

QUOTE=Hogg]Hey guys,Been a while since Ive posted - havent had any time to put into my VH

Neglecting is over, Im back to being a Nissan head and going to try my best to get the engine done as a hobby project asap!

So, my block is kindof old and Id love to get it bored 1mm over to freshen it up and give it a little more displacement. However other than that, Im curious as to whether I should pour my money into a Very High Compression and Cam system, or a Twin Turbo setup.

Anyone have any opinions or suggestions on where to pickup these parts and/or why I should choose a certain path?

Thanks!Spence[/QUOTE]

Hi

i am TT 'ing my car. if things goes well, properly 1 month if should be up and running..

perhaps to help you a bit, why not u define your budget and requirement first?

TT has it own advantages and disadvantages. more but less linear power.NA less but more linear power etc

nothing is best. depends what u use it for. eg NA properly better for track. TT better for straights. having define yr requirement, than yr budget? but to me both are ex. unless u are looking at mild NA set up, else for 12.5:1 set up, its won't be cheap also compare to TT.

for TT setup, its really a night mare for pluming all the exhaust, turbo, water intercooler etc... i have been a bit regret for it as the set up takes almost 2 years now..been to several workshop and all people look at the project as a crazy one. but still i will fight and finish it. I am currently both $$ and time exhuasted. but i guess the final result should be worth while for all the effort.

above is whats the feeling going through me when doing my set up. just share with you and hope it helps. think carefully before you commit. i think i have yet to see anyone completed any big VH project fast. all take times and real commitment.

btw, my set up is a bmw318is with VH41 + T04E x 2 + 180degree exhuast + water intercooler + DTA ECU + full roll cage....etc you can find my set up in 1 of the thread here.

would be good to see you TT. so we have more things and pain to share.....haha

NO PAIN NO GLORY. MORE PAIN MORE GLORY.

good luck.

cheers

[Hogg]

Probably trying to build the motor its self for about 3000, and then 2000 or so to make it a 5speed and get it bolted in and running.

This will be a drift and time attack car, it will be dropped into an S13 Coupe if I can ever find a shell :P

Im thinking of putting in Titan Pistons and Crank, but I dont know if those would fit - or even come in the size I need!

[ScottJackson]

turbo, either single or twin. The fact is that the 4.5L engine doesn't have a lot of cubic inches. The only way it'll make a lot of power is with a lot of RPMs. That's never cheap and it's hard on the engine (the stresses increase by the square of the rpm). Turbo is the same as easy displacement. A very high rpm NA engine is more peaky than a turbo engine. If the turbo(s) is/are properly sized with a good wastegate, it won't be laggy. And don't get so hung up about lowering the compression. The cost of custom low comp pistons with balancing and such is far more than a water/meth injection kit. If the tune is good (that's by far the big killer of turbo engines, a bad tune) and you keep it out of detonation, it'll make a LOAD of reliable power for cheap. You can either add 15psi of boost, or build the engine with custom rods/pistons/titanium valves/heavy springs/custom intake.... to make the same amount of power at 13,000rpm. Good luck with that! I say boost unless you plan to race the car in a class that's not allowed.

[qsiguy]

Turbo...and that's all I have to say about that...

[craigztoyz]

can I hear a good debate on Supercharged(not roots, but cintrifical)(spelling?) versus turbo.Differant engines, different things. THIS SWAP THIS SETUP OF VH45 5SPEED IN A Z32, turbo, has F'd up exhaust plumbing and intake plumbing, Supercharged, would drain engine power from the crank, but a lot less plumbing work and from experience Eith the Yamaha 3.2 SHO engine, and V1's with 10all the way up to 22, the power applied so much better with the blower, becasue it was consistant from the getgo, and was a lot more managable. Where as the turbo, suddenly, kicks you in the ***, and Lag is a factor of not using the right spool, etc.....

I can see where a V1 could fit and run off this engine well, and since it is center, and forward, the plumbing should be decent, but it would have to have a liquid to air cooler to cool the heat. right pulley size would mean a bad *** power curve that would be similar to stock, just up a hundred or so. Just looking to hear some input and experience of others. Not trying to say one is better, just looking for input

[Hogg]

Well turbo would be difficult simply because I have no idea what it would take to accomplish!

However with high compression, (14:1) most likely, I would be going for a big upgrade in the crank and pistons, some wicked cams, and the nismo injectors, then hopefully wrap it up with a Nico ECU and other intake and exhaust mods.

If Im looking like an idiot and missing something please tell me now :P

Seriously, I think a high compression - technology based V8 would be insane. I think TVR has a few motors that are NA but close or more than 500hp and less than 7 litres.

[ScottJackson]

Yeah, and F1 cars are what, 2.4L and 750+hp? High rpms costs. No easy way around it. And hp is just a number based on torque and rpm. It does have meaning, but for a street driven car, a 500hp engine that makes that power at 6000rpm is going to feel a lot stronger than one that makes that number at 11,000rpm. High compression is only good to a point. It has diminishing returns. Going from 8:1 to 9:1 is a substantial difference in power. From 13:1 to 14:1 isn't, but your fuel quality requirements will go up. If you can build a custom sheetmetal intake that's properly sized for your displacement and rpm and if you can afford to build the high rev engine, go for it. It would sound awesome. But if you just want good power for less money, turbo is the way to go. There's several good turbocharging basics books. Read and read lots. Honestly, stock compression is relatively high with the VH. If you could get some good size cams for it and port the heads with a custom intake, you'd make some good NA hp. As for blowers, they work. A twin screw would work well. Centrifugals are good if there's absolutely no room for turbo piping. If you're doing it on the cheap, you could possibly adapt a stock 4.6L ford cobra blower onto the VH.

[craigztoyz]

I looked at the roots style on a 04 cobra, looks interesting, but a p.i.t.a.I like the cyntrifical for the ease, and space, starting to think of ending my project that way. Cams, wish we could get some of those aussie's cheap(500$us total) and then N/a would be awsome. My thought is, my Q45 was fast, and quick for a Heavy *** pig of a car. in the Z, (still heavy sob) would be a great improvement with a stick. Should be fun n/a or boost

[mtcookson]

Boost? I say go turbo. Here's my opinion on supercharging and turbocharging. Had a recent discussion about this so am doing a bit of copying and pasting of what I said.

Quote »As far as superchargers go, as an alternative to a turbo setup... I would only go with a screws supercharger if at all possible. If you only have the options for a centrifugal or roots s/c and a turbo setup... the turbo setup will be the most efficient and will offer the most potential. The centrifugal is too peaky (peak boost at redline), roots isn't efficient enough but will offer a lot of low end, whereas the screws is the best of both worlds... very efficient while offering incredible low end boost/power. Still doesn't hold ground to a turbo setup when it comes to peak performance/efficiency from what I've seen, though in most cases the screws will have better low end power (variable turbochargers will completely change this though and have already, though they are still quite expensive and somewhat difficult to get).

---

There are some benefits to the centrifugal and roots superchargers... though not enough of a benefit to use them when other options are available in my opinion.

The centrifugal superchargers are very efficient, under hood temps are generally lower, they are easier to run an aftercooler, but the biggest benefit is they are pretty compact and are generally the easiest to setup. Generally you'll see these setups producing the most peak power but low and mid range power is minimal compared to the other options since they don't produce peak boost till the engine's redline (boost is linear).

The roots supercharger's benefits are very high reliability, inexpensive, readily available, and produce boost very fast for incredible low end power... they are awesome choices for a good performance street car since the majority of a street car's life will be in the low to mid rev range. The downside to them is they are very inefficient as they are not air compressors. They are simply blowers that move more air than the engine can take it causing the air to compress in the intake manifold itself. Eaton's new TVS rotor designs have improved efficiencies to a peak of 76% adiabatic (heat) efficiency on some models, which is quite impressive but the screws is still superior (not to mention the TVS's are new enough that they will be quite expensive and probably hard to get). The original designs will have less than 70% adiabatic efficiencies, larger blowers being closer to 60% (based off of the Eaton models).

Downsides to both the roots and screws superchargers is they are generally mounted directly to the manifold, which means a manifold must be made for your engine to mount it. Mounting them to the manifold causes the other potential issues being that they generally are pretty tall having a supercharger on top of the manifold meaning some setups may require a different hood. The other issue is that they are more difficult to aftercool. Screws superchargers are efficient enough that you can run a bit more boost non-aftercooled compared to the roots which simply means more power. For high boost setups they really need to be aftercooled. This can be done but requires a water aftercooler to be mounted between the manifold and supercharger. Some manifold setups actually allow the aftercooler to be mounted inside the manifold itself, from what I've seen, which will take away from the space issue but are expensive.

Other routes I've seen for mounting the roots and screws superchargers is a "remote mount" setup, where the unit is mounted to the side of the engine with piping going to the intake (just like a turbo or centrifugal supercharger). Now... I'm not positive on this... but I believe in this instance a screws supercharger would work much, much better since it compresses the air. I've seen these setups done with roots superchargers with good results but I would think efficiency would be extremely poor since it has a lot more volume to pump then compress... but like I said I could be wrong.

The roots and screws superchargers are internally lubricated (have their own oil supply, as do most centrifugals) and can be mounted in just about any angle from what I've seen and still lubricate properly (standard horizontal, vertical, 30°, 45°, etc.) which makes it a very possible setup. Doing this would also make it much easier to use an aftercooler, you could use a standard air/air unit. The only downside to this is the units are pretty big and in most setups you would have a hard time mounting one this way as the accessories will likely be in the way. If you don't have a power steering pump or a/c compressor it would be easier to mount most likely.

One last thing to consider is most roots and screws superchargers use at least an 8 rib pulley/belt. I think some might use a 6, but if so it probably is a smaller unit. The more ribs there are the less slip will occur. I would try to run an 8 or better if possible but this does mean custom pulleys if none are made for your vehicle.

One thing to note that turbo charger setups are a lot easier to do when it comes to custom applications than the supercharger routes since most of those require pulley setups which usually means custom machining of various mounting parts. Custom machining for turbo setups generally stays at flanges which are cheap and easy for machinists to do most of the time. Just more to consider.

All of this info is stuff that I've seen over the years of studying different setups so my info may not be absolute 100% but I'm pretty confident on the info.[/quote]

[Mettler]

High compression is a really good way to boost your entire powerband & make your engine incredibly responsive (supercar style), and return amazing fuel economy. The higher compression have, the better fuel economy you'll get... at the expense of having to use high octane fuel all the time, and of course, building your motor to high compression.

It's annoying that I haven't been able to finish cams yet, as they would unlock a healthy amount of HP in NA trim.

As it stands, your best bet would be turbocharging.

Generally you'll see these setups producing the most peak power but low and mid range power is minimal compared to the other options since they don't produce peak boost till the engine's redline (boost is linear).

Has anyone triple overdriven them with a clutching setup that slips to prevent overrevving the compressor, and a pressure relief valve on the plenum? This would grant you a lot quicker ascent to peak boost (by like, 2500rpm kinda thing), and maintain the same linear peak boost right through the rev range.

[mtcookson]

My idea for a centrifugal s/c has always been CVT pulleys. You could have higher overall efficiency than a screws, instant boost like a roots/screws, and have lower temps than a turbo. It could possibly out perform a turbo... possibly.

The only downside is the CVT pulleys would add a bit of weight to the system and would be somewhat difficult to tune correctly most likely.

[SaintlyCharBoy]

The only downside is the CVT pulleys would add a bit of weight to the system and would be somewhat difficult to tune correctly most likely.

I'd imagine the CVT method would be just like changing weights and ramps in a snowmobile or ATV.

If you could put together a package small enough, IE reduce rotating weight, this could be a very viable solution. Excellent idea!

[mtcookson]

Been staring at turbo compressor maps for a while and it dawned on me that even if I were able to do a CVT setup, the compressor maps of the centrifugal s/c's would limit low end boost.

You could most definitely get full boost quicker but it wouldn't be as instantaneous as I originally thought. Basically, if the centrifugal s/c (and turbocharger for that matter) spools up too fast it will surge, which is bad. You can definitely improve the performance of the centrifugal s/c like I said, but it definitely won't have instant boost like the positive displacement units will (roots/screws). Something to keep in mind.

[SSDwellah]

Well turbo would be difficult simply because I have no idea what it would take to accomplish!

However with high compression, (14:1) most likely, I would be going for a big upgrade in the crank and pistons, some wicked cams, and the nismo injectors, then hopefully wrap it up with a Nico ECU and other intake and exhaust mods.

If Im looking like an idiot and missing something please tell me now :P

Seriously, I think a high compression - technology based V8 would be insane. I think TVR has a few motors that are NA but close or more than 500hp and less than 7 litres.

If you really want to go NA, figure out how they got ~600HP/~450ft lbs in the R391... I'll save you a little bit of time. It was a naturally aspirated 5.0L V8 (VRH50A, 4997cc, DOHC 90* V8 based of of VRH35L/Z series twin-turbo motors, except N/A)

If someone invested the time and research on how to less expensively get these motors to 5.0L, then it would benefit both the N/A and FI guys. Pus whoever sold the kits/services would have a bigger market. Very high compressions is obviously only feasible for the N/A guys (at least when you are running octane and not ethanol, methanol, or diesel), so your market on a high CR piston and ring kit would be smaller.

[Mettler]

There's a genuine NISMO headgasket set for the VH41DE in the 2001 NISMO catalogue (the last year in which they are listed in there), and it has 96mm diameter stated, and t=0.6mm.

If memory serves me right, the VRH50A also runs a 96mm bore... so I was considering whether this particular race motor is the closest to a JDM VH41DE on that basis... and whether this headgasket is the one for the race motor, and if the VH41DE deck pattern is the same as on the race motor.

It bears further investigation, but it's nigh on impossible to get any info out of Nissan Japan.

[Hogg]

Id really like to know for sure if the VH block can be modified to fit Titan VK56DE Pistons and Crank?

This would be where all my money is dumped - I really am a Nismo head and would love to make something thats a representative of it.

Something outrageous - but with lots of custom bits in order to save cost and increase knowledge and skills. etc etc.

Low compression VK56DE pistons for Turbo-Titans, with a Titan Crankshaft would be incredible, and then plus a turbo would make it a monster... Id be down for something like that.

Drift Q45? Chalk one up

[Hogg]

If it proves to be too not work out, Ill just bore out my VH45DE and get some oversized pistons, have the crank balanced, heads redone, cams, and then a big single turbo or two decent sized ones?

Spence

[Bart]

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Modified by Bart at 8:19 AM 2/6/2008

[Carl H]

holy crap are those twin gt3076rs?

[Hogg]

Thats sweet man, what exactly is that going into?

I was thinking of doing two turbos as well - buy some decent either used Garret Rs, or something like that - produce some crazy numbers... Its the tuning Im worried about!

[Bart]

hey Carl, yep your exacly rightHogg, its going into an Australian car, an LJ Torana, (LJ is the model) Mettler would know about them as these were exported to NZ in the seventies when they were built.

[Mettler]

Bart that's lookin badass!!

Just a Q tho, howcome you're highmounting the turbos? There's plenty of room for them forward of the front wheels!

What are you doing with the rear end to stiffen it up? I thought the Torana only has a half-chassis & a weak live rear axle setup... have you got something special in mind?

On my flatmate's sunbird he's considering eventually going to an IRS setup.

[T45]

Come to think of it, I bored mine out to 94mm with the pistons from Safety Mfg and I used a Stone headgasket kit and although I bored it to 94 I still had about 2mm of bore before the ring on the gasket.

I got it from bap-geon but i googled stone and didn't find anything.

[tmorgan4]

Come to think of it, I bored mine out to 94mm with the pistons from Safety Mfg and I used a Stone headgasket kit and although I bored it to 94 I still had about 2mm of bore before the ring on the gasket.

I got it from bap-geon but i googled stone and didn't find anything.

I've got this running through my head all the time. Mine's bored out the same as yours, and I wasn't smart enough to double check the head gasket didn't hang over.

[Bart]

Mettler you’re correct in there’s plenty of room up front for the turbos but the exhaust pipe would have had to go somewhere, either under the cross member (too low) or under the guard, but having a 4 inch dump pipe going down to 3 inch, even the 3 inch would have hit the wheel when turned full lock.The Torana has a full sub frame/chassis front to back, the Sunbird had a half for some silly reason but you can tell your mate he can buy a chassis connector to stiffen the LH don’t know if it will fit a UC Sunbird.The diff is out of the V8 VN Commodore which has held together when I had the RB30t in it for the last few years.

Sorry to hijack this thread but basically my point is go for turbo, but don’t go too big, I just looked at what the SR20 guys were using but of course used 2 turbos, think of the VH as 2 SR20’s, my turbos will support 1000hp and lag wont be too bad, but then im not aiming at 1000hp as that’s pretty ridicules for the street in a 1060kg or 2300 pound car. And if you make up your exhaust manifold do it in 3mm wall mild steel/steam pipe bends or if stainless you should go 321 grade but that will cost you an arm and a pace maker and your left testicle, very expensive but I believe they are fairly available in the US so may be cheaper than here in Aus where it seems only the air craft maintenance/fabricators supply them.