300bhp/ton

Cool, I'd just love to see a manufacturer make a large cc DOHC engine just to see what it could do. Maybe a single plain V8 based off the Evo 2.0 block but bored/stroked to 6.0 litre capcity. I think it'd probably be one hell of an engine n/a let alone 200bhp/litre abilty as a production engine with a turbocharger.

But I guess we'll never see it.

Ta, it's sort of a goal. Was going to try and do it with the TR7 (sig) as it only weighs like 1150kg. But the old Rover V8 is a bit pricey to get the kind of power I needed. So onwards with the LS1 in the Z28?

Z28 = ~1600kg so 300 x 1.6 = 480bhp target bhp. Guess I need to start modding a bit more as the Euro Z28's offically have 288bhp

chuntington101

300, you mean like what power tech have done with 2 busa engines????

yeah would be nice with two evo engines, but you would only see 2.3/4 per engine using evo blocks! you cant bore them much!

still 840bhp per bank and you would have one nice 4.8 ltr twin turbo!

chris.

Big-DEN

Where we were on the DOHC vs OHC is we shrunk it down to packaging size, weight and complexity, and ease of maintenance.

We didnt' care what the internal architecture did, as long as it performed the job.

The problem was some "small" DOHC 4.6L for example is physically as large as a big block package which can hold to right around 600 Cubic inches.

I can only imagine the physical enormity of a 7.7L 12 Cyllinder DOHC motor.

DavidNJ

There are several 6L DOHC V12s in supercars (Enzo, Carrera GT, etc.) and luxury cars (BMW 760).

MadBill

Not to mention the 4 valve/4 cam 8.0 + L. BBC-based Batten, the 16 L. Batten-based Norwood V-12 and the 900 c.i. (14.75 L.) Shubeck marine V-8...

SmokeShow99SS

iTrader: (2)

I was always under the impression that 4 valve DOHC engines made good power under pressure. (Turbos, Supercharger, etc) Any examples of high power N/A DOHC motors

chuntington101

well the GM red top used to make 300bhp in race/very fast road form! thats from a 2.0ltr!!!!!!

Honda 2.0 Vtech is pushing 220bhp stock in japan!

Chris.

and link for thoes DOHC V12???

300bhp/ton

Yeah in the 4 cylinder arena you've got engines like the Honda V-tech, 2.0 and 240bhp (Honda S2000), also the Rover K-Series produced 230bhp from 1.8 litres and Caterham & X-Power also had a few 2.0 Litre blocks with 250bhp. These where all production engines so had to meet certainl noise and emissons controls (inc having cats and so forth).

As already mentioned the Evo FQ 400 with 400bhp STOCK from a 2.0 Turbo.

Then there's the TVR V12 7.7 litre 880bhp, and they also produce a 4.5 V8 with 440bhp and a 4.0 S6 with 406bhp all pretty good specific outputs. These are all n/a.

Aston Martin has a 6.0 DOHC V12 which produces 525bhp as FULL emissions legal production engine. An earlier variant of this was used in the Ford GT90 concept vehicle it was supposed to have quad turbos but Ford never hooked them up as they didn't think the Jaguar XJ220 platform that the car was built on would handle the power. I migth be wrong here as it a few years ago but I think the V12 produced something like 700bhp n/a and a heck of a lot more with the blowers hooked up. (if not it was something similar, I remeber reading a few articles about it, probably still got them in box some where...)

Then there's the Ferrari engines, lots of very good examples.

racer7088

The problem with most NA N valve DOHC engines is that they are very small. They would indeed have much more power if they were larger but they are generally much smaller due to packaging problems. As has been said the LSx is already in the 7 liter rage from the factory and there are no DOHC V8s that size. If there were they would be very scary!

chuntington101

what about MB's 6.3 ltr? its bigger than a stroked LS2 and can probably be taken out to 7.0ltr!

Chris.

racer7088

It might be a good candidate but it's not that big as is! We have 7.5 liter stroked LS2s. Still I bet you're right that it could be very fast.

DavidNJ

One reason there are no &l 4-valve DOHC is there is not really any demand. What manufacturer needs an efficient, gas, NA, 700hp engine? What driveline would it have? Where would it run?

What HP to road race Corvettes run? Not 700. And for drag racing, you get into also sorts of stuff to add on that makes it irrelevant.

Maybe the question is why the emphasis is on 500hp street cars instead of 2500# street cars. Could CF, magnesium, aluminum, etc. be used to bring a Corvette down 600#? Would 450hp, 2500# Corvette be better than the current one? It wouldn't tax the limits of all the other components as much.

chuntington101

it will be even quicker when they bolt a supercharger on there

Chris

chuntington101

david, i agree, but i can exsplane why thye dont! its cost and demand.

the Euro suspersaloons are really big over here and have been for a while! the class leaders for a good 5 years was the BMW m5 with its 400bhp 5.0ltr V8. it was a great car!

but then MB (i think) came out with 500 bhp nd BMW went of acchaced them down with the new M5. 500bhp used to be supercar teratory and now sallons are running the same.

now supercars have to be running 600bhp to be anything!

as for weight, well most people dont care about how much their car weighs just what you get with it! why do you think there are soooo many SUV type veichles that have never even seen off road? so car amnufacturres put more and more stuff in which needs more and more power from the engine. you get where im going!

an example is the "old" golf r32 vs the mark 1 golf gti on paper they had identical power to weight. but the gti won the race!!!!!

thanks Chris.

MrDude_1

iTrader: (4)

thats what the main benifit of the C5 Z06 was, and one of the benifits of the C6 Z06...

go look at the spec sheets.... they went pretty far for weight reduction on the C5... they went CRAZY on the C6....

Sparetire

I fully agree on the wieght thing. So does Gordon Murray BTW.

However, not all DOHC V engines are so bad size-wise. I hear the 'UZ Toyota Engines(4L V8) are very tiny and of course they can make some psycho power too. They fit in Miatas. Thats pretty impressive when you think about it. LS1s are a tight fit into a Miata. Ford concluded that their OHC duratec V6 engines would not really work in that app. Go Toyo.

Thats the best way to go IMHO. BMWs new motors rock, but they are really focusing too much on wringing their motor out up top and being hightech. The M5 does make lots of high rev torque (also known as HP), but it needs a supercomputer to make it work. And the car is a pig. A very expensive one. I could live in that engine bay. BMW has really got the use of high revs and the associated awesome gearing abilities down pat. They have down better than the Japanese even. Now they need to see about making the car an appropriate weight and size. When you think high winding engine with aggresive gearing, you dont imagine a car that weighs more than a "pushrod dinosaur" and makes confetti of brake compnents and track tires.

IMO the big advantages of OHC are not really in the abilities of the car when your talking about V engines. Look at it from the perspective of the people making the car: You can design and then produce a very complex block that has the cam in it, where the valve train is part of both the heads and block, or you can just have a cast Iron lump with a couple flat decks and coolant and oil passages. No cam bearings. No big hole right where the intake mani will be. No pushrod areas. Its just a hell of a lot easier to design and make a OHC motor. Similarly, you just have the cams and such over the intake and exsaust passages in the head on an OHC. The pushrod has to work around the valve train a lot more. Just think about how they get the intake manifold to work around the pushrods. On the OHC motor you dont worry about that. You just bolt a manifold on the side of thing. And I really dont understand why people think OHC is so complex versus pushrods. Its not. IMO its simpler. My head (4g63) has a valves, springs, rockers, retainers, keepers, cams seals, guides, lifters two cam sprokets and timing belt with a tensioner and some pulleys. The pushrod has all that, but one cam comecting to it all (through holes in the head and block) via pushrods. Thats another 16 components right there. Not to mention that the cam is quite a bit more complex.

Basicly, pushrods (which are newer than OHC) are a awesome and complex way to save space and weight. But they have drawbacks. Those drawbacks have been pretty much eliminated for GM because they have it all down to a science. I doubt any other car maker can make an awesome pushrod motor as efficiently as GM. Not even Dodge. Ford gave up years ago.

UofMN

iTrader: (1)

Just surprised no one has brought up the 32 valve 5.7L that GM built from 1990 to 1995. Sure it was ridiculussly expensive but cramming 32 valves under that hood is still impressive. My only thought is why didn't it make more HP. 405 hp does not seem like that much, considering a LS2 makes that. Can anyone explain why this engine was not in the same hp range as some of the foriegners????

Thanks
UofMn (graduated and finally a JOB!!!!!!!)

300bhp/ton

Yeah but the thing to remeber is this was what 15 years ago+ when Lotus where working on it.

The LT1 was still fairly new and it only managed 275bhp so 385 and then 405bhp from a production engine of the same capacity was a massive leap forward.

Plus GM restricted development towards the end of the project, I think Lotus had one which produced well over 550bhp at one point as did the company in the US also doing research/development on them (can't remember who it was). Also remembering that many supercars of that era where only producing ~280bhp, 405bhp truly was impressive.

Also you have to remember the LSx engines where a whole new breed and in OHV terms a major step forwards for a production emissions legal engine. And where not even on the design board some 15+ years ago.

2000zrocks

[QUOTE=300bhp/ton]Yeah but the thing to remeber is this was what 15 years ago+ when Lotus where working on it.

those engines(lt5) were built and developed (i believe) by mercury marine here in wisconsin.

300bhp/ton

[QUOTE=2000zrocks]There was a co development. Lotus Engineering did most of the early work and stayed with the project to the end. Mercury Marine worked along side but seperatly.

If memory serves GM had a part ownership of Lotus Engineering back.