300bhp/ton

You've never been able to respond to any questions I've posed to you or been able to backup any claims you've made with data or references. So I'm not even going to bother responding.

300bhp/ton

Ok assume GM converted the LSx to a DOHC engine using the same block and same ability to be taken out to 427ci or bigger. (This has been done numerous times with other engines).

Same physical size and weight for the most part, a tad taller and wider maybe for the DOHC heads but nothing worth crying over.

Would specific output still be meaningless?

Lsx OHV = stock ~65bhp/litre. Street modified 95bhp/litre
Lsx DOHC - stock ~70-80bhp/litre. Street modifed 114bhp/litre

BTW who cares about production cost. A Mustang has a OHC and is cheaper than OHV GTO or Fbody (when in production).

black_knight

iTrader: (1)

Lies.

black_knight

iTrader: (1)

*clears throat*

YES!

The better engine would be better due to more HP/Lb, more overall HP, and other metrics. HP/L would still be a useless metric. Even a stopped clock gives the right time twice a day.

300bhp/ton

Well you can think what you want, but I'm happy to have an extra 50 even 80lb of weight in a vehicle wieghing 3500lb+ if it has the potental to make sugnificantly more power.

Your metric of HP/lb is pretty pointless. As it means you should go for the engine with the lest weight and most power. I think you'd end up with a motorbike 1200cc engine. They make great hp/lb. But sadly would be rather pathetic in a muscle car.

So who's being more "Ricerish" then?

black_knight

iTrader: (1)

I'd be interested if you could back up that claim about the best HP/lb being a motorbike engine. I doubt that is true.

But if you did, then it's just a matter of putting enough of them in there. (provided they fit)

300bhp/ton

I don't have any weights but comeon seriesouly some of these bike engines make 180bhp stock and capable of over 220bhp with mods. And they are tiny you can pick them up in your arms easy. Very popular with many of the lightweight kit cars and such.


EDIT:
Radical SR8

72° V8 cylinder 2.6-litre
32 valve quad cam Max. Power: 363bhp @ 10,300 rpm
Max. Torque: 200 ft lbs @7,000 rpm
Bore: 81mm
Stroke: 63mm
Compression Ratio: 11.0:1
Weight: 95kg (209lb)

This is a V8 made from 4 motorcycle engines. So I guess a regular motorcylce engine would weigh 50-70lb as this is 4 times the size and only weighs 209lb.

More power than a stock Ls1 and less than half the weight, plus it's really small as well.



BTW - it's an OHC And has pretty good specific output as well.

mattkimsey

GM owned the majority of the company which was 60%.



The LT5 was 602lbs -- the LT1 was 452lbs. Needless to say, that is a big difference mostly because it adds weight to the front of an already front heavy car and it shifts the weight upward. The LT5 also used an aluminum block whereas the LT1 was iron....still it was much heavier. The LT5's weight was right in line with Ford's current 580lb DOHC 4.6. In comparison, the LS1 is flyweight at 390lbs.





In America the Mustang V6 costs $19,410 for the V6 version — that’s £10,600. In other words, £385 less than the cheapest Vauxhall Astra in the UK. Even V8 Mustang costs $24,995 or £13,667 — £1,623 less than the cheapest Ford Mondeo.


In 1991, the ZR1 was making 380hp and it would've dominated a NSX in just about any performance comparison. As far as power, several mags tested the NSX between '91 and '96 and the 1/4 times were between 13.8 and 14.4. They also tested the ZR1 and ran 12.8 - 13.1. The base Vettes between '90 and '95 ran the same times as the same year NSXs. The '96 C4 Vettes with 330hp were as fast as any NSX than has came here. As far as handling, the NSX and C4 are both run A-stock in SCCA and the C4 dominates the class.





Maybe for one that has all the options, but they start about £33000. $44,000 for a base 'Vette + ~10% duty + 5% shipping + 17.5% VAT + ~£3000 to get SVA'd. Total: ~£33,500

MadSpeed

Umm.... Top fuel has nothing to do with what production cars use.. Top Fuel is ALL CUSTOM aftermarket stuff
now If you want to compare Tthat to somthing production you might want to think of prostock

black_knight

iTrader: (1)

So then HP/Lb is a good measure. Glad we're agreed on that.

300bhp/ton

Well the numbers I saw for the LT5 where a lot lower than that. Also that sounds incrediably light for an LT1. I guess that is dry weight without accessories.

And again for the LS1, fully dressed it's well over 400lb.


As I said you CAN NOT directly compare prices.

Items may cost more, but by contrast we are also paid more. So typically one unit of currency will purchase the same amount of goods.

And a new Stang does cost £23-26k here. I was looking at buying one. And in fact its where I found my z/28 as it had been p/x for a new Stang.

The NSX was never ever intended to compeat with the ZR1. Also the ZR1 was massivly expensive for a Corvette compared to a regular C4. Plus the NSX was a special edition, it was just the regular model.

Go and read any proper writeup or report of the NSX and it will always be looked upon as a 911 rival. And in 1991 it certainly had the driver involment and performance to rival a Cerrar 2 and was in the same price category. The ZR-1 was a US only model and not part of the world market. So not meaning any discredit to it, but I wouldn't have thought Honda would have given any real thought to it.

People always seem to forget the latter NSX, not sure why. The early ones where not as fast, they received some updates but looked the same. However the latter ones don't have pop-up head lights. These where the fastest, and to be honest in average hands are a very good match up for even a C6. They are very easy to drive with loads of grip due to mid engine layout.

Handling does not = grip. and never has. Handling is about feel and control. Ayrton Senna sorted the handling out on the car. So if it was good enough for one of the worlds best race drivers then I'm pretty sure it's good enough for me.

Aerton Senna
Maybe for one that has all the options, but they start about £33000. $44,000 for a base 'Vette + ~10% duty + 5% shipping + 17.5% VAT + ~£3000 to get SVA'd. Total: ~£33,500[/QUOTE]
GM offically imports 'x' number and sells them at select GM dealers. But there are lots and lots of private American car importers these retail for ~£45k. But maybe I'll have to look into it. As I do rather fancy a C6.

300bhp/ton

They may be heavily modified but they are all originally based around production engines. Specifically the hemi. So it's easy to base a custom race block off of someone elses design and just refine it.

Actually producing an engine from scratch and developing every component. Know that's a different ball game althogether.

One day it will happen and we will see a large displacement DOHC being used to it's potential. Just sadly not yet.

300bhp/ton

Only if you want a completly meaning less measure, yes.

black_knight

iTrader: (1)

But you just provided an example, meant to prove me wrong, where it was in fact meaningful. Listen, I'm not saying it's the be-all-end-all. You still have to consider overall HP and of course power under the curve. But HP/lb is a provably useful measure and even your own example proved my very point. On exactly what basis are you declaring it meaningless?

And meanwhile you think HP/L is meaningful.

Honestly, step back from whatever it is that is preventing you from thinking about this seriously and use your brain for a second. You seem perfectly able to use it in other circumstances; why not on this topic? Is there something they put in the water over there that makes everyone an HP/L zombie?

Honestly, it is a totally useless and amateurish way of looking at engines.

300bhp/ton

Think about it this way, in a 3000-3500lb vehicle what has a greater affect on performance.

1. An extra 100bhp?
2. 100lb less weight?

Hp/lb in terms of the engine itself is totally pointless in the big picture. An Fbody weighs an average of 3500lb with a 400lb motor. So the weight of the motor only accounts for a little over 25% of the TOTAL vehicle weight. If the engine is made 100lb heavier or lighter it will not have a dramatic affect on the over performance of the vehicle. Nor will it have a massive affect on the bhp/ton ratio either. Althogh the engines own specific hp/lb would have dramatically changed. An extra 100bhp would make a massive difference by comparison.

No if you are talking about a flywieght vehicle weighing only 1320lb, then yeah an extra 100lb will make a bigger difference. But typically such cars don't use such an engine so it's pretty academic.

The only time I can your metric being usuable is if you physically attached the wheels to the engine and said to hell with the rest of the car.

black_knight

iTrader: (1)

It's useful to compare engines to each other. Both horesepower and weight are attributes of engines that affect performance. You can argue about how useful it is. You can point out oddball scenarios where one engine has a slightly worse hp/lb but a much higher overall output (in which case why are you comparing those two engines at all?).

Bottom line is that is does have its uses.

Unlike HP/L. Which is just flat rubbish.

87formy

I'm not sure I have much to contribute here, but it seems like you guys are arguing the same thing. If you can see that horsepower per pound is a good measurement in a lightweight application, then what’s the difference in an f-body? 100 pounds will still affect track times and the handling of the car. I'm not sure why you’re arguing hp/l is a good measurement because it only seems to measure efficiency, instead of overall horsepower for a given weight which seems is more applicable. On the previous page I saw your ls7 example. Sure, it's more efficient to only use 5.0L to make the same horsepower as 7.0 liters, but that makes no difference in anything, weight does. You said in your previous post that it would not make a major difference, but for the sake of going as fast as you can and handling the best it can, then all of the weight matters and 100 pounds off the nose of a car can make a big difference.

I'm not sure if I missed it or not, but why do you think hp/l is a good measurement? Is your reasoning that you can get more horsepower into a smaller space (car)?

Flaminchiten67

Actually its about 11.4 %

mattkimsey

The purchasing power parity is actually closer to 1.5:1. In other words, £1.5 is equal to $1 of purchasing power in the US. This is partly a result of things costing more in the UK - namely property values.

This is kind of irrelavant in a performance comparison. Both cars were made to perform -- neither directly with the other, but the ZR1 is "the king of the hill" as it was named.

I'm on pistonheads.com and one of the importers has Z06s starting at 58,739 and C6 coupes starting at 33,900 -- both prices are on the road.

300bhp/ton

I don't think it's a good measurement as a measure of CARS performance.

Over HP and weight, or rather power to wieght is more important (hence my username).

But in terms of determining what an engine is capable of bhp/litre is very useful. This is not relative to an actual car, just the powerplant.

My point is the engine with the most displacement and the best specific out will be able to produce the most power.

So take two engines with the same displacement (say 7.0 litres) but one has the ability to be 20-25% more specific output, which one will be the most powerful?

Easy, the highest specific output will be. Now in terms of specific output, multivalve engines that can handle high rpms are the most efficent. In otherwords a DOHC unit.

So logically and mathamatically speaking a large displacment DOHC 'should' outperform a 2v OHV engine of the same displacement.

Sadly there are not currently any production engines that meet this creteria. So in it's absense some people seem to think it's impossible, although it has been proven many times.

In an overall package, weight, hp, size and many other factors are all important. But that wasn't the point being made.