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V8 7's how do they perform?
donut - 23/1/06 at 08:07 AM

Going to be a long time until i can go V8 but it's something i really want to do at some stage so have kinda decided to start collecting bits as they pop up. Before i do though i would like to know from those who have them how they drive. Do they wheel spin all the time, are they particularly scary or very docile.

Any advice would be gratefully received.

[img][/img]


smart51 - 23/1/06 at 08:18 AM

The Westfield Seight has a very similar 0-60 time quoted for it as the hayabusa engined car. Similar performance then, except the V8 has a higher top speed.

I used to know someone with an Seight. He said it would wheelspin in the dry in all 6 gears. If you pushed him, he would reduce it to the first 4 gears. He had the shift light permenantly set to 4000 as it was too scary to go over that. It was a nice car though.


Bouldy - 23/1/06 at 09:10 AM

Andy as soon as i get mine back i will let you know.

we will have to meet up either at a show or somewhere else so you can have a drive and try it for yourself.


Scotty - 23/1/06 at 09:23 AM

mmmmmm
interesting question
i wanted the sound of a v8
not overly interested on the speed issue thing (really!) as i have a half decent tin top
but will watch this post


smart51 - 23/1/06 at 09:30 AM

You don't have to have power to have a V8. Rover V8s came is various sizes from 2.5 to 3.9 litres (I think). Some American V8s produce barely 150 BHP, something a goos 2 litre I4 European engine can manage. Even with a small V8, you get the sound that you're looking for.


donut - 23/1/06 at 09:49 AM

Sorry i should have put more info on the 1st post. i'm not interested in a fire breathing monster engine, a std 130-150bhp engine will be enough as there is enough torque to pull a forest down! [img][/img]It's the noise i really want and the torque. It's the torque that worries me the most i guess which i why people say they wheelspin so freely. I have an LSD and larger tyres on the rear shouldn't be a problem. Just cos i have the power doesn't mean i have to use it i guess.

Paul: I'll take you up on your offer of a drive!!! [img][/img]


nick205 - 23/1/06 at 09:53 AM

surely we're overdue a discussion on power vs. torque here aren't we

...by the way Andy, why don't you just give in and build yourself a Cobra kit? I'm sure you can still frequent these pages although people might ask why you run th MK Owner's Club!!!

Cheers
Nick

...see I told you the torque was important

[Edited on 23/1/06 by nick205]


andyw7de - 23/1/06 at 10:00 AM

I used to have a 3.9 V8 Striker that was only used for the track.

It sounded awesome and had great low down torque, but without serious work on the top end it would rev limit itself at about 4500 / 5000 rpm due to the hydraulic tappets.

It aso ate clutches, i ran a standard SD1 5 speed gearbox coupled to a 3.0 capri LSD with 10" soft compound slicks.

Im currently building a GTS W7DE and did consider the V8 again but have gone for a 16v XE. more power for less money

Will miss that noise though


donut - 23/1/06 at 10:04 AM

I did go down the Cobra route but they do cost too much to build. I decided 2 things.

1st: The Sumo although a decent car is not the best likeness for the Cobra and if i'm honest, if i did build a Cobra i would want it to be a decent one like AK, GD, Crendon, Ram etc and they really do cost!! Plus i would rather not build again!

2nd: Someone said once, "never meet your idols" cos they are never what you think they are going to be. I love the Cobra and my heart skips a beat every time i see one thundering past but owning one......dunno. Would it ruin the mistique of the car? I think it might but i will never know for sure unless i buy/build one.

As for power v's torque....who cares, it's the rumble in the jungle that get's me going!! [img][/img]


NS Dev - 23/1/06 at 11:44 AM

Just found my answer to this question that I posted previously (a long time ago!)


"The fact is that you need an engine with a power/torque curve which approximately matches the ability of the wheels to put that torque on the road.

Having loads of torque at low revs is of no practical advantage in a seven because the laws of physics (and therefore the traction that can be obtained) mean that the maximum torque that can be transmitted to the road via the driven wheels is very low.

As wheel rpm increases, you can transmit progressively more power (same TORQUE!) through the driven wheels.

What you really need is an engine with a very wide power/torque band and a very big rev range.....................but then that's what we are all trying to achieve!!

As was pointed out, all the reasonably powerful engines can spin the wheels of a 7 with relative ease, the difference is that most of them have bigger rev ranges and their torque tends to fall from the bottom of the power band to the top, hence whilst accellerating, the likelihood of breaking traction decreases with speed through each gear.

Here the v8 becomes a problem as it's rev range (for the cheaper end of the market!) is limited, and in each gear the torque tends to build to a peak and then fall off again (remember that for any engine, the power and torque curves (in bhp and ftlb) cross at 5250 rpm, how does that compare to peak rpm, if it's near the limiter then all your driving will be on the increasing part of the torque curve!!)

The next problem is that with that limited rev range, the time until the next gear is short, and then the problem is repeated all over again!!!

Now contrast that to a revvy 4 cyl or 6 cyl engine (I know this is not scientifically correct, but I am referring to commonly available engines, not the "ideal world"!) where (for my Vauxhall XE for example) the working rev range is basically 5000rpm to 7500rpm. Torque peaks at around 5000rpm (as it does for most roughly square bore-stroke 4 cyl engines) and then falls all the way to 7500rpm, but the power peaks at 6500rpm ish. This means that if you can get away from a standing start fairly cleanly, traction should increase through the rev range, whereas with the v8 it will actually decrease.

Horses for courses though..............v8's sound awesome!!!!!!!!!"


MikeR - 23/1/06 at 12:08 PM

but a thraped v6 also sounds pretty good as well!

(used to love the sound of mates v6 mondeo when it was reved - sounded very angry!)


smart51 - 23/1/06 at 12:24 PM

I have to say that there is a lot of credibility in the sentiment expressed here that speed is not the important thing but the sound of the engine. It is not a bad thing to want to cruise around in an interesting car listening to the low down burble of a short shifted V8. If that is what the car is for then talk of torque curves and power is meaningless. It would be a different story if you were building a road rocket but not everyone wants the same thing from there car


NS Dev - 23/1/06 at 01:10 PM

very true! hence my last line above!!!


smart51 - 23/1/06 at 01:16 PM

Actually, NSDev, from reading your post about area under the torque curve and wider torque curves are better, I was expecting you to recommend a bike engine!


froggy - 23/1/06 at 01:39 PM

a lot of problems using rover lumps stems from the low gearing they end up with as the vittese sdi had a 2.8 diff on 60 series 15" wheels compared with most sevens using 3.62 diff or lower, hence why a lot of dax v8,s run 17" wheels to compensate. il have the same trouble with my car but with 4wd should have good traction even if its geared too low. on the plus side you dont have to fret about biulding the car superlight as a bit of lard wont affect the performance one bit

in all honesty its the noise that does it for me, its one of those engines that sounds wether your pottering about or giving it a shoeing!


NS Dev - 23/1/06 at 01:41 PM

Heh heh!!!

No, I have considered it but it's still not ideal!

If you want to know my ideal engine for a seven then here it is!:




can't get a bigger pic but it is an Opel-Cosworth KF V6. 2.5 litre but absolutely miniscule in size, weighs in at 90kg all up which is a nice sort of weight for a 400+ hp engine. (on pneumatic valve springs they were pushing 500hp from 2.5 litres at 14,000rpm but that was not on pump fuel!!!)

Now with wire valve springs and a sensible low rev limit of only 11,000 revs they still push out around 400hp with a nice torque spread as well.!


Johnmor - 23/1/06 at 02:04 PM

I am quite keen to find out peoples assessment of this type of engine in a locost as I am fitting an Alfa v6 in a Viento.
The alfa has approx 190 BHP and about 190lbs torque, but , having a over square stroke is very free revving.
I know the Rover has more Torque at low revs, but in standard form has a lot less bhp and is not a free revving as the Alfa.
The engine is through a type 9 and then a 3.62 LSD. I am hoping for long gears as I have driven An Alfa 24v and it revs to over 7000 easy. This allows the driver to use the higher gears earlier and then it pulls all the way.
The alfa 164 will slip into 3rd at 20mph and then go all the way to over 100mph with continous accelaration.


I dont want a skittish tail happy car just a flexible, strong pulling, howling,country road, smile enducing machine, that all.


akumabito - 23/1/06 at 02:11 PM

BMW V8... got the noise, got the power. Relatively cheap too...


donut - 23/1/06 at 02:38 PM

quote:

I have to say that there is a lot of credibility in the sentiment expressed here that speed is not the important thing but the sound of the engine. It is not a bad thing to want to cruise around in an interesting car listening to the low down burble of a short shifted V8. If that is what the car is for then talk of torque curves and power is meaningless. It would be a different story if you were building a road rocket but not everyone wants the same thing from there car

This is exactly what i'm thinking. Couldn't have put it better myself.


froggy - 23/1/06 at 03:27 PM

its unlikely that you would buy an early rover engine now as most sd1 ended up as donors for kits and hot rods. a early nineties range rover or disco would be the donor nowadays and from 94 the engine improved a huge amount and a stock 3.9 will give gwtting on for 200 at the flywheel. its popularity is more to do with its longevity than design as its got its faults with poor oil system and main bearing location on the pre 1990 engines but its well supported for parts and performance stuff .as a road car engine its great but i wish it would rev a bit better too


donut - 23/1/06 at 03:38 PM

When are we going to see some pics of your monster then froggy?


froggy - 23/1/06 at 03:53 PM

how do you get them onto the screen? ive got some pics of my bec kitten in the archive but no clue how to set one as my avatar. send me an email and i can send some but im struggling to put them on here!.id get more done if i wasnt on here so much ive put my weber set up on ebay and bought r1 carbs after seeing rwd kurts car. ive built a coulpe of kittens before ,one crossflow and then a fiat twink, this one will have a good start with martins chassis under it. ive still got that spare engine you know


donut - 23/1/06 at 04:01 PM

U2U sent [img][/img]


Agriv8 - 23/1/06 at 05:23 PM

My tuppenth worth.

Regarding the tourque yup baggs of it, too much to be honest, an engine that can shift 2 tone of range rover up a 1 in 4 grassy bank is going to light up the rear wheels of a seven.

This is my excuse for pilling on a few pounds over christmas as I need a the rear end weight.

As froggy points out a lot of the DAX boys run 17s and 3.14lsd diff on sticky 225 / 245's on the rear ( thus the rather expensive image wheels to sit them on ). one with 330 bhp.

The other option is be cautious of the loud peddal ( roundabouts while wet especially ). Dailly driver is Passat TDI so low down grunt is what I am used to.

but as people point out I am after the tail happy v8 burble.

Agriv8


mark chandler - 23/1/06 at 05:54 PM

Rover V8's tend to feel lazy due to the standard cams, the are suited to heavy cars/landrovers etc.

stick in a hybrid 218 cam and it will rev freely to 6000 rpm.

I,ve go a 4.6 under my bench, with a hybrid 228 cam, it revs madly and pushes out around 300 bhp but I am building a blade engined locost because in theory it will be just as fast but handle as well !

If you do go rover V8, try and buy a late 3.9 classic with serpentine front end, much better oil pump.

Avoid early p6 engines, rope seals and as most donors are range rover elso ensure its 9.35:1 comp ratio (number stamped on block near the dipstick).

Regards Mark


froggy - 23/1/06 at 07:44 PM

impressive! hows the lag though?


MrTom - 23/1/06 at 08:02 PM

I'd been thinking about doing a v8 locost. You know, Because I'm an American. But I couldn't fit it with T-Tops, so I gave up on that plan.

I picked up an all aluminium DOHC 4.6 ford v8 for $500US. And I got the car it was installed in for free. It's a shame to just use the engine, because the car is in such nice shape, but I really have no use for a 4300lb landyacht like that.

I think just about any v8 would throw off the weight balance, the smallest v8 I've found over here for a reasonable price is the Ford DOHC 3.4 in the SHO Taurus. And it's still probably far too heavy to use in a car you want to handle well.


02GF74 - 23/1/06 at 08:04 PM

quote:
Originally posted by smart51
You don't have to have power to have a V8. Rover V8s came is various sizes from 2.5 to 3.9 litres (I think). Some American V8s produce barely 150 BHP, something a goos 2 litre I4 European engine can manage. Even with a small V8, you get the sound that you're looking for.


River v8 came in 1 size, 3.5 l. Land/Range Rover v8 varied from 3.5 through to 4.6.

It is big lazy relatively light all alloy engine, not particularly powerful but can be tuned up at reasonable cost ; bear in mind there is twice as many heads etc.


NS Dev - 23/1/06 at 08:20 PM

quote:
Originally posted by MrTom
I'd been thinking about doing a v8 locost. You know, Because I'm an American. But I couldn't fit it with T-Tops, so I gave up on that plan.

I picked up an all aluminium DOHC 4.6 ford v8 for $500US. And I got the car it was installed in for free. It's a shame to just use the engine, because the car is in such nice shape, but I really have no use for a 4300lb landyacht like that.

I think just about any v8 would throw off the weight balance, the smallest v8 I've found over here for a reasonable price is the Ford DOHC 3.4 in the SHO Taurus. And it's still probably far too heavy to use in a car you want to handle well.


Despite my earlier post which no-doubt came over as anti-v8, the rover all alloy v8 is pretty light, certainly weight is not the big issue, more bulk per hp and lack of revs.


NS Dev - 23/1/06 at 08:23 PM

quote:
Originally posted by Johnmor
I am quite keen to find out peoples assessment of this type of engine in a locost as I am fitting an Alfa v6 in a Viento.
The alfa has approx 190 BHP and about 190lbs torque, but , having a over square stroke is very free revving.
I know the Rover has more Torque at low revs, but in standard form has a lot less bhp and is not a free revving as the Alfa.
The engine is through a type 9 and then a 3.62 LSD. I am hoping for long gears as I have driven An Alfa 24v and it revs to over 7000 easy. This allows the driver to use the higher gears earlier and then it pulls all the way.
The alfa 164 will slip into 3rd at 20mph and then go all the way to over 100mph with continous accelaration.


I dont want a skittish tail happy car just a flexible, strong pulling, howling,country road, smile enducing machine, that all.


Hmmmmmmmmmmm, scottish roads and v6 viento...................rather a nice combination methinks!!!!!

That engine should make for a lovely combination! Don't overgear it though, remember that over 100mph in a 7 is a pretty horrible affair for any length of time, it's the 40-100mph "sweet spot" that these cars live for!


Johnmor - 23/1/06 at 08:34 PM

Your right about the max speed, I hope to have a geared max of about 135mph depending on tyres, so i think that should give a pretty good 3rd and 4th gear performance, as you say, dont want to go too fast , I just want to get there quick.

Long summer nights and some West coast roads are my main objective.


MrTom - 23/1/06 at 08:36 PM

quote:
Originally posted by NS Dev

Despite my earlier post which no-doubt came over as anti-v8, the rover all alloy v8 is pretty light, certainly weight is not the big issue, more bulk per hp and lack of revs.


Well I'm always keen on power to weight ratio, and 280bhp out of a 600lb engine just doesnt seem that impressive. (600lbs is what ford says their 4.6 crate engine weighs)

But it revs to 6 grand. 6 is pretty good for a v8.

Dont get me wrong, I'm very pro V8. But I'm also pro 'go really fast and be able to turn while you're doing it'


taxi - 23/1/06 at 08:52 PM

Absolutely wonderful I would think, nice and lazy up to 3000 rpm and then just magnificent up to red line at 5500 rpm. Plus that noise. Standard sd1 3.5 engine on su
carbs 150 bhp, 3.5 Vitesse with efi 190bhp.


Simon - 23/1/06 at 09:36 PM

Donut,

It's fine, though I "only" have a standard SD1 motor (approx 155bhp) - really do need a 3.14 diff (see my other thread!!).

I've not noticed any squirming, though obviously am taking it easy (ish) as I've only done a couple of hundred miles.

Sound on a closed throttle is fab

ATB

Simon

[Edited on 23/1/06 by Simon]


donut - 23/1/06 at 10:10 PM

Simon, have you got an LSD fitted or is that one of the reasons for the diff change?

Also how's the insurance?

[Edited on 23/1/06 by donut]


Simon - 23/1/06 at 10:31 PM

Andy,

No, no LSD though may think about it in the future, main reason for change is 1st gear is useless, and could probably get away with just using 3rd, 4th and 5th.

At the moment 70mph is 3375 rpm, with 3.14 diff it would be about 2600 rpm and with a 2.83 - just under 2500.

Will aid my fuel consumption too!!!!!!

ATB

Simon

[Edited on 23/1/06 by Simon]


omega 24 v6 - 23/1/06 at 10:33 PM

What about the beatifully engineered V8 RS4 (i think thats what it was called) engine that was on show at autosport. There was one in a metallic grey seven which was documented as 770bhp per ton. Awesome piece of kit.


froggy - 23/1/06 at 10:57 PM

not really any bad responses so far about the old lump then?
the common opinion is you need to run a 3.15 diff with 15" wheels to use all five gears normally and try and find a post 94 engine if possible to get it to rev over 5000rpm regularly without wearing the bottom end out and perhaps a ten gallon tank to soften the blow of single figure mpg a lot of rover powered cars capri escort etc can get 20 ish mpg without driving like a nun,my old avenger with efi did about that but around 12mpg footdown but that was 1000kg easily . most se7ens with the rover in are around the 700-750kg mark .


Volvorsport - 23/1/06 at 10:57 PM

the other way of looking at it - is that your tyres can only produce grip with the weight(force) that is applied to them .

so lots of torque , multiplied by ratios at low rpm , will always spin tyres.

and in a light car , the problem is worsened in that tyres for this weight of car , cost loads .

hmm , i might have to think about my own gearing !!


Simon - 23/1/06 at 11:01 PM

I'm using 17" wheels, but a 40 profile tyre so not that different to rolling radius of Sierra.

ATB

Simon


froggy - 23/1/06 at 11:29 PM

with those wheels a 3.15 will be cock on for a stock engine. gearing should be exactly the same as the v8 sd1 which had a 3.08 diff and 15" on 60 series tyres


Simon - 23/1/06 at 11:45 PM

Yeah, and if I can get it to rev to 6000, I'll only need one gear (2nd) to get to 62mph - should do wonders for time!!

ATB

Simon


jonno - 24/1/06 at 12:15 AM

he he look at this http://boardroom.wscc.co.uk/cgi-bin/ikonboard.cgi?s=1436fb26292c7397d83c5af767dd0b83;act=ST;f=8;t=36538


carcentric - 24/1/06 at 01:12 AM

My childhood dream was a Lotus 7 with a Ford 60 V8 - they're known over here as "flathead" engines (pre-OHV). They're not very big or heavy (despite being all iron), but they have a GREAT sound!

Did any cars in the UK use a similar 1950s engine?


Simon - 24/1/06 at 09:01 PM

Only thing that would have been close was the Ford V8 Pilot, apart from Jag, RR Aston and a couple of expensive low volume (though more modern engines compared to flathead), cars here had (for the most part) puny 850cc (51 cu.in.) to 1300 engines (and about 25 bhp)

ATB

Simon


steve m - 24/1/06 at 09:09 PM

My car wheel spins in every gear (in the wet)

bloody undriveable in the wet

[Edited on 24/1/06 by steve m]


MikeR - 24/1/06 at 09:12 PM

do you take it to church often? Sounds like it needs it with all that sin!


steve m - 24/1/06 at 09:19 PM

fixed


mattes - 2/4/06 at 10:28 PM

quote:
Originally posted by smart51
You don't have to have power to have a V8. Rover V8s came is various sizes from 2.5 to 3.9 litres (I think). Some American V8s produce barely 150 BHP, something a goos 2 litre I4 European engine can manage. Even with a small V8, you get the sound that you're looking for.

Right on. I have a Westfield that began life as a SEiGHT. GREAT SOUND, Good Torque, adequate power -- at least I thought so until I put the car on a dyno and saw only 140 hp at the rear wheels! I eventually broke the engine and replaced it with a Honda S2000. Much faster now -- though only about 75 lbs. lighter. Power aside, the biggest effect of the engine swap resulted from my stiffening the Westfield frame forward of the firewall when doing the job. YMMV.

Hans