Engine capacity question

[vpulsar]

Hello all and firstly let me apologize if I'm asking this question in the wrong section, But I'm new to this forum and couldn't find a better location, My question to you is how far can you re -bore the 280 engine if necessary ?, And is the a top spec 280 bottom end capable of handling 300 bhp @ the wheels ?.

Once I buy a good 260 I'd rather keep the engine bay looking some what standardish if at all pos, If not then I'll look at other engine options to get what I'm after.



Rob

 

[SeanDezart]

My question to you is how far can you re -bore the 280 engine if necessary ?

There are those that say 89mm - after that, if you want more ccs, change the crakshaft.

And is the a top spec 280 bottom end capable of handling 300 bhp @ the wheels ?

Yes, but not for the road - an engine producing that needs frequent striping down - it's more for competition use.

Are you considering a turbo or not ?

Have you tried a Z with 'just' 250bhp ?

 

[zedhead260]

I think 300bhp "at the wheels" would need a bloody great turbo........ so therefore it wouldn't look very standard under the bonnet.

 

[vpulsar]

Are you considering a turbo or not ?

Have you tried a Z with 'just' 250bhp ?

I've just finished building a 500 bhp turbo car and don't really fancy going down that route again, It's a lot of work to control the extra heat created by the turbo and inlet temps, Plus I can't be doing with the hassle of changing all the wiring to accommodate a new ECU to control the fuel injection and boost.

I do quite fancy fitting a V8 if not just for the sound effect , And no I've not driven a 250bhp one my old one was less than that I'd of thought but it did run tripple webbers, But I'd of thought it would feel pretty slow compared to my 500bhp pulsar .

But if I can build a very free revving 6 pot with instant throttle response then that might suffice, I was looking a re diff options over in the states last night and they do some fantastic stuff, I never realized just how much stuff is available for these cars .


Rob

 

[ben240z]

My question to you is how far can you re -bore the 280 engine if necessary ?, And is the a top spec 280 bottom end capable of handling 300 bhp @ the wheels ?.

Rob

Finding a block that will take an 89mm piston and still leave sufficient wall thickness to keep the block from flexing is going to be your problem.
A genuine 300hp at the wheels from a normally aspirated (bored and stroked to 3.1) 280 engine is optamistic.
Seans comment on rebuilding the engine on a regular basis I have to disagree with. A well put together engine using the correct parts will be good for thousands of miles, but that is my opinion based on the engines that I have built in the past and the current one I am running now.
For a daily driver I personally would go for a short stroke 2.8 giving around 2.6 capacity(depending on whether you go oversize on the bore) with mapped ignition and fueling. This will give you a strong engine that spins up quickly and due to the mapping will be happy driving round town as well as stretching it's legs on some open roads.
The problem with striving for 300hp at the wheels on a road car is what transmission are you going to use. Unless you use a straight cut gearbox you will lose approx 25% power from flywheel to wheels.
Putting 300hp onto the road through the rear wheels only will involve loss of traction and some serious rubber. I can spin the rears on my race car changing into 4th and I am running the softest hillclimb slicks that are available and they are 10 inch wide.
The Z engine produces immense amounts of torque and if mapped/cammed and fueled correctly this will happen at low revs. 200 ft/lb of torque at 2000rpm. Who needs big bhp
Just my thoughts and no doubt they will be shot down in flames.
Buy your Z and enjoy it but dont strive for the ambitious hp figures that are banded about by the modern cars. The Z doesnt need them

 

[status]

Well put Ben,some of us r running 3.1 engines and throttle bodies,try and have a ride in one of our cars,you will soon realise you dont need 300bhp,i live essex- herts borders,you r welcome to come round some time and i will take you for a blast but bring a spare pair of underpants

 

[vpulsar]

Buy your Z and enjoy it but don't strive for the ambitious hp figures that are banded about by the modern cars. The Z doesn't need them

I appreciate the effort you put into writing that reply and you made some good points, But 200ft lb's isn't going to set the world a lite is it , My car has 443 ft lb's at the moment but I do understand and am not aiming for silly power figures from a Z car, Transmission wise I'm sure someone like Quaife must make a stronger gear set ?, I have a Quaife in my current car.

But I'm leaning towards a Rover V8 which is both light and torque and has several tried and trusted transmission options available, But I will leave what ever car I buy alone for the summer so I can access the situation and get used to driving a rear wheel drive car again.


Rob

 

[ben240z]

I appreciate the effort you put into writing that reply and you made some good points, But 200ft lb's isn't going to set the world a lite is it , My car has 443 ft lb's at the moment but I do understand and am not aiming for silly power figures from a Z car, Transmission wise I'm sure someone like Quaife must make a stronger gear set ?, I have a Quaife in my current car.

But I'm leaning towards a Rover V8 which is both light and torque and has several tried and trusted transmission options available, But I will leave what ever car I buy alone for the summer so I can access the situation and get used to driving a rear wheel drive car again.


Rob

200 ft lb at 2000rpm rising to 270 at 4000 and then staying flat to 8000. It sets my rear tyres alight.90 ft lb of peak torque per litre from a normally aspirated motor is what you can expect I do take your point about your figures but then that is turbo power and torque.
If you want to see what a 240z will do in fairly standard mode that look at rob gaskin on a trackday in his 240. He leaves the modded tripple carbed in his rear view mirror and gives steve francis in the v8 a good run for his money.
My advise is do not try to compare a Z with your previous turbo performance. have a real good look around at various cars and set ups and then build what you want/ can use and afford. You will never get the money back that you spend on a Z once you start modding it.
Please dont take this response as a negative one.Ben

 

[vpulsar]

Well put Ben,some of us r running 3.1 engines and throttle bodies,try and have a ride in one of our cars,you will soon realise you dont need 300bhp,i live essex- herts borders,you r welcome to come round some time and i will take you for a blast but bring a spare pair of underpants

Thanks for the kind offer mate, I'd of taken you up on that if I still lived in Hampshire but we moved to Aberdeenshire 4 years ago and it would be a bit of a trek lol.

Like I said I wont do anything to hasty, I'll live with the car for the summer and think about all my options and take advice from you guys, I'd be made not to listen to the people with experience something I wish I had done with my old car 20 years ago .


Rob

 

[vpulsar]

You will never get the money back that you spend on a Z once you start modding it.

LOL, Tell me about it, I'm just about to loose 40k at least by selling my pulsar for 15k, But it's not about the money is it , I wont be spending 60k on another old car thats for sure.

And Ben I never take other people's opinions as negative mate, Every body has their own and I respect that .

I think a budget of around 25k in total is realistic for this project and it will be something I don't plan to sell anyway, Well not until I'm really old anyway lol, Which isn't that far off I suppose .

I do intend to track this car as well a drag race it to, I'm not expecting the high tens that my pulsar is capable of though, My old 260z clocked 14.7 at the pod all those years ago, So I'll be happy with high 12's .



ROb

 

[zedhead260]

Rob, I think the Chevy V8 may be the better option for you. They are pretty much a bolt in conversion these days and you'll get both the power and the torque you require.

Another interesting project to keep an eye on

 

[vpulsar]

Rob, I think the Chevy V8 may be the better option for you. They are pretty much a bolt in conversion these days and you'll get both the power and the torque you require.

I was looking into that option and was what I was trying to do with my old car 20 years ago, I had bought the 4 bolt main engine ready to fit but unfortunately for me it was around the same time as the big recession hit and I ended up loosing my job/house and just about everything else I owned at the time including my projects .

Maybe it's a case of I can at last finish what I started 20 years ago.



Rob

 

[Ian Patmore]

vpulsar,
Some good info here..here is my two pence worth as I am one of the owners here with one of the "upper echelons" of N/A L engines/development.

There are a few companies (worldwide) who can go more than 89mm bore (with confidence), and with stroke, giving a 3.1, 3.2, 3.3, and I think a 3.4, but this takes an awful, awful lot of block/crank/piston/rod work, and an awful lot of expertise. And of course a large lump/trailer full of cash. And to be honest, going to the extra expense, only gets you a few extra horse or torques, which you aren't going to notice. And from my impression, the most anyone has managed to get out of a superdoper L series (n/a) is in the 330-350bhp area, but that is crossing the wire into race engines, which are more (are) difficult to live with on the street. So if you want 300bhp at the wheels, as suggested, go turbo or V8.

As Sean said have you tried a Z with 250hp...I have been is Status's Z with around this figure, and it goes like stink, tracktable, and generally a great all round Z of joy

As touched on briefly by Ben, gearbox and all other different areas need upgraded to try and keep the horses/torques where they should be... there are some quick Z's out there without going to the enth degree of bore/stroke

Good luck and keep us posted on where you go with your engine choice.
Regards
Ian

 

[vpulsar]

Good luck and keep us posted on where you go with your engine choice.
Regards
Ian

Cheers Ian will do mate, But I think I'm getting a bit a head of myself at the moment because I haven't found a good en yet , Or even started looking properly.

I need to sell or break up my Pulsar to found this purchase so it might be a month or two before I get hold of enough cash, We just bought a new shape WRX STi type UK as well so I'm sure the running costs will be a bit of a shock lol.



Rob

 

[SKiddell]

Ben I think your absolutely spot on, particularly when you say

My advise is do not try to compare a Z with your previous turbo performance

NA power delivery is totally differant, many a turbo car has been embarassed by a well setup 240 around a track simply because they come off boost and then can't spool up quick enough....its not how big the number is its the area under the graph that counts.

My old 260z clocked 14.7 at the pod all those years ago, So I'll be happy with high 12's .

with the greatest of respect Just about any 240/260 with a half decent engine and triples will do 14's ......12 seconds on the other hand is a differant story all together, there are only a handfull of "road cars" world wide (normally aspirated L series) that can do it without resorting to cement filled blocks, slicks, stripping the car down or resorting to downhill drag strips and even then conditions need to be right.
Respectfully to put an NA Z get into the 12's and it still be drivable on the road takes a great deal of skill, time and money....no boost controller to twiddle with so you have to resort to "real" tuning

 

[vpulsar]

with the greatest of respect Just about any 240/260 with a half decent engine and triples will do 14's ......12 seconds on the other hand is a differant story all together, there are only a handfull of "road cars" world wide (normally aspirated L series) that can do it without resorting to cement filled blocks, slicks, stripping the car down or resorting to downhill drag strips and even then conditions need to be right.
Respectfully to put an NA Z get into the 12's and it still be drivable on the road takes a great deal of skill, time and money....no boost controller to twiddle with so you have to resort to "real" tuning

Great reply mate, Like I said it's been 20 years since I owned my last car and that was the heavier 2+2 not a 2 seater, To be honest I don't think I'll use the straight 6 engine as their are plenty of other options out there, I do want to keep it N/A though I've had enough of all that laggy turbo nonsense , I want to get back to some instant response even if it's not as fast as my old turbo car, I doubt much is what with it having 517 bhp/443ft lb's and only weighing in at 1240kg .

Anyway I want this car to produce power easily and not be some highly stressed race engine, Does anybody know off hand the difference in weight between the standard 6 pot and a small block chevy ?.

But I still fancy the later rover V8 engines but with a holley fitted and not injection.

Just the sound track of a V8 must be worth the effort surely .



Rob

 

[twoforty]

"laggy turbo nonsense"

 

[260Z TT]

What's this laggy turbo nonsense then? You only get that with large or poorly selected turbos.
My 260 with twin T3's will pull respectable from 35 in top gear, and strongly from 2500rpm.
Also weighed the car on cornerweight scales at work, comes in at 1200 kilos ready to roll, full interior and stereo.
Mark.

 

[JakTheRuby]

A V8 with Holley carbs is gonna sound the part for sure. Won't really be a Z any more though. I guess it just depends what you want the car for (daily driver or just for trackdays/drag racing). A 240 in the right hands is a seriously nimble sports car to start with. At Japfest recently a pretty stock 240 gave an awful lot of problems to an Evo 8 with everything on it. With some beefy cams on that six and a fiddle with the suspention I think you'd be genuinely surprised with what it can do. Good luck with whatever you go for though. You're in good company here for advice. These guys have pretty much tried and tested all manner of combinations in that engine bay. Just make sure you keep us updated and post some pics when you can.

 

[twoforty]

What's this laggy turbo nonsense then? You only get that with large or poorly selected turbos.
My 260 with twin T3's will pull respectable from 35 in top gear, and strongly from 2500rpm.
Also weighed the car on cornerweight scales at work, comes in at 1200 kilos ready to roll, full interior and stereo.
Mark.

Yep spot on...no lag on my car.....but with high lift cam on the old NA N42 it felt laggy as hell. Only poorly matched turbos on low compression engines give turbo's a bad name. I'd never go back to NA.