Ideas for nitroused v8 rebuild
Discussion
I have been drag racing my fairly standard TVR Chimaera 450 over the last 18 months and have dropped my 1/4 ET from 14.0 to 11.6 with the aid of a pair of sticky tyres, a decent clutch and more and more nitrous oxide.
I want the car to run 10's next year and believe i will need a healthy 300 bhp + another 300 with nitrous.
My poor 105000 mile engine finally gave up a piston with 250 bhp of nitrous being thrown at it and forgetting i hadnt retarded the ignition so i am currently stripping it down ready for a full rebuild.
Its a '98 4.5 ltr Rover v8, crossbolted with 10 bolt big valve heads.
The priority is the drag racing but i will also use the car for pleasure etc on the road but dont mind giving up the smooth idle for higher rpm gains.
All advice on cam, piston choice etc will be gratefully received.
I want the car to run 10's next year and believe i will need a healthy 300 bhp + another 300 with nitrous.
My poor 105000 mile engine finally gave up a piston with 250 bhp of nitrous being thrown at it and forgetting i hadnt retarded the ignition so i am currently stripping it down ready for a full rebuild.
Its a '98 4.5 ltr Rover v8, crossbolted with 10 bolt big valve heads.
The priority is the drag racing but i will also use the car for pleasure etc on the road but dont mind giving up the smooth idle for higher rpm gains.
All advice on cam, piston choice etc will be gratefully received.
have a look over on the wizards of nos forums you will find loads of helpful advice there from the UK's premier nitrous suppliier http://forum.nitrous-advice.org
ringram said:
Usual stuff will apply like 2618 alloy with thick piston crown and ringlands I imagine.
Cams usually have more exhaust duration than standard too. Good luck with it. Interesting to see you run "only" 14 sec std
Oops sorry that should read 13.0 @ 107 without gas but with sticky tyres and a decent clutch.Cams usually have more exhaust duration than standard too. Good luck with it. Interesting to see you run "only" 14 sec std
My best time on gas is 11.63 @ 122.6 but ive had abest terminal over 125.
My aim next year with an engine that can take more gas and a set of Nitrons to help get the power down is to run into the 10's over 130.
Im very aware of the wizards advice being a customer and regular on the forum but am looking for other advice on specific cam profiles or piston designs etc. I want the engine to run quite happily off gas but laughing when on it.
crank the compression up a bit if you are going to run a decent cam, you will need to anyway. Best to get someone to design the whole thing as a unit. compression and pistons will need to suit cam. Also how about getting some decent ported heads while you are at it? What about exhaust dual 2.5"? headers etc?
ringram said:
crank the compression up a bit if you are going to run a decent cam
How does that tie in with NOS? With forced induction you would be looking to reduce the CR, do you need to reduce it with NOS too? (Perhaps not with small amounts, but doubling the power output implies the in-cylinder pressures are going up rather a lot.)Nitrous can work with fairly high CR's but as with forced induction the engine works much better lowering the compression as boost is raised.
Im aiming for around 9:1 so the engine will still perform well NA but will have the ability to take a fairly large hit of gas. Forged pistons will help take the greatly increased cylinder pressures.
Im aiming for around 9:1 so the engine will still perform well NA but will have the ability to take a fairly large hit of gas. Forged pistons will help take the greatly increased cylinder pressures.
rev-erend said:
The engine bay is pretty tight .. so it's a fairly expensive process. Also with the extra weight - you have to get the engine back as far as possible.
Others here like Jellison have done it.
The old Rover lump isn't small though and its wide. I know space is always an issue, wouldn't have thought it was that bad though.Others here like Jellison have done it.
Also with the weight, I'm a bit on the fence with this one, I know everyone loves to quote the 318lbs or whatever it is Google turns up for the RV8's weight, But aren't the latter units heavier and with all the plenium (aluminium whereas composite on the LS1) and such I'm not sure its such a huge difference.
A quick Google says GM quote 450lbs and 490lbs fully dressed including flywheel. That's 223kg.
Also using Google it seems to suggest a dressed RV8 with flywheel weighs 200-230kg.
Either way there's not a lot in it IMO.
I have no idea how complex it is to get it in a TVR. But I've heard of people picking up LS1's for £1500-2000 including ECU. You could easily blow that on rebuilding a Rover.
It would also give the OP plenty of scope if they wanted more in times to come. If they max out the Rover lump now it leaves nowhere but an engine swap if they want more.
dbv8 said:
The LS option makes a lot of sense but i want to retain the cars original engine and push the limits using nitrous.
It would be nice to chase the LS cerbs at the drag strip with a car that stands me at not much more than £10k at present.
It would be nice to chase the LS cerbs at the drag strip with a car that stands me at not much more than £10k at present.
Sounds like a good idea .. go for much more power and the next weakness will start to be a big problem : Gearbox
Drive shafts
Axle
Just get out there and have fun.
The T5 is suprisingly strong in the first 4 gears. I dont get into 5th at the strip but events like fighting torque and the full mile is very tempting.
I will be fitting raceproved driveshafts (about £350) and checking the UJs etc.
I have a set of Nitrons on my dining table as we speak (better than any centrepiece). This was a big investment for me and im hoping the 3-way rears will provide me with the launch traction ive been striving for.
So the ultimate aim next year is a 300 bhp engine + 300 more nitrous.
1/4 mile in 10.9 @ 130+
Mile in 29.9 @ 165
0-60 in 3.0 seconds
0-100 in just over 6
I will be fitting raceproved driveshafts (about £350) and checking the UJs etc.
I have a set of Nitrons on my dining table as we speak (better than any centrepiece). This was a big investment for me and im hoping the 3-way rears will provide me with the launch traction ive been striving for.
So the ultimate aim next year is a 300 bhp engine + 300 more nitrous.
1/4 mile in 10.9 @ 130+
Mile in 29.9 @ 165
0-60 in 3.0 seconds
0-100 in just over 6
Edited by dbv8 on Wednesday 30th September 12:43
300bhp/ton said:
Sounds impressive 
How long do you think the motor will last that highly tuned with a 300 shot?
Assume you are going for full forged internal?
10.99 seconds should be long enough How long do you think the motor will last that highly tuned with a 300 shot?
Assume you are going for full forged internal?
A 300nhp nitrous shot isnt as bad as it sounds. Ive crudely injected upto 250 into mine with no adverse affects when the timing was set correctly.
I sure hope to get a full seasons drag racing next year without too much drama.
Ive decided to invest £500 or whatever inforged pistons (waiting for quotes).
GreenV8S said:
How does that tie in with NOS? With forced induction you would be looking to reduce the CR, do you need to reduce it with NOS too? (Perhaps not with small amounts, but doubling the power output implies the in-cylinder pressures are going up rather a lot.)
NOS intake charge is really cool due to expansion of the gas etc. So you can run higher compression. When she fires off though it will hit hard, hence you need munchy pistons. Makes it nice off the gas as well.FWIW i swapped and LS1 into my offroad truck taking out a 4.6 RV8 THOR in the process
dressed weight the difference was 16kg according to a load cell i borrowed hangin off the engine hoist- can't remember the exact figures.
Size wise the LS1 was something like 5cm taller but narrower, and almost exctly the same length. Found that a RV8 with ZF4HP24 was almost exactly the same length as a LS1 with a 4L60e which was nice.
dressed weight the difference was 16kg according to a load cell i borrowed hangin off the engine hoist- can't remember the exact figures.
Size wise the LS1 was something like 5cm taller but narrower, and almost exctly the same length. Found that a RV8 with ZF4HP24 was almost exactly the same length as a LS1 with a 4L60e which was nice.
pugwash4x4 said:
FWIW i swapped and LS1 into my offroad truck taking out a 4.6 RV8 THOR in the process
dressed weight the difference was 16kg according to a load cell i borrowed hangin off the engine hoist- can't remember the exact figures.
Size wise the LS1 was something like 5cm taller but narrower, and almost exctly the same length. Found that a RV8 with ZF4HP24 was almost exactly the same length as a LS1 with a 4L60e which was nice.
That sounds like an interesting project. Would be interested to know more about it.dressed weight the difference was 16kg according to a load cell i borrowed hangin off the engine hoist- can't remember the exact figures.
Size wise the LS1 was something like 5cm taller but narrower, and almost exctly the same length. Found that a RV8 with ZF4HP24 was almost exactly the same length as a LS1 with a 4L60e which was nice.
I've often thought it'd be fun to try something similar.
How did you beef up the axles?
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