Spec me an engine rebuild for nitrous abuse.

[dbv8]

I have been drag racing my fairly standard 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 so i am currently stripping it down ready for a full rebuild.

All advice on cam, piston choice etc will be gratefully received.

[deetes]

Supercharged LS? must be worth a try.

Jellison did the LS, so it definitely goes in the Chim.

[dbv8]

deetes said:

Supercharged LS? must be worth a try.

Jellison did the LS, so it definitely goes in the Chim.

Be nice but out of my budget.
I want to keep the Rover v8 too. Ive been a fan for 22 years.

[clive f]

the man you need to talk to is Mike, aka boostedls1

[slideways]

clive f said:

the man you need to talk to is Mike, aka boostedls1

+1

[dbv8]

I intend to have a chat with Mike next week but am afraid he will be out of my price range! I want to do most of the work myself and am looking for advice on parts to buy and work that would be worth putting some hours in such as exhaust porting etc.
Besides im too far up North i think, unless there is a cheap courier that would ship the block assembly to Boosted then back with new pistons, bearings and balanced. Like i say i will get some advice and maybe a quote next week.

otherwise im still wanting ideas and technical advice.

[Boosted LS1]

Funnily enough Palletforce ship engines for about £60 on a next day service, door to door. You just strap it down to a pallet and they'll do the rest.

http://www.palletforce.com/

[350Matt]

I'd take a look on the V8 forum;

http://www.v8forum.co.uk/

as there's a few guys who have managed to get Chevy rods and pistons to fit. And the thing here is Nascar bits often come up on the Yankee 'bay as the parts are replaced when they are out of 'life' not when they've failed.

[dbv8]

I got the worst piston out this weekend and the bores etc dont look too bad.
See pics in this thread.... http://www.pistonheads.com/gassing/topic.asp?h=0&a...

On a big budget cut i could just replace the 2 damaged pistons (number 1 suffered from some debris dropping in the inlet trumpet) and fit a set of fresh rings. But would i need to rebalance the engine?
I could sort the heads and have it all bolted back together and running in a few weeks.
Even the cam and followers look like new despite the 13000 miles since i bought the car.

Or do i spend a couple of grand or more??? and go for it properly.... decisions decisions.

[rev-erend]

From memory - forged pistons are the way to go with NO2.

[dbv8]

rev-erend said:

From memory - forged pistons are the way to go with NO2.

Forged pistons would be nice for peace of mind but are really only required if mistakes are made. ie not retarding the ignition and getting detonation and a nitrous explosion
According to the guru himself ie Trevor (the Wizard of Nos) the cast pistons should easily withstand the cylinder pressures produced from running upto 300 bhp of nitrous.

I will be fitting an uprated ecu with switchable maps to make sure everything is in order an idiot proof for next years racing. Emerald or link G4 or similar.

[jhbarford]

Do you run your nitrous with multi-point injection? I too have been experimenting with the stuff and have changed my system to a simpler single injector, however I have a spare set of trumpets with base that has a aet on Highpower Systems injectors with both fuel and nitrous hoses which I am happy to give away if you can use them.

I am visiting friends oop north next weekend, if you're interested I'd be happy to bring it with me.

Jon

[Blown2CV]

Supercharged Sp6 from power? They had a yellow chimmy with just that engine in it when I went there on sat. Bit off-piste I admit. Failing that, John Eales can't be far away from the price of one of those... oh hang on you said rebuild not new engine!

[dbv8]

jhbarford said:

Do you run your nitrous with multi-point injection? I too have been experimenting with the stuff and have changed my system to a simpler single injector, however I have a spare set of trumpets with base that has a aet on Highpower Systems injectors with both fuel and nitrous hoses which I am happy to give away if you can use them.

I am visiting friends oop north next weekend, if you're interested I'd be happy to bring it with me.

Jon

Ive experimented quite a bit too. I originally ran just 1 crossfire injector ar the inlet elbow then 2, then i fitted 2 crossfires into the flared part of the plenum.
Yes thanks i would like to try the set up you have.
Whereabouts oop north are you coming? I could come meet you maybe.
Im in Barrow and can get to the M6 in 1/2 hour or so.

[GreenV8S]

dbv8 said:

Ive experimented quite a bit too. I originally ran just 1 crossfire injector ar the inlet elbow then 2, then i fitted 2 crossfires into the flared part of the plenum.
Yes thanks i would like to try the set up you have.
Whereabouts oop north are you coming? I could come meet you maybe.
Im in Barrow and can get to the M6 in 1/2 hour or so.

Is the distribution critical? Perhaps not if you're injecting 'wet', although I would have thought even then it was pretty important. I would have thought it was quite difficult to get even distribution by injecting into the plenum. (I run upstream fuelling on mine, but the blower does a good job of evaporating and mixing it in with the charge.)

[spend]

I would have thought 'as late as possible' would maximize the benefits of the 'cooling' on expansion properties of the gas. Far more significantly from nitrous than water or fuel being added into the incoming air?

Then again if you injected it into the combustion chamber you may well force charge out of the inlet back into the port?

[dbv8]

At power levels upto 150bhp i reckon the distribution is fine and any small discrepances can be tolerated by a 4.5 ltr v8.
I am wanting to squeeze as much as 300 bhp from my bitrous system next year so i need to get the distribution as even as possible.

[wooly350i]

what about lightening or balancing the flywheel, shorten and flare the trumpets, put a higher lift cam in it, enlarge the ports on the heads and possibly get them skimmed to raise the compression (would recommend speaking to someone to get the best results from this)

[Slow M]

dbv8 said:

rev-erend said:

From memory - forged pistons are the way to go with NO2.

Forged pistons would be nice for peace of mind but are really only required if mistakes are made. ie not retarding the ignition and getting detonation and a nitrous explosion
According to the guru himself ie Trevor (the Wizard of Nos) the cast pistons should easily withstand the cylinder pressures produced from running upto 300 bhp of nitrous.

I will be fitting an uprated ecu with switchable maps to make sure everything is in order an idiot proof for next years racing. Emerald or link G4 or similar.

I'm no wizard but the logic here escapes me. You'll be running the engine's base BHP PLUS 300 additional. What you're running through each combustion chamber are BTUs. You'll be dramatically increasing the thermal load on the pistons. I'd go with Forged ones and even find heavier rather than lighter ones. Also, you may want to consider switching to a high volume oil pump and spraying the underside of the pistons for additional cooling.
From my reading, some people switch rings(?) to a different type for nitrous. No idea what type or what difference though.
B

[dbv8]

It was suggested that good cast pistons for the RV8 can take a lot more abuse than people give credit but i have already decided that a set of fotged pistons is worth the extra expense.
As for rings i believe that its simply a matter of having enough ring gap.
Not sure on design yet but i will check when purchasing the pistons as they come with rings.