RV8 Power

[Poledriver]

OK. I'm trying to put together an RV8 engine with the hopes of acheiving 325+ BHP.
I'm hoping some of you guys can let me know which of the current ancilliaries which I have are the weakest links and need to be changed:-
Heads are from JE engineering, large valves and ported.
Cam is from same source, JE 101
Inlet trumpets are shortened with bellmouth.
Larger plenum and throttle body (Jaguar)
"Flapper" type AFM (Jaguar)
Jaguar injectors.
Early type ECU with fuel delivery adjuster.

I'd prefer not to veer away from N/A if possible.

I hope you don't "say chuck it all", but if needs must.................

[Graham]

I'd drop Jamie at castle race engines an e-mail ( hes starting back at work now after loosing his wife).

He built my original 5ltr serpentine race motor that pushed out 330+ on a stock plenum ( blended trumpet base) standard TB and stock injectors no AFM coupled to an emerald ecu, using a locked distributor as the crank sensor and spark distributor. ( advance contoled by the ecu within the range of the dissy sweep). when we went to wasted spark we found about another 30bhp.

I'd say your restriction is probably in the early efi system JE heads and cam should be up to it..

[itsallyellow]

Another recomendation for Jamie here. Grahams engine is very good!

Mike

[Poledriver]

Thanks guys, I'll contact him! I was thinking in terms of emerald alreday, may be able to do something more with plenum too!

[Markh]

itsallyellow said:

Another recomendation for Jamie here. Grahams engine is very good!

Mike

And me top bloke

[teamHOLDENracing]

Graham said:

I'd drop Jamie at castle race engines an e-mail ( hes starting back at work now after loosing his wife).

He built my original 5ltr serpentine race motor that pushed out 330+ on a stock plenum ( blended trumpet base) standard TB and stock injectors no AFM coupled to an emerald ecu, using a locked distributor as the crank sensor and spark distributor. ( advance contoled by the ecu within the range of the dissy sweep). when we went to wasted spark we found about another 30bhp.

I'd say your restriction is probably in the early efi system JE heads and cam should be up to it..

Surely not Graham. 330+ bhp plus another 30bhp from wasted spark would have put you at at least 360bhp. Wasn't the class limitr 350bhp....?

[350Matt]

fit a Ø45mm trumpet base or...

Ideally junk the rover based plenum and intake as its rather restrictive.

and yes Emerald all the way it will make tuning it all far far easier

Matt

[rev-erend]

You did not mention capacity ..

You are not really gonna see 325+ unless you have at least 4.8 litres..

[Poledriver]

OK. I'm going to be looking at 5.0-5.2 litres. Emerald ECU with no AFM. Twin throttle boddied plenum, already got the 45mm short flared trumpets.
Any suggestions for cam? (currently JE101) Don't want it too intractible for the road, but not worried about a little lumpiness at tickover.
Are there any gains to be made with lightening the flywheel?
With the larger capacity and power, should I be looking at slightly larger diameter pipes in the exhaust manifold (everyone says leave them as they are for smaller capacity and up to 250BHP but I've not seen much info for higher power/capacity)

Can anyone recommend a good company who will offer life insurance for TVR drivers?

[macdeb]

Big up for Jamie from me. Nice guy, dedicated and no bullst. Keen on 'piper cams' which worked well.

[Graham]

teamHOLDENracing said:

Surely not Graham. 330+ bhp plus another 30bhp from wasted spark would have put you at at least 360bhp. Wasn't the class limitr 350bhp....?

<lol> but using the ignition timing, its easy to move the peek power back down. but obviously when tuning it initially we go for max power... when we went to Throttle bodies we managed to get a peak of 378, which we then fiddled around with trumpets and timing to get to the 300/ton at the wheels which was easier to police than the 350/tom flywheel figure...

Interestingly the power curve wasnt dropping off at the end, and was only restricted by our rev limit, with a steel crank the power with the Throttle bodies on looks like it would have made over 400bhp.... with the plenum it was dropping dramatically after it hit peak...




Yes Jamie has a good relationship with piper and they did some special cams for the Racer FOC

[Poledriver]

Hi guys,
I've still been honing down my plans to build a quick engine. I wonder if you can let me know if there are any serious holes in my plans to build a 325BHP + RV 8 engine.
I currently have a TVR 'Wedge' with a JE developments. 4.5 litre engine fitted with their JE101 cam and sports heads (larger valves, ported and polished). This has been measured at 250-255BHP.
My plan is to get a 'Coscast' block, fitted with a 'Real Steel' 5 litre stroker crankshaft/con-rod/piston kit, existing heads and cam, 42mm flared trumpets and a custom made plenum-chamber/dual throttle body unit.
The plenum is actually 2 standard units, cut in half, with the two standard throttle bodies, one on each side. This will be set up slightly differently to standard in that I will have no MAF unit, only one of the throttle pots will be used and I have got a (hopefully) unique linkage which will cause the primary throttle body to open on it's own up to about one 1/3 rd of it's travel before the secondary throttle body starts to open. When the primary TB reaches maximum opening the secondary one will also reach max opening. Hopefully thie will give a smooth and controlable initial pull away, together with the potential of economy, coupled with a substantial increase in power at larger throttle openings.
I am currently looking at the 'Emerald' ECU, but could be persuaded to use Megasquirt if the price is right.
Questions I have:-
Do you have any experience of the JE 'Sports' heads versus the 'Merlin' heads?
Is the JE 101 cam right for the job?
Does the Coscast block/5 litre stroker kit option work?
Will my plenum system work?
Am I right in looking at the Emerald ECU?
Am I looking at 325+ BHP with this installation?

Cheers

KARL

PS ETA I need to get this on the road for Easter!

Edited by Poledriver on Monday 5th January 01:26

Edited by Poledriver on Monday 5th January 01:56

[Brummmie]

I had a 4.6 unit in a 400se made 297bhp. It was a budget build using a block and pistons from a burnout Range (4.0), i stroked it with a stock 4.6 crank, larger inlet/exhaust valves and blended the bowls. I had a few chips to use so went to the rollers and settled on a 4.3 non cat Griff chip. I was using hot wire, cam from Real Steel. But i swapped the engine into a Chimaera i later purchased and it went sooo much better, only change was exhaust, so the Wedge stuff HAD to be restrictive, maybe i've missed it, but if you dont look here you will suffer. HTH.

[rev-erend]

Questions..

Is the Coscast using top hats..

The pistons & heads will need to be either of known cc or calculated to find your c/r ..

10 or 10.5 to 1 would probably be best for bhp.

Pistons probably need pocketing

The inlet sounds interesting but without pictures it's inpossible to say .. an even air distribution across all cylinders is what is needed. 2 converging airflows at 90 degrees to each out may not work well ..

[Poledriver]

rev-erend said:

Questions..

Is the Coscast using top hats..

The pistons & heads will need to be either of known cc or calculated to find your c/r ..

10 or 10.5 to 1 would probably be best for bhp.

Pistons probably need pocketing

The inlet sounds interesting but without pictures it's inpossible to say .. an even air distribution across all cylinders is what is needed. 2 converging airflows at 90 degrees to each out may not work well ..

Not top hat, this design is supposed to get around the problems exhibited with the original castings.
I'm going to have to check the combustion chamber volume but the pistons are classed as 'high compression' (getting more details from Real Steel)
The plenum/throttle bodies will be 'siamesed', i.e. throttle bodies on opposite sides, facing each other. After some consultation it appears that one bank of cylinders may receive a weaker mixture than the other if I try my approach, so I'll probably keep a normal one-to-one linkage so they both open at the same rate!

[spend]

Seems a lot of effort and expense, but then you are keeping a 'woolly' hydraulic cam?

[Poledriver]

spend said:

Seems a lot of effort and expense, but then you are keeping a 'woolly' hydraulic cam?

All options are still open, there are just so many different ideas and opinions at the moment so I am still gathering data!

[GreenV8S]

I can't point you to the person who did it, but I thought the siamese plenum idea had been tried and found no better than the original. Putting the two throttle bodies on the same side so the flow is distributed better to the front and rear cylinders seems to be the way to go.

[v8ian]

The question was asked earlier in this thread," will a lightened flywheel meke more power?" No, it will promote a quicker reving engine, but not produce more power,
I am getting ready to build a new engine so this is an interesting thread,
one thought at the moment is using a 4.6 as a base, and longer rods, possibly 6.2-6.25", ultralight pistons, possibly skirtless bike pistons, may produce a slappy engine, but its not a daily, so it wont be a problem, I will opt for a LOT of static compression, 13.1++, TVR challenge heads and a stupid mechanical cam, Emerald ECU, Im looking for 350/60 hp ,
not a lover of Megasquirt, I dont know of anybody who has managed to get one to work correctly for any length of time, I have also seen a Real steel 5.0 crank snap the nose off, and that was without giving the engine a hard time,

[Poledriver]

v8ian said:

The question was asked earlier in this thread," will a lightened flywheel meke more power?" No, it will promote a quicker reving engine, but not produce more power,
I am getting ready to build a new engine so this is an interesting thread,
one thought at the moment is using a 4.6 as a base, and longer rods, possibly 6.2-6.25", ultralight pistons, possibly skirtless bike pistons, may produce a slappy engine, but its not a daily, so it wont be a problem, I will opt for a LOT of static compression, 13.1++, TVR challenge heads and a stupid mechanical cam, Emerald ECU, Im looking for 350/60 hp ,
not a lover of Megasquirt, I dont know of anybody who has managed to get one to work correctly for any length of time, I have also seen a Real steel 5.0 crank snap the nose off, and that was without giving the engine a hard time,

I didn't actually ask if lightening the flywheel would give more power, it is merely a lump of metal!
Interesting comment about the Real Steel crank, looks like one to avoid! I have e-mailed them to ask what they recommend for maximum revs/power/torque with the stroker crank, I've not had a reply yet!