Whilst I'm at the build stage of my car shall I stroke the engine to 5.0L or leave it as a 4.0L? Whichever I choose will have the twin turbos fitted. Is the 4.0L a better road engine, revs more with more driveability or is the 5.0L with the extra torque the way forward?
Anyone had any experience in going from a 4 to 5L motor and is it worth the pain and cost?
Jeff
To stroke or not to stroke? That is the question
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Ian Anderson
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Are you also changing your gearbox?
If not the ratios may not be correct for the extra torque being had at a lower rev range
Ian
If not the ratios may not be correct for the extra torque being had at a lower rev range
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
You will no doubt have more fun with a twin turbo 5.0 as I found out when I changed from a 3.9 TT.
It may of course not be as easy to control.
My set up is based on the TVR 90mm stroke crank with TVR conrods.
However, getting pistons that will give a low enough CR was a problem so I had some Forged items custom made with a deep dish and thick crowns etc. (£900). The alternative is to use Buick heads which have a large combustion chamber.
I'm not too happy with the TVR set up as the rods are too short and inefficient and the pistons rattle as they almost pop out the bottom of the bore at BDC. There is also the stories of the tendancy for the TVR crank to snap so that influences my right foot at times.
There are other options to achieve the 5.0 litres but if I was doing it again I would stay away from the |TVR set up. I did get the crank balanced internally to help reduce possible internal stresses but in any case I did not have the matched weighted TVR front pulley and flywheel.
I believe you will be using twin Janspeed turbos. These will be slow to spin up on a 4.0 lump but probably will be much more responsive on a 5.0 but will still come in with a bang at 4000 RPM.
I use twin Cosworth 4x4 turbos which seem to be ideal for road use.
Regards Denis
It may of course not be as easy to control.
My set up is based on the TVR 90mm stroke crank with TVR conrods.
However, getting pistons that will give a low enough CR was a problem so I had some Forged items custom made with a deep dish and thick crowns etc. (£900). The alternative is to use Buick heads which have a large combustion chamber.
I'm not too happy with the TVR set up as the rods are too short and inefficient and the pistons rattle as they almost pop out the bottom of the bore at BDC. There is also the stories of the tendancy for the TVR crank to snap so that influences my right foot at times.
There are other options to achieve the 5.0 litres but if I was doing it again I would stay away from the |TVR set up. I did get the crank balanced internally to help reduce possible internal stresses but in any case I did not have the matched weighted TVR front pulley and flywheel.
I believe you will be using twin Janspeed turbos. These will be slow to spin up on a 4.0 lump but probably will be much more responsive on a 5.0 but will still come in with a bang at 4000 RPM.
I use twin Cosworth 4x4 turbos which seem to be ideal for road use.
Regards Denis
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!
