Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[2woody]

I'll pitch in and say that at 300BHP, provided it's built right, it'll not eat itself.

The main problem with the GM 54 degree V6 is that the thermostat opens at too high at temperature ( for emissions reasons ). That makes the oil very short-lived and effects the big end bearings. With a decent mass coolant temperature, the engine will live fine at that sort of power rating.

Staying natasp, the power curve is going to be a VERY sporty shape to achieve that power rating. Going forced induction may be a more sensible way, as that usually gives the bottom end a lighter load than a natasp of the same power.

Don't forget that the 3-litre is basically a Vauxhall "red-top" with two extra cylinders.

Swindon Race engines used to sell motorsport 54 degree engines with 400 BHP. I have a spec sheet somewhere.

I certainly wouldn't change the bottom end rotating weight at all - especially the con. rods or pistons. This engine is a very strange design in that its a V6, but with 6 crankpins. That would be a recipe for disaster - the balancing recipe will be pretty unique and not want to be vexed.

So. Cams and compression to match, together with a bespoke inlet system and aftermarket injectio will get your power demand. Budget £5k for this.

[feeutfo]

Interesting project, with a common sense approach by the owner for once.

Is there any scope to strengthen the bottom end? Or it is just a case of rebuilding with a  new bottom end and starting a fresh...?

[2woody]

certainly start afresh, thereafter its all down to oil supply. So, a good clean supply of cool oil is the secret, which means a different cooler and better hose routing. And of course a coolant mass temperature which won't fry the oil.

[cem_devecioglu]

I'll pitch in and say that at 300BHP, provided it's built right, it'll not eat itself.

The main problem with the GM 54 degree V6 is that the thermostat opens at too high at temperature ( for emissions reasons ). That makes the oil very short-lived and effects the big end bearings. With a decent mass coolant temperature, the engine will live fine at that sort of power rating.

Staying natasp, the power curve is going to be a VERY sporty shape to achieve that power rating. Going forced induction may be a more sensible way, as that usually gives the bottom end a lighter load than a natasp of the same power.

Don't forget that the 3-litre is basically a Vauxhall "red-top" with two extra cylinders.

Swindon Race engines used to sell motorsport 54 degree engines with 400 BHP. I have a spec sheet somewhere.

I certainly wouldn't change the bottom end rotating weight at all - especially the con. rods or pistons. This engine is a very strange design in that its a V6, but with 6 crankpins. That would be a recipe for disaster - the balancing recipe will be pretty unique and not want to be vexed.

So. Cams and compression to match, together with a bespoke inlet system and aftermarket injectio will get your power demand. Budget £5k for this.

without forged setup which is quite important..
 
I think 5k£ is an underestimate.. unless you use second hand parts.. only a good supercharger will cost one third to half of it..
 
I know some modding enthusiasts here..  which have deep pockets.. generally the estimated budgets go more than double even without bang..

[Kevin Wood]

Consider that a C20XE will make 200BHP+ all day long on standard internals, hot cams, some porting and decent induction and exhaust so I wouldn't be surprised if the V6 would make pro-rata 300BHP with similar reliability. More so if the 3.2 is used, which has greater capacity and a stronger crank.

In a 650kg car it won't get abuse for long periods either. You'll run out of road.

[cem_devecioglu]

I did some search..
 
and found this
 
http://www.seriouswheels.com/cars/top-2005-Lotus-Sport-Exige.htm
 
most powerful v6 as 2woody mention.. but there is a detail.. they need to be built every 5k miles
 
seems like same subject discussed many times over the net
"Lotus did do a NA race version with 400bhp, but needs a rebuild every 5000miles "
 
from
http://www.opelaus.com/forums/archive/index.php/t-28328.html

 
 

[Vitaliy]

...... and the 54 degree GM V6 is the right package size......

Maybe true, but if my memory serves me well then Renault is the same degree v6.
And I am mentioning this engine only due to the fact that when choosing something reliable no one will think renault.
To be fair it has a very small problem with coilpack, but if its going to be used with custom ecu one can use different coils from different car make.

[markrnorton]

Thanks for all the replies

A bottom end rebuild is a certainty. Top end will get cams and re-worked heads.
as for cooling, idont know much about the oil system, so i will look at this in more detail at some point, water cooling - i know somebody who builds custom rads, so thats an easy sort. the rest of the ssyetm will be simplified and thermostat removed. A controlled electric water pump will regulate flow and temp ( i have done this many times before)

I have built alot of engines before, i know alot of machine shops and i do 'custom' build ups (from non conventional parts- as long as they will work/fit once machined), so i have a few ideas already.
individual throttle butterflies may help breathing, and i will be using MAP sensor rather than the MAF.

Thanks again for the replies to the thread , all good.

I'll start a build thread soon, as most of the parts i am using are Omega and then modified somewhat.

[markrnorton]

...... and the 54 degree GM V6 is the right package size......

Maybe true, but if my memory serves me well then Renault is the same degree v6.
And I am mentioning this engine only due to the fact that when choosing something reliable no one will think renault.
To be fair it has a very small problem with coilpack, but if its going to be used with custom ecu one can use different coils from different car make.

that engine was considered, but mating it to a RWD gearbox can prove a headache. I went through alot of V6 engines !

[cem_devecioglu]

...... and the 54 degree GM V6 is the right package size......

Maybe true, but if my memory serves me well then Renault is the same degree v6.
And I am mentioning this engine only due to the fact that when choosing something reliable no one will think renault.
To be fair it has a very small problem with coilpack, but if its going to be used with custom ecu one can use different coils from different car make.

I'm using race developed K4M daily,  very robust engine.. and never had any problems except alternator..

[aaronjb]

A controlled electric water pump will regulate flow and temp ( i have done this many times before)

I'd be interested in picking your brains on that 

It's going to be good to see what you come up with FWIW I'm with 2woody & Kevin on the potential.. and it should go like the proverbial off a shiny shovel in the Ginetta!

[markrnorton]

A controlled electric water pump will regulate flow and temp ( i have done this many times before)

I'd be interested in picking your brains on that 

It's going to be good to see what you come up with FWIW I'm with 2woody & Kevin on the potential.. and it should go like the proverbial off a shiny shovel in the Ginetta!

The electric pumps and controllers are great. They control flow against temp. At start up minimal flow (remember no thermostat) so engine warms up quick, once warm, the pump speeds up flow to maintain temp. Also used with electric fan set-up.
Has the benefit of running after the engine is switched off, coupled with the electric fan, gives engine time to cool and reduces hot spots.

I think 300hp is a realistic target for the v6 without spending shed loads. Main costs will be cams and rods. I think i can match the pistons for a reasonable cost.

Bike TB's should help (6 No) and reducing the parastic losses like the flywheel, a/c pump , p/s pump and lighter crank pulley will aid pickup.

Omex/emerald management will provide tuning and map flexibility with a MAP sensor.

[Spireite]

Give Swindon racing engines a ring, they help develop the 2.5 v6 in the vectra gsi over the vectra Sri, they built all the 2.5 v6's for the vectra challenge series back in the day.

Very knowledgable people, Ive spoken to them when tuning my vectra 3.0 gsi

Cheers Dean

[2woody]

The Omega radiator is gigantic for the car in normal circumstances, so I wouldn't be changing that.

The block has a weird coolant flow route, including a "dual-pass" thermostat, so removal is going to be a bit more difficult than you might think.

Hang on - let's just go and have a look at a bare block I've got....

[2woody]

.....right-0 have been & seen

you'll need to make up a coolant inlet which goes into the aperture left by removing the coolant pump. This'll make things easier for you as these engines have the cool inlet to the block at the rear of the block, with the ingested coolant going through the oil cooler and into the back of the water pump.

Have seen many electric water pumps fail, most due to installation issues. the "standard" pump is much more fail-safe.

my solution would be to remove the oil cooler and pass the coolant to the water pump through a separate pipe inserted into the block.