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I was just wondering what options does one have to increase their HP from around 270 Hp at the crank to 400 Hp at the crank? My current engine is a stock 164LS 24V with 44mm intake and GTA cams. Modified stock injectors and basic modifications to the engine to fit into a GTV6.

Supercharge babyyyy

Try to adapt Greg Gordon's S/C kit to the 24V. Maybe not 400 bhp, but > 320 bhp shouldn't be a big deal with reliability.

I think Greg will tell you to se another supercharger.. M(P)90 would be my bet.

400 Supercharged horses would be nice.... imagine the sound they would make.

All depends on your budget...yeah supercharging would be nice, the 24v would love it..

But of course if it was me, i'd mount two snails in there for sublime performance. You would easily reach 400-500 hp. Bigger injectors and a good ecu for full sequential injection. Noice

Properly matched turbos would have that engine screaming, or you could go for a single set-up, bit bigger turbo and have it run 12-16psi and you will not be able to wipe the smile from your face..but damn whatever you decide to do, really looking forward to see you get the ponies out of it!!

400hp out of a force fed 24 valve would be a doddle.

Something a bit different, a Rotrex (centrifugal) supercharger. It wouldn't provide the low/mid RPM torque gains the the posative displacement supercharger or even the mid-range of the turbos, but it would give the most progressive torque curve of the lot. That should help keep the transaxle in 1 piece

If you went turbo's, even a pair of R34 Skyline GTR/Garretts would supply that amount with plenty in reserve.
It would come down to engine strength and detonation control. That, and getting all the plumbing into the engine bay .
As Garth has pointed out, quallity engine management (and crankshaft position sencing) is the key to make it run smoothly with big injectors. An over powered ignition system (CDI) is also a good idea so you are't missing out on power from a challenged set of coils.

Hey cchan, this pic i took of a supercharged gtv6 with the 12v engine here in melb not long ago at a race meet, sounded very nice indeed and had alot of grunt..Over 300kw to be exact...


Location of charger gives a beautiful rear exit flow for exhaust before any bends, plenty of room for a 3".
The pipes you see at the front could be better designed for even better flow, but hey this car still flew, but yeah i would have done a slightly different design...

Which reminds me, i'm changing my intake pipe from 60mm to 80mm which will match the outlets of throttle body to intercooler, extra 20mm of flow should be lovely!!
And will re-direct slightly so that damn monster 3.0 catch can will fit!!

This looks like a cleaner design the USA kit.

Does anyone know the owner / mechanic ?

Garth was it running a rotrex?

Thanks
John

With good porting 400 hp is possible.
From 3.0 it needs very high revs. 3.5 only high.
$/HP turbo or compressor beats the NA route. In my case I can't get it road legal with either and the sleeves were worn. My goal isn't 400 either but 350 should be possible.

What you need for 400 hp:
Good ported heads
Improved intake
Good headers
A good engine management
3.5 engine over 7500 rpm 3 liters close to 9k
No space for any bad links for this power.

Sorry GP i'm not sure what it was running, he was in the pits about to hit the track..

Thanks for all the information. It looks like I have the following options:

1). Get another Motor from Glenwood Motors with 425hp directly from S.A.
2). Supercharge the 24V to 400HP.
3). Turbo the 24V to 400HP.

I was just wondering if anyone on the Forum has a 400hp or higher GTV6? And finally if you do are your running the stock transaxle or did you convert to the front mounted transmission.

Appreciate the additional information. I think my GTV6 is as tweaked as I can do it for now. Everything is upgraded/modified for the extra HP( Suspension, Brakes, wheels & tire, etc). Therefore, I was hoping to get alittle more HP if possible.

If you want more HP but not go nuts, I would recommend:

1-Shaving the heads a wee bit to get the compression up to 11:1
2-Change the cams to something else (newman, or catcams)

Those 2 mods should see gain you 20 wheel hp. That should be plenty. The GTV6 isn't that heavy, and at that power levels, a 348 GTB is probably not going to get away from your car.

If I were you and money was not an issue I would leave your 24v GTV6 alone and find another GTV6 to build. I would do a 3.5 24v twin-turbo with front mounted Getrag 6 spd gearbox. This would take serious engineering and modification, so you would need to find someone willing to build for you. Don't expect a bolt-on. I'm considering doing something like that some day...
Jes

If you go the turbo route there's no real need for 3.5 liters. Maybe some more grunt at really low rpms.

My friends 2.0 V6 (164) has 400 hp already and a 3.0 is enough to break the 116 drivetrain.

With my cylinder heads I need about 1.3-1.4 bar boost for 1 kHP.

I can get an engine delivered from here with any power from 400-1000 hp. I'm not the builder but can do the translation. It is NOT cheap though.

Yeah i agree with Micke, no need for 3.5 if its going to be boosted...3.5 would be great if it was N/A..

2.5-3.0 is plenty for boost.
Also buying another gtv6 is one way of saying its never going to be reliable...if everything is done right by the right people, the car will be very reliable, i couldnt believe what i was getting away with, running standard driveline etc, blowing away 60-70K Evo's and high price euros, honestly i couldnt stop laughing...remember less is more, nice engine , keep cams standard, with forged light weight racing pistons, complete engine management, bigger injectors, latest turbo(Garrett) and you will be creaming opposition. Out of all the cars i've been in, boosting an Alfa engine is the icing on the cake...not just because i'm an Alfa lover...hmmm twin turbo 355 would be lovely...arrrgh getting sidetracked..



I know everyone thinks that once a certain HP is reached, the rear transaxel will blow, well actually it will, but how has corvette managed to hold nearly 600hp with the gearbox in the back..? I know its had a hell of alot more engineering than our gtv6's, but i'd rather spend the cash modifying my transaxel than having a gearbox up the front..
Would love to know what can/could be done to hold more hp for the transaxel...maybe a borg warner could fit in the back...?