Who knows anything about camshafts?
Discussion
Hey there folks,
Im currently building a car to race during the 2008 season. Im using a 4.5ltr twin turbo, alloy block v8 engine. The engine is originally a VH45 out of an 1993 Infinity Q45.
As standard the cams are:
Dur @050º: - 177/176º
Adv Dur º: - 240/240º
Cam lift: - 217/209”
Valve lift: - 368/355”
But that's for the standard N/A engine.
Now my current car is running an SR20DET engine and using a 256 degree intake and exhaust cam which works well and the VH45 is (in a way) two SR20det's bolted together to form a V8 engine (that's amazingly strong by the way)
Any idea what cam spec/duration would be best suited for a twin turbo charged applicaiton?
Im currently building a car to race during the 2008 season. Im using a 4.5ltr twin turbo, alloy block v8 engine. The engine is originally a VH45 out of an 1993 Infinity Q45.
As standard the cams are:
Dur @050º: - 177/176º
Adv Dur º: - 240/240º
Cam lift: - 217/209”
Valve lift: - 368/355”
But that's for the standard N/A engine.
Now my current car is running an SR20DET engine and using a 256 degree intake and exhaust cam which works well and the VH45 is (in a way) two SR20det's bolted together to form a V8 engine (that's amazingly strong by the way)
Any idea what cam spec/duration would be best suited for a twin turbo charged applicaiton?
Edited by Bizzle on Friday 10th August 17:15
No, but just on general principles you could probably get away with something broadly similar to an NA cam. The turbo will be more-or-less pressure balanced between inlet and exhaust so I wouldn't expect any huge impact on the overlap requirements compared to NA. Having said that if it was me I'd direct the question to the experts like stevieturbo and BoostedLS1 because these are the people who've actually done it rather than just read the book.
Bizzle said:
Any idea what cam spec/duration would be best suited for a twin turbo charged applicaiton?
Do you have any string ?? it might be worth measuring its length....Edited by Bizzle on Friday 10th August 17:15
There is no real answer to this question. Head flow, manifold design, turbocharger, and usage are all factors to consider, before any real "best" can even be guessed. And then we can be horrible and throw cam timing into it with a quad cam engine !!!
As for the engine...are you saying it is actually 2 x SR20DET's ? and that cams from those engines might work fit yours ?
I know that these have a variable inlet cam, so would that affect your engine ? Thats not to say there arent some SR20DET with faulty variable cam mechs welded up
and working just fine.If those cams would fit, then fire away. 256 deg duration is still pretty tame, but would be better than the very mild 240's you have. But I wouldnt consider going much over say 264 ( common number with cams ) degrees. Idle will start to deteriorate, if that matters ?
Although you may have the ability to play with the LSA on a quad cam motor ( will you get ££££££ verniers ? ) which could tame things...
But the biggest problem with crap like that, is its going to cost time and money dyno-ing to optimise.
Another reason to keep it simple.
The only thing I can say, is that when turbocharging, mild cams work incredibly well. You still drive well at low rpm's, and they will make a lot of power up top. Even more so with small turbos and poor ( ie cast or log design ) exhaust manifolds. ( ie, no overlap to allow high EGBP to hurt anything )
And given the potential cost of having 4 cams ground.....really, Id be looking elsewhere for power, before heading down that road.
What are you using it for ? what sort of power are you after ? unless you are really intent on pushing big numbers, I wouldnt get too worked up about cam choice.
Get a good set of manifolds, good intercooling, and choose the right turbo(s) and if that doesnt satisfy you, then you could go for some headwork, and then cams.
Edited by stevieturbo on Friday 10th August 19:21
Well,
The engine is going in a Nissan 200sx S15 which im building to compete in some of the UK and European drift series next year, along with hopefully doing a few interesting things like braking the 200mph barrier. I have a fair amount of experience with "bolt on tuning" (turbo's manifolds, pistons, stroker kits etc) but in all fairness, i have always been able to buy for an engine that has been very well researched, that i know very well and has well documented --> Do this to get X features.
The problem with the VH45DE infinity engine is that it's not an engine that the tuning scene knows a lot about and nobody has done a lot of tuning with them. The Aussies and Americans have a fair bit of information but nobody apart from Nizpro in Aus, have ever built one for big hp. Everything is having to be custom made from scratch. However the engine, as a unit is very strong and people have been getting 500hp + of standard NA blocks with head work and throttle bodies.
The engine spec (so far) is:
94mm overbored forged pistons
Cylinder liners
Standard rods (honestly, they are like house bricks and forged as standard)
Knife edged lightened and balanced crank
Full bottom end balance
Custom lightened flywheel
Triple Plate cabon clutch kit
Feriday head gaskets
Valve springs (sourced from Australia)
Camshafts (sourced from the same company)
GT2835R .62ar turbos
Greddy Type 2 external wastegates
8.5:1 compression ratio
Custom twin alloy inlet plenum
90mm alloy throttle bodies
Alloy Fuel Rails
Injectors and fuel system calculations still need to be done but needless to say it will run a baffled alloy fuel tank, swirl pot etc etc.
Whole system running of a VEMS Gen 3 stand along fuel management system.
Idle really isn't a big problem as it's a track only car, never to be used on the road. Im looking to try and run around 700ft lb's of torque with the engine and keep it as responsive as possible low down in the rev range.
Sorry for waffling on, but sharing any of your knowledge would be appreciated.
The engine is going in a Nissan 200sx S15 which im building to compete in some of the UK and European drift series next year, along with hopefully doing a few interesting things like braking the 200mph barrier. I have a fair amount of experience with "bolt on tuning" (turbo's manifolds, pistons, stroker kits etc) but in all fairness, i have always been able to buy for an engine that has been very well researched, that i know very well and has well documented --> Do this to get X features.
The problem with the VH45DE infinity engine is that it's not an engine that the tuning scene knows a lot about and nobody has done a lot of tuning with them. The Aussies and Americans have a fair bit of information but nobody apart from Nizpro in Aus, have ever built one for big hp. Everything is having to be custom made from scratch. However the engine, as a unit is very strong and people have been getting 500hp + of standard NA blocks with head work and throttle bodies.
The engine spec (so far) is:
94mm overbored forged pistons
Cylinder liners
Standard rods (honestly, they are like house bricks and forged as standard)
Knife edged lightened and balanced crank
Full bottom end balance
Custom lightened flywheel
Triple Plate cabon clutch kit
Feriday head gaskets
Valve springs (sourced from Australia)
Camshafts (sourced from the same company)
GT2835R .62ar turbos
Greddy Type 2 external wastegates
8.5:1 compression ratio
Custom twin alloy inlet plenum
90mm alloy throttle bodies
Alloy Fuel Rails
Injectors and fuel system calculations still need to be done but needless to say it will run a baffled alloy fuel tank, swirl pot etc etc.
Whole system running of a VEMS Gen 3 stand along fuel management system.
Idle really isn't a big problem as it's a track only car, never to be used on the road. Im looking to try and run around 700ft lb's of torque with the engine and keep it as responsive as possible low down in the rev range.
Sorry for waffling on, but sharing any of your knowledge would be appreciated.
Can't offer any info re; cams, but you could try having a word with John Dixon (if you don't know him already) over on http://www.zclub.net and probably the 300ZX forums, he's putting a tweaked N/A VH in to a Z32. Cool pics in his gallery - http://www.zclub.net/gallery/showgallery.php?ppuse...
Cheers,
Rob
Cheers,
Rob
B19GRR said:
Can't offer any info re; cams, but you could try having a word with John Dixon (if you don't know him already) over on http://www.zclub.net and probably the 300ZX forums, he's putting a tweaked N/A VH in to a Z32. Cool pics in his gallery - http://www.zclub.net/gallery/showgallery.php?ppuse...
Cheers,
Rob
Thanks mate,Cheers,
Rob
Spoken to John quite a bit already. Really helpful bloke and seems to be known as a bit of a VH legend throughout the world!
If it was me, I'd have just thrown an LSx in there....job done. Make as much power as you want, without too much difficulty, and plenty of support.
But anyway..
With the ability to dial all 4 cams in, you will be able to venture slightly bigger with the cams, because at least you can experiment with cam timing, and LSA.
The turbo's used arent particularly big, and should spool well....so I wouldnt go mad with lots of overlap if you do go for longer duration cams. Keep the overlap down by using a wide LSA..
I think 700lbft for them might be a tad optimistic though ??
90mm Throttle Bodies ??? I think that is going to be a nightmare for throttle control. Far far far too big.
Certainly on LS1's ( airflow is airflow ) the std 75mm TB has been proven in some cases to over 1000rwhp, with very little restriction. Although most people do opt for larger.
It clearly isnt a requirement though.
2 x 90mm TB's is just madness IMO. It will perhaps give you a useful throttle window of say 0%-30%, and which point the engine will have access to all the air it needs anyway, so that 30-100% is wasted.
You want to use a 90mm TB....just exactly how big is your intercooler plumbing ?
I laughed and replied once to a well known Cossie tuner, who seemed to think if the cars owner wanted to fit a larger TB to the car, he would also have to upgrade his intercooler too.
When I pointed out the fact that the TB Blade would still in fact be smaller than the IC pipework currently on the car, they didnt have a response.
So is your IC pipework 90+mm ?? Is there any sensible reason for suggesting anyone could ever need such a large TB, nevermind 2 of them ?
Is the outlet on your turbochargers big...or is it simply 2" ?
But anyway..
With the ability to dial all 4 cams in, you will be able to venture slightly bigger with the cams, because at least you can experiment with cam timing, and LSA.
The turbo's used arent particularly big, and should spool well....so I wouldnt go mad with lots of overlap if you do go for longer duration cams. Keep the overlap down by using a wide LSA..
I think 700lbft for them might be a tad optimistic though ??
90mm Throttle Bodies ??? I think that is going to be a nightmare for throttle control. Far far far too big.
Certainly on LS1's ( airflow is airflow ) the std 75mm TB has been proven in some cases to over 1000rwhp, with very little restriction. Although most people do opt for larger.
It clearly isnt a requirement though.
2 x 90mm TB's is just madness IMO. It will perhaps give you a useful throttle window of say 0%-30%, and which point the engine will have access to all the air it needs anyway, so that 30-100% is wasted.
You want to use a 90mm TB....just exactly how big is your intercooler plumbing ?
I laughed and replied once to a well known Cossie tuner, who seemed to think if the cars owner wanted to fit a larger TB to the car, he would also have to upgrade his intercooler too.
When I pointed out the fact that the TB Blade would still in fact be smaller than the IC pipework currently on the car, they didnt have a response.
So is your IC pipework 90+mm ?? Is there any sensible reason for suggesting anyone could ever need such a large TB, nevermind 2 of them ?
Is the outlet on your turbochargers big...or is it simply 2" ?
Bizzle said:
Hey there folks,
Im currently building a car to race during the 2008 season. Im using a 4.5ltr twin turbo, alloy block v8 engine. The engine is originally a VH45 out of an 1993 Infinity Q45.
As standard the cams are:
Dur @050º: - 177/176º
Adv Dur º: - 240/240º
Cam lift: - 217/209”
Valve lift: - 368/355”
But that's for the standard N/A engine.
Now my current car is running an SR20DET engine and using a 256 degree intake and exhaust cam which works well and the VH45 is (in a way) two SR20det's bolted together to form a V8 engine (that's amazingly strong by the way)
Any idea what cam spec/duration would be best suited for a twin turbo charged applicaiton?
its the most complex part of an engine.Im currently building a car to race during the 2008 season. Im using a 4.5ltr twin turbo, alloy block v8 engine. The engine is originally a VH45 out of an 1993 Infinity Q45.
As standard the cams are:
Dur @050º: - 177/176º
Adv Dur º: - 240/240º
Cam lift: - 217/209”
Valve lift: - 368/355”
But that's for the standard N/A engine.
Now my current car is running an SR20DET engine and using a 256 degree intake and exhaust cam which works well and the VH45 is (in a way) two SR20det's bolted together to form a V8 engine (that's amazingly strong by the way)
Any idea what cam spec/duration would be best suited for a twin turbo charged applicaiton?
Edited by Bizzle on Friday 10th August 17:15
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