KV6 190 - Upgrades?? - Page 4

Dragrad · 29th July 2016, 00:34

Thread moved to a more appropriate forum. Re-direct left in old. This may be the better forum as threads get ‘lost’ very quickly in the General Forum.

TomRS · 29th July 2016, 05:44

Quote:

Originally Posted by Mr bountyfull

I have sent the Prof a pm as I cannot comment on that thread. Hopefully he might see this and look towards the top left!!!!

It is a lovely car mind!

minimutly · 30th July 2016, 00:19

So the kv6 is weak? Where then? Easy statement to make, but no-one seems to have specific information.
One thing is for certain, the low, and mid range torque is diabolical. A 2.5 litre engine should do better, especially with the cams it has, but I believe the missing torque is down to cam timing. It has zero overlap, the inlet opens at tdc!
So i believe a retiming would solve the poor low end, however, this would likely lose some at the top end, but it would make for a better drive, since torque is what drives you forward. As far as the engine itself goes, the heads are well designed (this is the major factor in producing power), with the same valves as the zr160 (160 bhp from an 1800, which can be tuned to 280bhp, although without the vvc).
So, conventional tuning on a roadgoing 2.5 litre would suggest it should make 220 and still creep below emissions regs, but any more would need supercharging. Retime the cams, change the exhaust manifold, and back box, k&n panel filter and you should be there. Going to 280deg cams would really wake it up, but it would fail emmissions tests.

minimutly · 30th July 2016, 00:31

And while were at it, its easy to say a lightweight intergra is a flying machine, well my old zs with 180 bhp wasn't slow either - the zt is a heavy car, no doubt about it, and needs real torque to make it accelerate well.

Neil1 · 30th July 2016, 10:44

Quote:

Originally Posted by minimutly

And while were at it, its easy to say a lightweight intergra is a flying machine, well my old zs with 180 bhp wasn't slow either - the zt is a heavy car, no doubt about it, and needs real torque to make it accelerate well.

I agree with this, all our cars are heavy whether it's the 75 or the ZT.

I had a real problem the other day as this small diesel Seat left me standing and I don't hang around.

So it's definitely down to the weight.

minimutly · 30th July 2016, 17:53

Well the weight doesnt help, but in gear accelleration of the v6 isnt good, and the 190 no better than the others.
I was in the middle of doing a repair on our "hack" rover 25 (burnt an exhaust valve somehow, but its done 150k), when i thought about this ome more.
The 1400 200 and 25 rovers made 105 bhp, double 1400 is 2800, which for equivalent cams, valves and timing should make 210 bhp. Now the v6 has way better cams (245 degrees vs 270 odd, call it 265 if you want i dont have the specs to hand), and more to the point way bigger valves. So its down on the theoretical twin 1400 by 8 or 9%, which could account for 17/18 bhp, but that still leaves it short at the top end. And thats not the point, the top end isnt the issue, its low and mid range that it feels inadequate.
So there we are rover managed to make a pigs ear out of a sweet v6, one day this year i'll bqe testing the cam timing theory, I'll let you all know what I find.

Neil1 · 31st July 2016, 10:27

Quote:

Originally Posted by minimutly

Well the weight doesnt help, but in gear accelleration of the v6 isnt good, and the 190 no better than the others.
I was in the middle of doing a repair on our "hack" rover 25 (burnt an exhaust valve somehow, but its done 150k), when i thought about this ome more.
The 1400 200 and 25 rovers made 105 bhp, double 1400 is 2800, which for equivalent cams, valves and timing should make 210 bhp. Now the v6 has way better cams (245 degrees vs 270 odd, call it 265 if you want i dont have the specs to hand), and more to the point way bigger valves. So its down on the theoretical twin 1400 by 8 or 9%, which could account for 17/18 bhp, but that still leaves it short at the top end. And thats not the point, the top end isnt the issue, its low and mid range that it feels inadequate.
So there we are rover managed to make a pigs ear out of a sweet v6, one day this year i'll bqe testing the cam timing theory, I'll let you all know what I find.

Could the V6 be turbocharged?

charlie 22 · 31st July 2016, 17:44

I have heard it could with low boost.

Avora · 31st July 2016, 17:54

Quote:

Originally Posted by Neil1

Could the V6 be turbocharged?

Anything is possible, but with custom exhaust and inlet manifolds, exhaust down pipes, larger injectors, pipe work and stand alone engine management being required. You'd want to be fitting low compression forged pistons and pursing real power to make it worth while.

As most will say, you'd be better off starting out with a better base engine. Something already turbocharged and designed for boost. You'd also soon run out of grip with front wheel drive, where does it end.

I have often wondered about making this car and engine more powerful, but I always conclude I could buy something else which would offer more from the start for less money.

Salad-Dodger · 31st July 2016, 19:18

I've been looking into getting a bit more from the 2.5 v6 but it does look as though it'll be a tough call. Quad cam engines with slave driven cams are not a good idea!
The last of the engines had a few changes to bring them up to where they are now. Different gear raitios and a change in big end shell material (apparently), plus a change of cam profile and timing. Oh, and a slightly larger bore exhaust system.

I had a big end break up on the engine that came with my car. Ended up replacing the whole unit and I fitted a propper oil cooler and pressure guage. The problem lies with the design. With transvers engines, there's only so much space available so the shorter the engine, the more chance it will fit across the width of the engine bay . The big end bearings are only 17mm wide which isn't a lot considering the stress/temps it has to endure. If you want some more power, reliability will be short. A lot of money will need to be invested to get to where you want to go. Its not enough to just mod the unit you are running. You will need to start from the beginning with a dedicated unit out on the bench, then find an uprated oil pump. The exhaust manifold is, in a word, dire. The porting on the inlets is not that bad but a polish would not go amis. Larger valves may be possible. Don't forget too though, that the method of cam timing is not all that wonderful. A vernia system would be better but the "slave" driven exhaust cam disign would need some investment to get the timing right.
If you want to go turbo you will need, probably better pistons but when I was competing years ago, it was a given thing that the money was going to be spent whatever the spec you wanted, but there's no easy fix here. You will need some money!
What you are looking at here is a pretty good stock motor, but pushing it further will be expesive. It may be a better bet to find another car that has a better motor! Engines in modern cars are definately built to a buget and don't lend themselves to modifications. Its enough to expect them to survive a normal useful life. Steve

29th July 2016, 00:34	#31
Dragrad This is my second home *None DROWNED** Join Date: Aug 2007 Location: Cardigan Posts: 33,339 Thanks: 1,257 Thanked 1,664 Times in 1,081 Posts	Thread moved to a more appropriate forum. Re-direct left in old. This may be the better forum as threads get ‘lost’ very quickly in the General Forum. __________________ Andrew Ich Dien Problem solving is... lateral thinking SEARCH FIRST ...ASK LATER...

31st July 2016, 17:44	#38
charlie 22 Posted a thing or two MG ZT-T 2.5V6, Mazda Cx30 Join Date: May 2011 Location: Greenford Posts: 1,137 Thanks: 875 Thanked 165 Times in 132 Posts	I have heard it could with low boost. __________________ Ugly Duckling

30th July 2016, 00:19	#33
minimutly Posted a thing or two mg zt Join Date: Mar 2014 Location: cardigan Posts: 1,087 Thanks: 28 Thanked 187 Times in 158 Posts	So the kv6 is weak? Where then? Easy statement to make, but no-one seems to have specific information. One thing is for certain, the low, and mid range torque is diabolical. A 2.5 litre engine should do better, especially with the cams it has, but I believe the missing torque is down to cam timing. It has zero overlap, the inlet opens at tdc! So i believe a retiming would solve the poor low end, however, this would likely lose some at the top end, but it would make for a better drive, since torque is what drives you forward. As far as the engine itself goes, the heads are well designed (this is the major factor in producing power), with the same valves as the zr160 (160 bhp from an 1800, which can be tuned to 280bhp, although without the vvc). So, conventional tuning on a roadgoing 2.5 litre would suggest it should make 220 and still creep below emissions regs, but any more would need supercharging. Retime the cams, change the exhaust manifold, and back box, k&n panel filter and you should be there. Going to 280deg cams would really wake it up, but it would fail emmissions tests.

30th July 2016, 00:31	#34
minimutly Posted a thing or two mg zt Join Date: Mar 2014 Location: cardigan Posts: 1,087 Thanks: 28 Thanked 187 Times in 158 Posts	And while were at it, its easy to say a lightweight intergra is a flying machine, well my old zs with 180 bhp wasn't slow either - the zt is a heavy car, no doubt about it, and needs real torque to make it accelerate well.

30th July 2016, 17:53	#36
minimutly Posted a thing or two mg zt Join Date: Mar 2014 Location: cardigan Posts: 1,087 Thanks: 28 Thanked 187 Times in 158 Posts	Well the weight doesnt help, but in gear accelleration of the v6 isnt good, and the 190 no better than the others. I was in the middle of doing a repair on our "hack" rover 25 (burnt an exhaust valve somehow, but its done 150k), when i thought about this ome more. The 1400 200 and 25 rovers made 105 bhp, double 1400 is 2800, which for equivalent cams, valves and timing should make 210 bhp. Now the v6 has way better cams (245 degrees vs 270 odd, call it 265 if you want i dont have the specs to hand), and more to the point way bigger valves. So its down on the theoretical twin 1400 by 8 or 9%, which could account for 17/18 bhp, but that still leaves it short at the top end. And thats not the point, the top end isnt the issue, its low and mid range that it feels inadequate. So there we are rover managed to make a pigs ear out of a sweet v6, one day this year i'll bqe testing the cam timing theory, I'll let you all know what I find.

31st July 2016, 19:18	#40
Salad-Dodger Gets stuck in MG ZT-T 190 Join Date: Feb 2015 Location: Chatham Posts: 592 Thanks: 34 Thanked 66 Times in 62 Posts	I've been looking into getting a bit more from the 2.5 v6 but it does look as though it'll be a tough call. Quad cam engines with slave driven cams are not a good idea! The last of the engines had a few changes to bring them up to where they are now. Different gear raitios and a change in big end shell material (apparently), plus a change of cam profile and timing. Oh, and a slightly larger bore exhaust system. I had a big end break up on the engine that came with my car. Ended up replacing the whole unit and I fitted a propper oil cooler and pressure guage. The problem lies with the design. With transvers engines, there's only so much space available so the shorter the engine, the more chance it will fit across the width of the engine bay . The big end bearings are only 17mm wide which isn't a lot considering the stress/temps it has to endure. If you want some more power, reliability will be short. A lot of money will need to be invested to get to where you want to go. Its not enough to just mod the unit you are running. You will need to start from the beginning with a dedicated unit out on the bench, then find an uprated oil pump. The exhaust manifold is, in a word, dire. The porting on the inlets is not that bad but a polish would not go amis. Larger valves may be possible. Don't forget too though, that the method of cam timing is not all that wonderful. A vernia system would be better but the "slave" driven exhaust cam disign would need some investment to get the timing right. If you want to go turbo you will need, probably better pistons but when I was competing years ago, it was a given thing that the money was going to be spent whatever the spec you wanted, but there's no easy fix here. You will need some money! What you are looking at here is a pretty good stock motor, but pushing it further will be expesive. It may be a better bet to find another car that has a better motor! Engines in modern cars are definately built to a buget and don't lend themselves to modifications. Its enough to expect them to survive a normal useful life. Steve