98 S70 camshafts question

Shappy · Post by **Shappy** » 09 May 2024, 07:49

Can anyone on here confirm that the camshafts from a naturally aspirated motor in a 1998 S70 can be used to get a bit more power from a turbo motor? Also same question for an n.a. intake manifold. I have both removed from a clean motor.

Post by **Sveedy** » 09 May 2024, 15:51

Yes they will work fine. I believe the '93 and/or '94 NA cams had a little bit more duration, but all of them help the turbo models performance. You might want to change the camshaft settings; retard a couple of degrees on intake, and advance a couple on exhaust. Hopefully someone else here or maybe over on Swedespeed could confirm that. TDC is always safe.
The intake is only switched out to the NA type if you are swapping the throttle body's ( w/ 960 throttle plate ) as well. You also need to drill/tap for a additional vacuum port on the NA intake.

Post by **Clemens** » 10 May 2024, 15:57

Someone on Swedespeed (quite sure it was Swedespeed) did a dyno test and came to the conclusion that the NA cam swap isn't worth the effort because it moves the powerband in the rev range, but the real world gains are negligable. It might feel different after the swap, but the dyno saw no real gain as far as I remember. A good tune, a downpipe or choosing a larger turbo will make a bigger difference. if you want it all, it might be a nice addon, but this shouldn't be high on you shopping list if you're looking for more punch.

Post by **Sveedy** » 11 May 2024, 08:31

Yeah, I agree it wouldn't be my first performance mod. I did it along with the throttle body, turbo, exhaust etc and tuning on a fresh engine, so hard to say which modification made the most improvement.

Post by **abscate** » 11 May 2024, 10:32

You’ll get a lot more power with the #2 intake lifters installed, too.

Shappy · Post by **Shappy** » 11 May 2024, 11:36

I have no plans to install these parts. So if anyone on here wants them for their next build make me an offer. Lifters will be included of course.

Post by **Chuck W** » 12 May 2024, 07:07

I wouldn't take things apart to install them, but if you need to do valve seals (which most of these cars probably need at this point), that is a good time to do it.

I installed 850 NA cams in my T5 when I was doing valve seals. I set them at +2* EX/-2* IN and did notice a difference (albeit a small one) after the swap. With no other tune changes at that time.

Again, not something I would do as a stand alone upgrade, but if you're in there and the cams are already out, then yeah.

xanthefin · Post by **xanthefin** » 12 May 2024, 07:39

Clemens wrote: ↑10 May 2024, 15:57 Someone on Swedespeed (quite sure it was Swedespeed) did a dyno test and came to the conclusion that the NA cam swap isn't worth the effort because it moves the powerband in the rev range, but the real world gains are negligable. It might feel different after the swap, but the dyno saw no real gain as far as I remember. A good tune, a downpipe or choosing a larger turbo will make a bigger difference. if you want it all, it might be a nice addon, but this shouldn't be high on you shopping list if you're looking for more punch.

I did replace 1.6l engine camshafts from 1.8l and i regretted it. It moved the power to wrong spot. So yes i agree this information due experience with these

For testing i would personally only adjust cams on these engines.

dikidera · Post by **dikidera** » 12 May 2024, 08:15

Interesting this thread has occurred without me noticing it. Usually what happens with NA cams is that they have overlap to take advantage of exhaust scavenging. With VVT the overlap is increased on a NA motor to move the powerband down, but this increases overlap.

Turbo motors do not have overlap or very very little and potentially have higher duration for the exhaust to help it evacuate faster, most NA cams have 24 degree of overlap between intake and exhaust and go higher especially with VVT. Of course NOBODY, I repeat, nobody has precise information on say the RN engines. The 94 glt have some semblance of information about them on the Volvo whitepaper https://www.jstor.org/stable/44554507

Such as 8.45mm lift and 240 degrees at 0.1mm duration(this is a non standard measurement, usually done in inches such as 0.05 inches of lift or in worst case, 1mm lift). 112 degree centreline for intake(which I only assume from the paper)

It is claimed in engine theory that with high overlap on a turbo, there is reversion, somehow affected by the pressure ratio of the compressor. So exhaust is blasted back into the intake manifold, despite the intake manifold being under higher than atmospheric pressure.
The other thing is that as the intake and exhaust valves are open, the compressor is pushing some of the mixture out the exhaust. It could possibly be compensated for in Start Of Injection maps?

BUT

A lot of people have done it and claimed no ill effects with no tuning required. But horsepower is not everything, torque is most important in my personal opinion. And with NA cams you are changing the torque curve.

Just today I had a VW Touran 1.9 tdi or 2.0tdi which is 140hp blow me out of the water. The 2.0 has 330nm of torque. My s60 170hp has 220.