[Eric van Spelde]

Any reason why cams from a 'long' engine (B202,234) wouldn't work in a T7 (B235) cylinder head?

TIA,
Eric

 

[California Saab Tuner]

Can't see why not ... people have put the T7 head on the long block engine. But I'm not sure, could be of a different spec ... hmm

Dubbya~

 

[genuinesaab]

I have installed a few 900 94-98 B204 ,9000 B234 94-98 cam sets in the B235R (I personally have 01 Viggen) You will loose some of the low end torque but there is more than enough added to the top. IMHO Makes it more drivable. Just seems to keep pulling! Let me know if this helps.

Some figures for your amusement.
Relevant Cam Numbers Link
my car
NCT

 

[California Saab Tuner]

It appears the Viggen cams also have 7 degrees more valve overlap. Better scavenging effect at low boost, which helps mileage and power on low boost, but less tolerance for high boost because it can cause a reversion.

At high boost there is a lot of backpressure. In some cases with too high overlap, since in order to drive the turbo you need higher exhaust pressure than intake pressure, exhaust can force its way back into the intake side.

On the other hand, most of the more modern turbo cars use high overlap because then they don't need to use as much boost to get the same power.

What I wonder, (in the interest of just general cam interchangability) is whether there would be benefit going from the B205R's cams to the B235R's cams. Or even to the B234R's ... either way it would add quite a bit of power as the B205 seems to have rather poor cams.

Anyway ... ty for the info Nick. I'm suprised the new full 3" exhaust didn't make any more power. You'd think it would have. Maybe just different conditions this time.

Dubbya~

 

[Eric van Spelde]

Well, I was more wondering about the physical interchangeability. I have a set of Crower regrinds in Saabine's B202 head, and I'd like to transfer them to the new T7 head she'll get shortly...

 

[California Saab Tuner]

I'm not sure I can help you there Eric. But I might be weary of putting aggressive cams meant for the B202 head into the B235R head. The valve angles may be different, or the lengths or any number of other variables. Could cause problems.

I am interested in whether you're getting the T7 head with the HO Nimonic Exhaust valves. Probably are.

I just found something else interesting that Nick T may appreciate. I don't know what the lift is for the B234i cams, but the timing for the cams is great for high end. The inlet and exhaust durations are far longer than the B235R's cams. And strangely, despite being naturally aspirated it has less valve overlap than the B235R, and about the same as the B234R. That means, if the lift is comparible with the turbo cars (no doubt it is, I think Saab put more aggresive cams in the Naturally aspirated models) then you could get even MORE power with the N/A cams.

The timing of the inlet cam is also a bit later, which puts the power higher up in the RPM band where the T7 head can really breathe. Might be interseting to try those out, if Nick hasn't already.

Sorry to hijack your thread Eric ... really wish I could help, but I'm not sure if anyone's tried that yet. Could always just see if they fit? I'd really reccomend getting a new set made. Unless someone knows better?

Dubbya~

edit: Another thing to consider is what has been done to the T7 head. Larger valves etc. If it's completely stock, I would reccomend leaving it mostly stock. Especially stock when it comes to port and polishing. A flowbench like Abbott has cannot necessarily reproduce the swirl effect you get on a modern computer designed head like the T7 cars have. Changing the cams could upset that as well. Porting defnitely would upset that, so I would stay away from it, or larger valves, until you absolutely need the extra flow at high revs. Really not sure about those cams being physically iterchangable, when I had the Viggen's valve cover off it looked nearly idential to my B212 head ... but it could be different.

 

[Eric van Spelde]

Adrian, all I know it's a T7 (9-5) head that's been built by Sweedspeed to be put on the 900 race car he'd been planning to rebuild. As the stripped/strenghtened/prepared shell he also built for the purpose has gone, there's little chance of that happening - so he offered it to me for 1.500 euro after hearing my problems with the top end rattle on the dyno (all timing components on my car were put in brand new, BTW). It's got bigger valves and porting work done in addition to being modified to fit the long block.

 

[California Saab Tuner]

Really wish I could help. Hopefully if he's sending camshafts with it they'll be sufficient. If not, I wish you luck in finding, or buying another pair. Make sure to let us all know how it turns out. Sounds like a hoot.

Dubbya~