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Discussion Starter #1
It is well known that these engines ,while lighter
do not provide the tuning potential of the b234 engine

what is to stop simply substituting the 234 block for the 235 ?

then you could get 500 hp out of it ..heh heh

I feel another project coming on ....
anyone got a 9-5 with a blown engine ?
 

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Isn't it the case that it is the pistons and con-rods that are lighter, not the block? And that it is these lighter, lower-friction components that make the B235 more efficient? And a better-flowing head, of course.

So, take a B235 engine for tuning. The pistons and con-rods won't stand much more than about 300hp so replace them with the much meatier B234 con-rods and pistons for strength, then add a gas-flowed head 'cos you want lots of horsepower.

Then you'll have the basis of a really powerful B234 with "B235" written on the block
 

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I think there's more to it that that. Bill's right in that the pistons, rods etc need to be replaced, but that's what constitutes the Maptun Stage 5 IIRC, and yet there still seems to be a 350hp limit with a B235R, so I'm guessing the limitation is then with the way T7 can be tweeked, with the differences in the way it works to the more tunable T5......
 

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There could be an ECU map limitation on T7, but I doubt it. Maybe we can get someone from Hirsch to comment on it.

Are T7's con rods really that weak? Usually horsepower isn't so much a problem with rods as RPM because most metals can withstand large amounts of compression, but have limited tensile (pulling) strength.

Personally I think a T7 engine with new pistons (and maybe rods) but with T5 ECU would be a lot of fun. The better flowing head and smoother rod-ratio would make for a good high-revving engine. The better rod ratio would also reduce vibration should you ditch the ballance shafts.


And if you really wanted to go nuts with it www.paeco.com makes custom Titanium connecting rods for about $2,000 a set of four. (Or forged Moly rods for much less) You could have rods stronger than T5 bits but lighter than T7 ones. Combine that with a ballanced internal assembly, cams, ported T7 head and an 8K redline and ... well ... you do the math.


Adrian~
 

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I've done a few conversions/transplants: put a '94 Aero drivetrain into a '92 CC, a '98 B234R drivetrain into a '92 CC, and the same '98 B234R drivetrain into a '94 white Aero. The most difficult part of these transplants was integrating the outputs from the T5 into the cabin/instruments. In the latter case, it was the most difficult because the EDU had to be changed to integrate the 2-speed cooling fan control. I couldn't imagine trying to integrate a T5 controlled engine into the cabin of a T7 vehicle. However, I do have a question: if the blocks can be interchanged, then other than where the transaxle is mounted to the sub-frame, the drive cups and final gearing, shouldn't the transaxles be interchangeable, too?
 

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Discussion Starter #10
my suggestion was not to change the whole engine but just the block
in that way retain the t7 head and control

all you change is the weak part ....
 

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Yeah, the physical block is essentially the same, save for the ballance shafts, which were converted to aluminum. (At least, that's what the WIS says. Haven't seen a B234R ballance shaft personally.)

But a B234R bottom end, with everything else B235R (head, intake, exhaust) might work really well!


Adrian~
 

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Originally posted by Adrian W:
[qb]Haven't seen a B234R ballance shaft personally.[/qb][/b]
I've had a balance shaft out of one of my B204s (same part as used in the '94-on B234) and it's steel and very heavy.

I wonder how an aluminium one would be as effective without having a much larger outside diameter?

[Edit] Just checked the EPC and it's the same part for the B205/B235 so those are steel as well.
 

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You sure? I get 91 85 588 for the 2002 B235R and a series of different part numbers, including that one, for the B234. The EPC often lists compatible parts, even if they were not originally fitted.

Here's the part I was talking about in the WIS:



Adrian~
 

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Yes, the B234 parts have been superceded by 91 85 588, which is listed for the '94-on B234/B204 now.
While I can understand that they can be lighter because they are counterbalancing a lower reciprocating mass in the B205/B235, I can't imagine they changed them to aluminium. I think that would be taking lightness to an extreme in a part that relies on mass for its function.

I see the marketing chaps have had a hand in that list - "The oil pump's overcapacity has been reduced slightly" sounds much more positive than "The oil pump's capacity has been reduced".

None of the other changes on the list has been described as "slight".
 

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While people say the tuning potential for the B235R is limited, MapTun were saying that the Stage 7 for the 9000 also has a relevant option for the 9-5 Aero, though you have to email them about it. I wouldn't mind seeing a 500hp 9-5 Aero, with the Sensonic gearbox...
 

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Originally posted by Grentarc:
[qb]I wouldn't mind seeing a 500hp 9-5 Aero, with the Sensonic gearbox...    
 [/qb][/b]
Not a lot of point in that, as it would still have to be torque limited to around 400-420Nm otherwise the sentronic 'box would soon be a pile of bits
 

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Originally posted by aeropilot:
[qb] QUOTE
Originally posted by Grentarc:
[qb] I wouldn't mind seeing a 500hp 9-5 Aero, with the Sensonic gearbox...      :fawlty:   [/qb][/b]
Not a lot of point in that, as it would still have to be torque limited to around 400-420Nm otherwise the sentronic 'box would soon be a pile of bits
[/qb][/b][/quote]*cough*
 

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As far as I know the sentronic autobox is actullay a manually box being computer controlled so I wonder if it cant be upgraded furterh?
 

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Originally posted by Søren Hviid:
[qb]As far as I know the sentronic autobox is actullay a manually box being computer controlled so I wonder if it cant be upgraded furterh? [/qb][/b]
Sentronic is a pure auto box, with 'paddles' to control the gears instead of using the transmission lever to hold a gear.
Sensonic as fitted to the gm900 was a manual box with computer controlled clutch.
 
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