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Blueprinting- the options

6K views 34 replies 16 participants last post by  California Saab Tuner 
#1 ·
I'm considering blueprinting my '93 B234. A pressure test has shown that the compression diference of 25psi is down to a leaky piston ring/worn bore on cylinder #2. So, it's a lump out job to rectify that. Given it's out, I'm contemplating having it blueprinted for maximum balance and smooth perfromance.

On the "definite" list is:
<ul type="square">
[*]Lightening/shot peening the rods
[/list]
<ul type="square">
[*]removing the balancer shafts and chains
[/list]
What other options would folk consider, and what are the benefits?

Cheers

Mark
 
#3 ·
Removing the balancer shafts will make the engine less smooth, more raw but it should rev more readily, according to experiences documented by Kevin Yankton anyway. Certainly, my car is much smoother with nice new chains. But that said, I'm not planning to attempt to get > 300bhp out of the lump in mine, so I've gone for safety and stability over sheer performance.

Lightening the rods sounds like a good idea, nice to do if you can afford it.
 
#6 ·
* Lighten the flywheel

* Shot peen crankshaft

* Of course, balance complete rotating assembly.

When digging this deep into your engine, you might consider going all the way and install billet rods (the originals are pleny strong, but also quite heavy), crankshaft and forged pistons...

BTW - oil cooling jets for the piston decks were only incorporated in B235R and 205 hp spec B205R engines, right? In that case...
 
#8 ·
Are you into real blueprinting to get the max power while still having the car "in spec"? Or are you going beyond that to get max power at any (reasonable) risk?

You can grind the big ends to max off-centre to increase the stroke. This will mean going to the minimum journal diameter, so no more re-grinds possible. Obviously this is self limiting as you weaken the journal as you increase the stroke.

Take the bores out to max. Again a balance of extra cc's against risk of cracked block.

Lighten the pistons. More risk.

Remove a piston ring or two to reduce friction. Probably not for you unless you rebuild engine between trackdays.

There are some production engines where the block was stiffened by welding / bolting cross-bracing to the outside of the block.

X-Ray every thing for cracks - especially the con rods. Cheapest way to do this (I'm told ) is to date a hospital radiographer


Good luck!!
 
#9 ·
you don't need to lighten the rods, just get them checked for cracks and then polish and shot peen.
You will benefit from knife edging the crank and then getting it polished. You then take it out to max bore and fit cosworth forged pistons, these are considerably lighter than stock and much stronger. This is where you will make best gains and it gives the con rods an easier life also...less weight to keep hold of at max revs!
The flywheel can be lightened extensively also.
Get the head gas flowed by a company who do it as a living...they have the expertise. Then get the whole lot balanced together.
 
#10 ·
I'm not aiming to go too OTT on this.. I just figured that whilst I had the lump out (or alternatively find a decent s/h one to work on) I may as well get a few reasonable mods done that would give me a performance benefit.

It's useful to know all the options and consider the performance vs cost benefit.

I know that taking the balance shafts out will make things rougher but by having it balanced, I hoped to counteract some of that.

Ref cams, I understand the trick is to get hold of a very early set of 9000 cams, which were ground much more aggressively. My local indy reckons that it was found that too many folk were planting their 9000s in hedges etc not being used to such power and acceleration in a family saloon when they first came out so Saab turned the wick down a bit.

I'm certainly considering mild overboring, not so much to increase capacity but to lower the compression ratio which will be better suited to higher boost levels.

Once I've got my potential shopping list together, I'll make enquiries of various specialists.

I already have the head ported & flowed with big exhaust valves.

Don't forget that in doing this I'm going to have to consider the gearbox budget as well
...
 
#14 ·
If it's a B234R it already has good (albeit not too terribly lightweight) forged pistons. They're easily useable past 25 psi of boost as Mr Yankton has shown. Shotpeening the rods is always good, as is checking for crack's in it, the crankshaft, and the head if it's coming off as well. A lot of people have been putting anti-friction coatings on the pistons skirts, and ceramic coatings on the piston tops, combustion chambers, and exhaust valves. You might consider looking into those. (http://www.performancecoatings.com/) I hear fully coated engines run much much cooler and with lower emmissions. (The ceramic coatings reduce the pocket cooling of small amounts of gasses in the cyllinder. This gives it a better burn.) Some of the anti-friction coatings can go other places as well: Crankshaft journals, piston pins, cyllinder walls, camshaft lobes, lifter bores, insides of headers to smooth gas flow. Also consider Total Seal gapless rings. They aren't very good for high revving, and you won't see much advantage out of the box with them over the stock rings. But after 80K miles or so, they typically show very little leakdown comparitively. Not sure how good they are with high boost. Just worth looking into ...

ciao
 
#15 ·
Originally posted by Mark E:
[qb]I'm certainly considering mild overboring, not so much to increase capacity but to lower the compression ratio which will be better suited to higher boost levels.
[/qb][/b]
I'm really confused now. Surely increasing the bore increases the swept volume, whilst the volume with the piston at TDC stays the same. Therefore the volumetric compression ratio will increase. Or have I lost the plot completely?
 
#18 ·
But hey, a nice set of low compression Cosworth forged pistons would fix that.  [/b]
Thats what I did...expensive though!!


I was going to get the pistons coated with an anti detonation coating but whilst it was only £25 per piston I was told the cosworth pistons were more than adequate for my application of running up to 2 bar boost spike with 1.6 bar steady boost pressure assuming fueling was correct. Thinking back now maybe I should have had it done, extra protection in case of lean mixture times!

http://www.ctgltd.co.uk/technology.php?id=...Crown+Treatment
 
#20 ·
If you read in some of the other threads they talk about how the B234R pistons are STRONGER than the B235R, and the B235R I know is forged ... also I believe it was mentioned then as well that the B234R's were forged. Even from deduction though, it's clear they must be. Along with the crankshaft and rods. Hell even the old C900 16V engines had forged cranks and rods. Tough stuff ...
 
#21 ·
this was something that was on my list of things to do...
my shopping list was to knife edge and balance the crank /shot peen and polish/matchweight the con rods
and (if I can afford it)max rebore and cossy pistons
otherwise just change the piston rings (mine have done 190 k)
methinks this will be the most cost effective
on balancer shafts ...two minds
save a little hp
but a little rougher
however to do this will you not have to change the chain path/make it shorter ?
this kind of mods has me nervous as the std set up works so well...
I would like to take the red line out a bit (7k)

mark in ireland sounded quite ok with the job CTM did for him and I have heard other good reports
so they are the current front runner
 
#22 ·
I'm not a huge fan of ballance shaft removal, or disabling. Not to say that they're necessary. But my personal oppinion on the matter is that they should remain functional as long as any one of these three things is still true:

1. The car is mostly stock, and daily driven.

2. The redline is unaltered.

3. The engine isn't ballanced.

Removing them does give a performance benefit. But not a significant one. Mr Yankton since removed his from his highly tuned (but not high revving) 9000 Aero from the 268 hp 372 lb ft dyno run. He also hugely upgraded his intercooler, slightly upgraded his ECU, and slightly upgraded his turbo since then as well. Between all those mods he only gained 23 hp and 12 lb ft of torque. Now I'm not downing his car or tuning methods at all. I'm actually QUITE envious of the lucky buyer. But, it's fairly clear the ballance shaft disablement didn't make any huge performance benefit, and unless you're going to hugely upgrade the motor in the future, it just doesn't seem logical to remove them. They help your car run like the silky smooth Saab it is, and who can't appreciate that?
 
#23 ·
Don't know how relevant/practical this is but one of the problems the Saab F3 engines had in their brief career during the 80s was that the competition was running hollow camshafts & other internals were more lightened, while the Saab engine was closer to standard. The effect was that while the Saab engine produced good top-end bhp on the dyno and didn't break too often, its extra rotating mass meant more inertia so it lost out some on accelaration.

With regards the balancer shafts, don't know about modern engines, and I know V-engines are quite different to in-line, but a V4 with a duff balance shaft gear runs as lumpy as hell...
 
#24 ·
Oh, and another thing to consider...

What about matching & flowing all the inlet/exhaust ports & joints to get smoothest flow, like manifold to head etc. That's always supposed to be a good "traditional" way of tuning cars rather than ECU tweaks.

For what it's worth, my old man used to run an ex-Needell/Kentish Saab Turbo Challenge car (C900 T8) which had a very expensive (£20K+ I heard) blue-printed, but supposedly stock hardware, engine. Once we'd got rid of all the weird tweaks which made it fast but undriveable on the road (e.g. the cold start valve was frihgged about to create a 5th injector!) we had it rolling roaded at IIRC 178bhp (standard 155), so it made quite a difference.
 
#26 ·
Mark,
What fliptop was referring to was the matching of the ported/flowed head to the manifolds, rather than just the head being done.
In other words, putting on a flowed and ported head and then just bolting back on the manifold is only half the job, the inlet manifold needs to ported and flowed to match the head. Ideally the exhaust manifold as well, but not sure on the practicaltity of doing this with a 9000T...don't see why not though, even better, fit one of those 4 branch jobbies like the guys at Maptun..
 
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