vinyl_tien

I have 3 engines in hand (all need rebuild), and going to keep one engine for my S4
I want to build NA stroke engine with ITB (I need at least 400HPs), I am planning to spend 10Kon parts.
What kind parts I should keep for these 3 engines?
1.87 S4
2.90 S4
3.85 Row
Need your guy’s input
Many thanks!

atb

If you're going to bore the block you'll want to measure wall thickness. The '85 will most likely be the best candidate. They have a reputation of having thicker wall castings then the later S4's.
The heads off the '90 have thicker bosses for the headbolts, so may be the best choice for heads.
Although you don't have one, the oil pan baffle/pickup set up out of a '78/'79 is popular for its oil control characteristics. Everything else is going to get tossed in a stroker project, so the rest of the parts don't really matter.
The only other observation I can make is that when you use the words "budget" and "stroker engine" in the same sentence, you can almost consistently exchange the word "expensive" for "budget" and "grenade" for "stroker engine" and come away with the same meaning.

Rob Edwards

Block from the '85 (theoretically thicker cylinder walls), heads from the '90 (definitely thicker bosses around the head bolt holes) .

Unless the exchange rate between Taiwan and the U.S is a lot better than I think it is, you're going to spend a lot more than $10K on parts. Just the crank, rods, pistons, and bored/nikasiled block will be $10K. An ITB setup is at least a $3-4K proposition, just the pieces themselves.

Speedtoys

Rob:

Mainland China has duplicated all of this for about $85..in quantities of 10,000.

No probs..start a group buy.

danglerb

85 Row most likely is a 4.7 block, not a good choice vs 5.0 later block is it?

Normal stroker very unlikely with less than $20k.

Maybe if you keep stock pistons and just add a stroker crank, making something like a 5.5L instead of 6.4L (stroked and bored), then add better cams and some head and intake work?

Hilton

The cheapest way to do it would be, to start with the 90 S4 motor, and add:

• GTS crankshaft (i.e. bump to 5.4L)
• Custom cams from one of the custom cams providers here on Rennlist
• ITB setup and custom intake
• Sharktuner Alpha (i.e. using MAP sensor - so no need to worry about MAF during intake design)

Keep the 87 engine for spares in case you blow up the 90 engine - but the 90 has better heads, better pistons (higher compression), and possibly the GT-style rods, so I'd stick with the 90 engine as a whole.

If that all goes swimmingly and you're not happy with the result, buy some used Porsche 968 pistons and have the 87's block bored out to 103mm (giving 6.0L from memory), then transplant the heads/intake/pistons/crank off the 90 engine.

However I'd start with the route that doesn't involve boring the block (GTS are also 100mm bores, like the 5.0L engines - so the GTS crank is a "stroker crank"), as once you start boring Alusil, you're opening yourself up to a whole lot of risk relating to your workshop's experience and availability of correct tools/materials to correctly finish the newly-bored cylinders in an alusil block (its not done with a cross hatch and stones like iron blocks).

jeff spahn

So I could have put a gtd crank and some cams in my s4 when I jd the engi be apart and had a hybrid 5.5l? Has anyone done this

Cheburator

A GTS crank only would not work as you need to change the rods and the pistons too. Best budget stroker for the money involves:

1. GTS crank + GTS rods 2nd hand - several sellers here on rennlist asking around $2000

2. Bore the block to 104mm - no idea of costs of doing this outside of the UK

3. Custom 104mm pistons from JE Pistons designed to run in alusil bores - $1550

Gives you 6.0ltrs displacement... Almost as good as a 6.5ltr stroker minus the headaches of custom crank, rods and pistons

heinrich

Really? A GTS crank AND rods for $2,000? I find that very difficult to believe.

Cheburator

yes. i got offered 2 on rennlist in that ball park figure in private messages when i was wondering what to do with my race engine. must have been my warm and fuzzy personality driving prices down i guess

heinrich

Please PM me their details so I can buy from them, I am in the market.

vinyl_tien

Thanks you guys input. That really help me.
To Bore the block in Taiwan is very cheap about 200USD, but the hardest thing is balanced crank with piston, I can not find factory who has experience.(Is that really hard?)
I think I might stay same block with stroke crank, make it to 6L
Another question, Is ITB can gain any HP?

928er

1. Put 20K in an account for your budget stroker build
2. Add more money when you run out.

This is especially true if you are building your 1st stroker engine.

Don't even try the itb route yet.

Tom. M

Just remember...boring a 928 block is not the same as boring a steel block... Alusil requires a special process and uses the Sunnen honing machine... search renny for details on the proper boring procedure..

terry gt

buget stroker .....