taffelman

Hi

Is there any tuning potential in the early 4,5 Litre engines? (RoW: 240 Hp)

I'm asking because there are some cheap manual oldboys in the market here, and I'm thinking it would be fun to build a cheap "lightweight" track car, But 240 HP is not enough juice.

One advantage is that the RoW 80-83 non-S version came without AC, lighter 911 seats, etc.. and where the lightest 928 ever made (1450 kg).

- Is it possible to take the 4,5L up to about 300Hp without costing too much?
- Is there any big difference in the brakes on the 4,5L vs 4,7L S-version?
- Is there any other reasons not too choose a 4,5L over a 4,7L?

Ben

I guess you could tune the 4.5 up, but the easiest/cheapest thing is probably to throw a ROW 4.7 engine in there from a parted out car.
I'm not too sure, but did the early ROW S model engines come with K Jetronic? If so, that would make the engine swap real easy.

Pfunde

I did that, and it's very easy. Engine was 3.000,- euro's incl. install. But you migth go for a new single cluth + 1000 euro. And brakes.......and.....

ceedee

what is a single clutch?

Mark

single DISC...as opposed to the dual disc'ers

gruffalo

the 80 - 82 non-S cars have identical brakes to the S, except for the air ducts, but they can easily be fitted. The engine is sort of a hybrid between the early 4,5L and the S engine, having the higher CR (10:1) and double valve springs among other things. The early 4.5L's are better suited for forced induction having a CR of 8.5:1 only.

So I second what the others say, a 4,7L S engine is a direct bolt on fit. My best advice is to search for one in Sweden. This week a complete running (but with body damage) early S sold for 10k SEK.

I'm looking for a 4.7 myself, but my current engine is recently rebuilt and as new, so I'm in no hurry. Patiently waiting for the right one to show up.

Imo000

I thought the S breaks were bigger and better than the non S.

SharkSkin

Supercharge an OB -- that will increase the juice....

gruffalo

The late Euro non-S cars got the S brakes somewhere between MY 80 and MY 81. Don't know about the US cars though.

MM

Vilhuer

ROw 4.5L got S brakes in middle of '80 MY, US models goth them in beginning of '82 MY.

taffelman, are you sure '81-82 ROW 4.5L was available without AC? Non AC heater was available in '78-79 MY but I'm not sure it was still possible to get it in eighties.

Imo000

Thanks for the info. I think the S breaks in the US/Canada became standard option starting with the '83 model year. Interesting how they were availble a year or two earlier everywhere else.

drnick

just import one of the 85/86 usa shortblocks and build a hybrid engine for it.

GRTWHT

[QUOTE=taffelman]Hi

Is there any tuning potential in the early 4,5 Litre engines? (RoW: 240 Hp)

Hi there, I have one of these 4.5L 10:1 240BHP 928's (1981). Was interested in you asking about tuning these older engines for greater power. I put my car across a dyno the other day and the operator wasnt confident enough to do a full throttle run because of the fuel mixture beeing to lean (14.1:1 at best, must find out how to change that!). I guess I'm jumping on this post to ask if anyone has played around with there K Jetronic system for performance tunnig???
I'm running around 30* total ignition timing and the engine still wont ping, but needs more fuel. I'm sure the engine will put out more than 240bhp once sorted, it has a free flowing exhaust fitted (non standard).

Just would like to reopen this post for some clues to unlock some HP out of the 4.5L

Cheers,
Glenn
'81 9-2-8

glork98

CIS mixture is tuned using an Allen wrench. There's a special tool available that goes through a hole on the air box and into a screw. The screw adjusts the position of the fuel distributor piston compared to the air valve arm. Pull the airbox and it'll be clear.

This make dyno tuning easy. Do a run, tweak the A/F, repeat until happy. The same can be done with the spark advance. A couple more degrees early and it'll perk up a bit.

A dyno tuning seassion is probably the best cost/benefit thing you can do. After it you'll know if there's a problem with the enge as well.

Lance J

911 guys have digital wur regulators