3.2 to 3.4 Conversion Kit for '87 911
05-19-2003, 08:15 PM
#1
1st Gear
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3.2 to 3.4 Conversion Kit for '87 911
New to Rennlist; I have an '87 Carrera that is just about ready for some valve guide work; I am considering the 3.2 to 3.4 'kit' that my local wrench has suggested. Has anyone any experience with this 'kit'? What are the upsides/downsides for this upgrade?
05-19-2003, 11:07 PM
#2
RL Technical Advisor
RT:
Nice upgrade and highly recommended.
Aside from the costs, there are no downsides. Just make sure that your compression ratio is less than 9.7:1 due to the 91 octane CA premium fuels.
Nice upgrade and highly recommended.
Aside from the costs, there are no downsides. Just make sure that your compression ratio is less than 9.7:1 due to the 91 octane CA premium fuels.
05-20-2003, 05:27 AM
#3
I think the standard Mahle 98mm Motronic conversion kit is 9.8:1. I think that compression ratio is pretty much the standard for the Mahle Motronic 3.4 conversion kits with pistons and cylinders. I like Mahle. Anyway, I think that is the same compression ratio that came in the euro cars. What I am sure of though, is that 9.8:1 is the standard compression ratio on the 80-83 european 911SC with the 930/10 engine code. I have a couple of friends that run those at the track with me, and they haven't had problems yet. They, like myself with 9.5:1, run the mixture on the rich side. With Motronic, you should not have any problems. Of course, to be on the safe side at the track on a hot day, run a little race fuel mixed in or some sort of octane booster. And maybe also disconnect the oxygen sensor. For the street, you should have no problems. The advantage to building a 3.4 from a 3.2, when compared to an SC, is the fact that you already have a 74.4 crankshaft. So all you need are the pistons and cylinders. I like this conversion a lot. It is bolt on, looks stock, no rigging involved and you will still have matching numbers on the car.
05-20-2003, 04:49 PM
#4
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Just curious, what is your expected P/E (power/expense) ratio?
I (dimly) recall Bruce Anderson in Excellence saying this wasn't a cost effective upgrade. I think he said that the extra .2 liters was less than 6% displacement increase and would therefore only increase power by approx 6% (13hp). The cost (according to BA) was pretty major. Are you replacing the P/C anyway?
No replacement for displacement, though.
I (dimly) recall Bruce Anderson in Excellence saying this wasn't a cost effective upgrade. I think he said that the extra .2 liters was less than 6% displacement increase and would therefore only increase power by approx 6% (13hp). The cost (according to BA) was pretty major. Are you replacing the P/C anyway?
No replacement for displacement, though.
