 2.7 CIS to Carbs - how much HP loss? |
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Friday, 18 July 2025 |
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| Scott S |
 Jul 2 2009, 03:15 PM
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Small Member  Group: Members Posts: 1,698 Joined: 30-April 03 From: Colorado Member No.: 633  |
Hi All -
Got a line on a rebuilt 2.7 out of a 1977 911S. It is 100% complete including the full CIS system. What kind of power loss would I experience if I stripped off the CIS and went with carbs? The motor is only 165hp to begin with... Thanks! Scott S |
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| Cupomeat |
Jul 2 2009, 03:21 PM
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missing my NY 914 in VA Group: Members Posts: 1,338 Joined: 26-November 07 From: Oakton VA Member No.: 8,376 Region Association: MidAtlantic Region |
I cannot support the following with empirical evidence, BUT;
I would say that you would not lose any peak hp with the switch. You will probably lose a little driveability as the CIS gets you a feedback Lamba circuit (correct me if it doesn't have a O2 sensor) and is more flexible for all kinds of weather. Also, CIS has a large plate (Read: Restrictor) in the airflow which controls the amount of fuel in the fuel distributor and this has an impact on the pumping losses and efficiency of the engine. All in all, I'd think you could get about the same peak HP. That being said, I'd stick with the FI as it will be a better car to drive. |
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Posts in this topic
Scott Schroeder 2.7 CIS to Carbs - how much HP loss? Jul 2 2009, 03:15 PM
brant Scott,
I heard about that motor
seemed like a re... Jul 2 2009, 03:20 PM turboman808 From what I have seen on graphs you get peaks and ... Jul 2 2009, 03:46 PM carr914 I would think that you would H.P. & Torque wit... Jul 2 2009, 04:43 PM 9146986 Why not just keep the CIS? Jul 2 2009, 10:11 PM pcar916 When I bought my car it had a 2.7L motor built up ... Jul 2 2009, 11:13 PM GeorgeRud If you don't have it, I would get Bruce Anders... Jul 2 2009, 11:29 PM ahdoman If the CIS is intact and working stick with it. Yo... Jul 3 2009, 12:10 AM carr914
When I bought my car it had a 2.7L motor built up... Jul 3 2009, 06:15 AM
pcar916
[quote name='pcar916' post='1188039' date='Jul 3 ... Jul 3 2009, 07:45 AM Project 6 Wayne at Pelican claims to have installed a CIS mo... Jul 3 2009, 07:50 AM J P Stein I know a few folks that run Webers on an otherwise... Jul 3 2009, 08:51 AM Gint I'd probably just use the CIS. But if you buy... Jul 3 2009, 08:53 AM scotty
I know a few folks that run Webers on an otherwis... Jul 3 2009, 10:28 AM naro914 I have a 2.7 in Huey at the moment, with Webers. I... Jul 4 2009, 10:56 AM Mountain914 Just want to throw this out there - since the titl... Jul 4 2009, 11:44 AM J P Stein
Just want to throw this out there - since the tit... Jul 4 2009, 01:38 PM ArtechnikA
A good illustration of the possibilities of the 2... Jul 4 2009, 02:02 PM J P Stein
A good illustration of the possibilities of the ... Jul 4 2009, 04:02 PM ArtechnikA
Yeah,yeah, some folks go all gaga over the MFI se... Jul 4 2009, 05:31 PM naro914 This is a good discussion....
I have carbs. I lik... Jul 4 2009, 04:14 PM J P Stein
This is a good discussion....
I have carbs. I li... Jul 4 2009, 07:12 PM 9146986 As long as the carbs are optimized for the engine,... Jul 5 2009, 11:18 AM |
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