Engine swaps, Mpg focused |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
Engine swaps, Mpg focused |
r_towle |
Jun 1 2022, 08:08 PM
Post
#1
|
Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Leave the SBC and flat6 conversions out of this.
Who has swapped a different engine into a 914? Something Japanese, great mpg? |
mepstein |
Jun 1 2022, 08:17 PM
Post
#2
|
914-6 GT in waiting Group: Members Posts: 19,518 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region |
My stock 1.7 would easily get 38-40 mpg on the highway at 70-75mph. Why bother with an engine swap. Just use a 1.7 in good tune and the right tires.
|
Robarabian |
Jun 1 2022, 08:35 PM
Post
#3
|
914 A Roo Group: Members Posts: 622 Joined: 11-February 19 From: Simi Valley, Kalifornia Member No.: 22,865 Region Association: Southern California |
When I am not hard on the Turbo, my Subaru 2.0 WRX motor does 30 MPG highway....
Its good around town, but my foot is always in it so hard to say how efficient it could be. |
Montreal914 |
Jun 1 2022, 08:57 PM
Post
#4
|
Senior Member Group: Members Posts: 1,675 Joined: 8-August 10 From: Claremont, CA Member No.: 12,023 Region Association: Southern California |
My stock 1.7 would easily get 38-40 mpg on the highway at 70-75mph. Why bother with an engine swap. Just use a 1.7 in good tune and the right tires. WOW! those are great numbers! (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/driving.gif) |
mepstein |
Jun 1 2022, 09:09 PM
Post
#5
|
914-6 GT in waiting Group: Members Posts: 19,518 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region |
My stock 1.7 would easily get 38-40 mpg on the highway at 70-75mph. Why bother with an engine swap. Just use a 1.7 in good tune and the right tires. WOW! those are great numbers! (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/driving.gif) My 2.0 with a hot cam and carbs was more like 25-28 |
r_towle |
Jun 1 2022, 09:29 PM
Post
#6
|
Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
I got 48 mpg from my tuned 1.7 with djet….and I really learned djet that year.
And I learned all about low roll resistant tires….which are great for mpg but suck for traction But I digress. Just curious if anyone put a newer FI engine like a Toyota or Honda into a 914 |
Dave_Darling |
Jun 1 2022, 10:20 PM
Post
#7
|
914 Idiot Group: Members Posts: 15,048 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
There's at least one VW turbodiesel out there. (Pre-TDI.) That would seem to be a great way to go for fuel economy, but I'd be concerned that the gearing would be too short to really do the diesel justice.
--DD |
cali914 |
Jun 1 2022, 11:23 PM
Post
#8
|
cali914 Group: Members Posts: 452 Joined: 26-April 06 From: Berkeley Ca. Member No.: 5,934 Region Association: Northern California |
I had a Honda J35 odyssey engine in my 914 210 hp getting 25 city and 30 highway. One of the smoothest engines i have ever swapped into a 914.
|
ogdougy |
Jun 2 2022, 12:01 AM
Post
#9
|
Newbie Group: Members Posts: 49 Joined: 9-May 22 From: Arizona Member No.: 26,536 Region Association: Southwest Region |
Why not ee20?
Subaru flat 4 - it fits Get it with the 6 speed trans - gearing good Diesel - gets 40+ mpgs in the Forester. Heavy and AWD. Imagine the numbers it could make in a 914 |
Arno914 |
Jun 2 2022, 12:29 AM
Post
#10
|
Member Group: Members Posts: 233 Joined: 13-May 20 From: near Frankfurt, Germany Member No.: 24,260 Region Association: Germany |
Just wondering. (IMG:style_emoticons/default/confused24.gif)
Does anybody really care about the fuel economy of his 914??? It is good, even to today´s standards and 914´s are so much fun to drive. So who cares about a mile less ore more on a tank? (Just my 2 Cents...) |
sb914 |
Jun 2 2022, 03:34 AM
Post
#11
|
Surf Guru Group: Members Posts: 4,365 Joined: 25-November 12 From: Brookings,Oregon Member No.: 15,191 Region Association: Southern California |
Just wondering. (IMG:style_emoticons/default/confused24.gif) Does anybody really care about the fuel economy of his 914??? It is good, even to today´s standards and 914´s are so much fun to drive. So who cares about a mile less ore more on a tank? (Just my 2 Cents...) (IMG:style_emoticons/default/agree.gif) |
mate914 |
Jun 2 2022, 05:09 AM
Post
#12
|
Matt Group: Members Posts: 782 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
Just wondering. (IMG:style_emoticons/default/confused24.gif) Does anybody really care about the fuel economy of his 914??? It is good, even to today´s standards and 914´s are so much fun to drive. So who cares about a mile less ore more on a tank? (Just my 2 Cents...) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) |
Front yard mechanic |
Jun 2 2022, 05:15 AM
Post
#13
|
Senior Member Group: Members Posts: 1,205 Joined: 23-July 15 From: New Mexico Member No.: 18,984 Region Association: None |
Just wondering. (IMG:style_emoticons/default/confused24.gif) Does anybody really care about the fuel economy of his 914??? It is good, even to today´s standards and 914´s are so much fun to drive. So who cares about a mile less ore more on a tank? (Just my 2 Cents...) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/agree.gif) We need two hundred and fifty 2 cents to buy a gallon |
Mayne |
Jun 2 2022, 06:36 AM
Post
#14
|
Member Group: Members Posts: 254 Joined: 28-February 17 From: NM Member No.: 20,880 Region Association: None |
What about an early 1.6/1.8 Miata motor?
|
Superhawk996 |
Jun 2 2022, 06:37 AM
Post
#15
|
914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
And I learned all about low roll resistant tires….which are great for mpg but suck for traction But I digress. Just curious if anyone put a newer FI engine like a Toyota or Honda into a 914 You're on the wrong track with an engine swap. You were on the right track with low rolling resistance tires. Fuel economy is a function of rolling resistance, aero dynamic drag, and parasitic drag. Aero drag is almost a fixed variable based on body shape. 914 is already surprisingly good with flat underbody, small frontal area, and small side mirrors, you'll largely need a wind tunnel to tweak it any further. Someone did a nice CFD on 914 aero. If you are serious about trying to improve MPG, you can't ignore aerodynamics. Here: http://www.cassidy-online.com/porsche914/a...aids/index.html Tire are ABSOLUTELY the the largest rolling resistance variable you can easily affect. Look at Honda Insight (165/65R14) - skinny, low rolling resistance tires. Sounds a lot like stock 914 tires. But notice, the Insight went 14". That is to reduce inertia of the wheels vs. stock 914 on 15". The larger diameter wheel requires more energy (i.e. lower MPG) to accelerate the wheel up to speed after each stop. You'll also want to keep wheel mass as low as possible (carbon fiber would be ideal (IMG:style_emoticons/default/laugh.gif)). Big meats that look cool and provide awesome handling aren't going to get good MPG. After that, you're chasing parasitic drag. Need to go to high roll back brake calipers (makes brakes feel crappy), low drag bearings and seals (differential, wheel bearings, etc.). The actual engine has very little to do with MPG other than it needs to overcome rolling resistance, aero drag, and parasitic drag. As noted by Mark as well as your own claimed MPG, a stock 1.7L driven gently is going to be pretty respectable. I'm curious if you got 48 mpg; what target MPG are you hoping for and for what purpose? How much gas could you buy with the money spent on the engine swap and/or pursuit of lowering parasitic loads? If you want more fuel efficiency out of an engine, you're going to end up looking at something like 1.0 - 1.2L, 3 cylinder turbo charged engines. The Mitsubishi Mirage 3 cylinder is 1.2L - about 76 HP. Sounds suspisciously like a stock 1.7L (IMG:style_emoticons/default/happy11.gif) but will have better Brake Specific Fuel Consumption than a 50 year old air cooled motor. Or, there is the Ford Fiesta 1.0L 3 cylinder EcoBoost that is good for 123 HP. But if you're on the turbo and making 123 HP, you won't be getting best fuel economy (IMG:style_emoticons/default/av-943.gif) and we're back to square one. Same for the 3 cylinder out of the Mini Clubman which is 1.5L and 134 HP. |
Superhawk996 |
Jun 2 2022, 06:43 AM
Post
#16
|
914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
What about an early 1.6/1.8 Miata motor? Nope. 1st generation Miata is roughly the same weight as a 914 (2,000 lbs ish), similar frontal area, etc. I had one from 1994 - 2018. About 30 MPG on highway, 24 MPG combined fuel economy per EPA. https://www.fueleconomy.gov/feg/noframes/7490.shtml A good portion of why the Miata MPG is so low is because of the tires. The messy underbody creating drag, and the poor aero drag due to the body design / convertible top shape don't help at all either. If you're serious about MPG, you're going to end up having to do the engineering and it's not as simple as just swapping engines. Note to tie into later post: 1st Gen Miata had a published Cd of 0.38 -- same as what I could find for the 914. |
bbrock |
Jun 2 2022, 07:25 AM
Post
#17
|
914 Guru Group: Members Posts: 5,269 Joined: 17-February 17 From: Montana Member No.: 20,845 Region Association: Rocky Mountains |
Just wondering. (IMG:style_emoticons/default/confused24.gif) Does anybody really care about the fuel economy of his 914??? It is good, even to today´s standards and 914´s are so much fun to drive. So who cares about a mile less ore more on a tank? (Just my 2 Cents...) YES! (IMG:style_emoticons/default/chair.gif) (IMG:style_emoticons/default/smile.gif) Fuel economy has always been a big draw for me since I fell in love with these cars in the 70s. Performance and (IMG:style_emoticons/default/stromberg.gif) mileage? Not interested (IMG:style_emoticons/default/dry.gif) Performance and great economy? Sign me up. (IMG:style_emoticons/default/piratenanner.gif) |
mepstein |
Jun 2 2022, 07:35 AM
Post
#18
|
914-6 GT in waiting Group: Members Posts: 19,518 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region |
I think good mpg is a good measure of engine performance. Just like our cars, doing more with less.
|
Superhawk996 |
Jun 2 2022, 07:36 AM
Post
#19
|
914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
(IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/slap.gif) (IMG:style_emoticons/default/av-943.gif) You can have both with a 914 -- respectable fuel economy but MOST importantly great handling. (IMG:style_emoticons/default/grouphug.gif) |
Chris H. |
Jun 2 2022, 07:37 AM
Post
#20
|
Senior Member Group: Members Posts: 4,043 Joined: 2-January 03 From: Chicago 'burbs Member No.: 73 Region Association: Upper MidWest |
Leave the SBC and flat6 conversions out of this. Who has swapped a different engine into a 914? Something Japanese, great mpg? This was Rich's the original question. If I had to do a different swap I would consider a K series with megasquirt. You could control the VTEC to keep the fuel economy up there but also kick it in early if you wanted some extra ooomph. |
Lo-Fi Version | Time is now: 27th September 2024 - 01:20 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |