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Straight Forward Plan: Swap an Ecotec Engine into a FB, keeping front end suspension parts "stock".
Ecotec's make between 160 and 180 hp, Similar amounts of Torque. Readily available parts all over the place, support for Turbo/Supercharger from Cobalt Forums.
Technically this engine was offered in the Solstice/Sky in a longitudinal RWD setup. If you are doing a swap for a street car this is likely the way to go.. Since we will be racing, Spare parts are easier to find/cheaper if you use the Miata Transmission.
Total Swap will likely cost about 3k to do.
Parts List (To Be updated throughout Build):
2.4 EcoTec "LE5" - Craigslist in Michigan, $650$ w 70k miles.
2.4 Ecotec Engine Controller (HHR, Pontiac G5, Cobalt, Saturn Sky, Pontiac Solstice) ($$Included in engine sale$$)
NA or NB Miata Transmission (5 Speed NB Recommended)
EcoMiata Bellhousing Adapter Plate
EcoMiata Flywheel Adapter
NA/NB Miata Flywheel (Doesn't need to be ultra lightweight) with matching Clutch "Stage 1" for ~ 180 hp.
4:10 Rear gear for FB (Allegedly you can use a Miata ring gear)
You know that you can install the RX7 tailshaft housing on the Miata transmission and have it bolt right into the car. I am running a Miata center transmission section with an RX7 bell housing, and tailshaft housing, the closer ratios really help.
Hi All, Thanks for the feedback so far.
Cost of Engine = 650 Bucks, 60k miles.
Today, picked up two Ecotec LE5 engines out of a 2010 and a 2012 Malibu. The Harnesses and fuse boxes were intact, and the basic measurements of the engine look like it will take up a significant amount of longitudinal space and height in the FB engine bay. I will post a few photos with the exact dimensions.
This is going to force us to move the Radiator forward ~ 5 Inches. Modification of the Rad Shroud, should allow us to still use the stock radiator, and still get decent air flow.
This can get confusing - In order to use the miata transmission gearset on a rotary, you would need to have the input shaft modified, and install the gearset into a FB transmission case.
What we're talking about here is different. He is going to use a Miata transmission, on an ecotec engine and put it in an FB. To make things go easier, he can use the tailshaft housing (back section, with shifter tower on it) from an FB trans, and bolt it onto his miata trans without modifying the Miata trans. This will allow him to easily bolt the transmission into an FB using an FB transmission mount etc. It would also allow him to use an FB driveshaft.
Again, the input shaft on the Miata trans would only need to be modded if you're wanting to use the miata gears behind a Rotary.
I'm very interested in watching the progress on this. I've been on the hunt for a cheap engine to swap into my drift car so I can keep the rotary as a spare for my street FB cars. My wife used to have a cavalier and I can attest to the Ecotec's longevity
My only reservation with using a Miata gear box would be strength. Several of us have killed them behind street ported rotaries. Which is a higher HP engine with no torque. The Ecotec would have torque.
What about a GM trans out of a Sky/Solstice?
If you do the Miata box with the RX7 tail shaft housing, you need the housing and the shift rail out of the RX7 transmission.
You can use the Miata rail and shifter turret on the RX7 tail shaft but there is some machine work required and it moves the shifter forward about an inch in the car. I currently have an RX7/Miata transmission with the Miata shifter turret on it in my race car. It shifts allot better than an RX7 box.
Hi All, Thanks for the feedback so far.
Cost of Engine = 650 Bucks, 60k miles.
Today, picked up two Ecotec LE5 engines out of a 2010 and a 2012 Malibu. The Harnesses and fuse boxes were intact, and the basic measurements of the engine look like it will take up a significant amount of longitudinal space and height in the FB engine bay. I will post a few photos with the exact dimensions.
This is going to force us to move the Radiator forward ~ 5 Inches. Modification of the Rad Shroud, should allow us to still use the stock radiator, and still get decent air flow.
have you gotten anymore work done on this? is the engine in the car?
Right now, I am working on a wiring harness layout (Diagram and actual harness) for the car and getting the 12A out and sold- to fund the adapter parts.
Allegedly the NA/NB 5 Speed Transmissions will hold more than 220+ hp and about 200 ft lbs without destroying themselves, based on my Miata friend's Knowledge.
Theres currently a team called "Apocalyptic racing" in Lemons, who run a 2.2 Ecotec in a old Celica. They were the ones who suggested the Eco-Miata swap kit. I think they get a new trans around every season, but I have seen them lose gears before.
The Sky/Solstice Transmission is significantly more expensive. If I were doing a street car, The I would just use that GM trans. Since its endurance racing, Its ultimately lower cost for the long run to use the Miata 5 spd since they are quite cheap.
We have reviewed the OE Ecotec Oilpan vs the stock Rx7 subframe. Ecomiata also sells a oilpan which is super low clearance and comes baffeled but its damn expensive at about 700$$$?!!?!
The Ecotec uses a front sump in an aluminum pan. It will be difficult to Baffle, but I do know some good welder buddies who will do it for a 6 pack of craft beer.
I believe we will have enough room to run it, if you flip the subframe backwards, similar to what guys do with the granny's speed shop 5.0 swap. See the detail on the link attached.
Update, The car is running and moving under its own power!
Latest steps have been finishing the exhaust, vacuum line routing, and diagnosing some issues with starters.
For the cooling system, we ended up running an the Rx7 Radiator (we have a aftermarket-ebay 3 core).
- We flipped the rad upside down to use shorter hoses, and added a in-line filler and cap.
- The hose coming from the back of the engine, around the bell housing and up to the radiator is still at least 2.5 ft long!
Using the Rx7 subframe, and our Eco-miata adapter for a 94 Miata transmission, The Prop Shaft was custom made at 40- 5/8 "
We chose to use a 4.77 Rear Gear from a Honda S2000, this put our top speed at about 135mph with a 225/45R15
Looks good with the Ecotec in, Needs some modification to hood to fit.. This is the side exit exhaust. Had to oval the pipe around the side to pass the frame rail. Very simple routing, similar to stock past the trans. 4.77 R&P from a Honda S2000 fits right into the Rx7 rear diff.
This is a mock-up for the Ute style rear end! This covers the fuel cell for rules. This is a cage we made for the fuel cell. Its pretty simple. We used foam-3M tape on the edges that touch the cell to make a tight fit. Here the cell is, with the spare tire tub cut out. In Hindsight it would have been better to have the attachment points horizontally across the car, but this worked out too. Breather, Pump and Return all wired up. We put a Summit- brand fuel pump in the stock location for the Rx7. Filter is in line.
