1988 Chrysler Conquest Ecotec Swap

Hey everyone, long time lurker, very infrequent poster. I have a project I'd like to share with the class. It's not at all motorsports-related, but GRM people are my kind of car people, and this forum seems like a great place to post a build thread. I've done several car projects in the past, and some of them have been large enough to qualify as "builds", but I've never posted a build thread before. My excuse has always been that I would rather spend as much time as possible actually doing the project (and as I get older, that time has become more and more valuable). Over the past few years though, I've watched Facebook, Instagram, and other forms of social media start to slowly choke the life out of forums. I think that's a shame. Social media is fast and convenient compared to forums, but objectively a worse way to tell a story, and especially to have that story archived for years. I've enjoyed so many others' build threads in the past, and I hate the idea of all that information just getting lost or hidden in the vast depths of social media. So for this project, I am determined to engage in that old pastime, the forum build thread. I hope some of you enjoy it, and I look forward to having the knowledge of the GRM community along for the journey, which I'm sure will make my project better.

Anyway, enough with the long-winded introduction, here's the car:

And here's the engine:

We're a couple months behind on progress, so I'll post updates to catch up to the current day as time allows. Thanks for following along!

mmmmm Conquest. One of my early childhood dream cars. Still haven't knocked one off the list, may need to rectify that situation....

Ecotec should be a fun swap, do carry on!

Lines on those has them as one of my favorites, and I have a pair of wheels in my basement waiting for the right car to go on! Looking forward to reading about /watching this.

I have wanted a conquest/starion since the 90’s. I’m excited to see this build. 

Oh this should be an interesting swap! 

Funny everyone wants a Conquest but I've been trying to give mine away for free for a year lol

yupididit said:

Funny everyone wants a Conquest but I've been trying to give mine away for free for a year lol

Hahaha..wait, WHAAT?!!!!

Thanks guys! Here's a little more history...

I bought this car last fall down in Indiana and drove it 500 miles home to Minnesota the next day. I was supposed to drive it home the same day, but in true Conquest fashion, it stranded me immediately after I bought it. I wrote up that whole story on the StarquestClub forum, so instead of re-writing it here, I'll just link to it.

This is my second one of these cars, and I know my way around them a little bit. One thing I know I don't want to keep long-term is the old G54B engine. I could go through it and modernize it, replace the old '80s computer and TBI with Megasquirt and MPFI, but the jet valves and balance shafts are still liabilities, and the cylinder head design is just not that good. Sure, all of those problems have solutions, but at this point, I'd rather just start over with something modern.

I considered a bunch of swap possibilities. To start, this car MUST have an inline engine. No V-anything. My last project was a twin turbo LS, and I over-engineered it. That just about burned me out; I am tired of buying things in pairs and packing too much stuff into too little space. This one has to be clean and simple. Air goes in one side of the engine and out the other. Easy to work on. Of course, it also still has to be turbocharged. This car's entire identity, down to the lettering on the automatic seatbelts, is TURBO, and I don't want to change that.

I looked at the 4G63 and more modern Mitsubishi engines, Ecoboosts, Volvo inlines, the GM Atlas family, Toyota JZs, and vetoed them all for various reasons. The two best candidates I found were the Honda K series and the Ecotec. They're both modern, light, common and cheap to get started with, multiple options to adapt to RWD, and have decent aftermarket support (probably a little more so for the K). There seem to be fairly well proven recipes to make 350-400HP with both of them without a lot of aftermarket parts. In the end, I chose the Ecotec because I have a lot of experience with GM vs. berkeley-all with Honda, and I already own HP Tuners, so the learning curve to tune it will be a little less steep. The Ecotec has a more front-sump oil pan design too, which looks like it will fit well in this rear-steer car. Oh yeah, and as far as I know, it's never been done before. I'm a sucker for that.

yupididit said:

Funny everyone wants a Conquest but I've been trying to give mine away for free for a year lol

Everyone wants a Conquest until it's time to do Conquest things? Seriously though, StarquestClub, Facebook groups, you'll move it, even if it's just to one of the guys who continuously part these cars out.

In reply to obsolete :

I used to frequent the starquestclub, I really don't like dealing with them anymore. Probably why I went from 3 to just this 1 Conquest (which was actually my first one). I'll probably never own another unless it's a flatty technica that talks to you. 

Another step toward the present day...

Having decided on the Ecotec, I started figuring out how and where I was going to get the parts. I think the ideal way to do it would be to buy a totaled Solstice/Sky and part it out. That way I could get everything I would want, with all the wiring and computers and misc. little bits for RWD all at once. I didn't want to have another dead car sitting around though, and I wasn't interested in spending the time to fully part one out to get my money out of it.

So, that left another option, which as a former LeMons racer and occasional automotive masochist, is my favorite: the U-Pull junkyard. The nearest one is about 45 minutes away, and they post pictures of their new inventory daily on Facebook, with VINs available on their website. A great thing about the Ecotec (true for the K series as well) is that it's right at peak junkyard availability. Piles of old Cobalts, HHRs, G6s, and other crappy 10-15 year old GM cars are showing up in junkyards every day, and most of them have Ecotecs in them. I started checking the U-Pull inventory every day for good donors.

I decided from the start that I wanted the 2.4L LE5 engine. I quickly learned by checking VINs that most Cobalts and HHRs came with the less-desirable 2.2L. Apparently the 2.4L was an extra-cost option that few people went for. G6s are a better bet because the 2.4L was the base engine in those. The early LE5s from '06-'07 are the most desirable, because they came with stronger rods than '08+. Anecdotally, the later rods should not be trusted at 300HP, but the early rods are good for 400HP.

So, I kept waiting for a good donor to arrive. I figured I'd wait until just the right car showed up, when the weather was nice, and get a couple friends together and have a fun day at the junkyard. Then a pandemic happened, and my plans changed from working with a group of friends to doing everything myself. Less fun, but still possible. Finally, in July, on a day that was a little hotter and sunnier than I'd hoped for, this appeared:

A 2007 Pontiac G6 SE, RPO LE5, and best of all, crashed hard. I wasn't going to waste my time pulling an engine at U-Pull from a car without visible body damage, the general rule being that if it's at the junkyard but the body is clean, it's there because the engine is blown. I'm pretty sure this one drove all the way to the pole that it hit.

Are you going to do a solstice AR5 or a colorado AR5 with the solstice bellhousing? 

Awesome awesome awesome build. And I've looked up the costs to get yup's free car to me multiple times. 

Thousand plus unfortunately

Somebeach (Forum Supporter) said:

Are you going to do a solstice AR5 or a colorado AR5 with the solstice bellhousing? 

Sorry to be a tease, but transmission plans are a couple posts away, please hold on just a little longer!

Okay, another update, lots of pictures in this one...

The G6 hit the yard on a Thursday, so the following Saturday morning, I packed up tools, my tube of Star Wars sunscreen, and a little styrofoam cooler with food and cold drinks. The yard did not allow the angle grinder since it has the potential to create sparks, but the sawzall was okay.

Here comes the nerdmobile...I hooked my Harbor Freight trailer up to my Chevy Volt and hit the road.

There she is. The only difference between the picture from Facebook and how I found it is that someone had already removed the hood for me and raided the fuse box. Everything else was still there.

Cutting the bumper beam off and pulling the radiator out of the way made access to the front of the (nasty Minnesota salt encrusted) engine really easy.

Wow, this thing got hit hard enough to break an engine mount! And yet, the air bags didn't deploy.

A couple hours of labor in the hot sun later, the engine was free. Pushing that A-frame across the yard by myself was the highlight of my afternoon...

I originally had big plans to also pull the wiring harness, ECM, BCM, RCDLR (keyless entry), and everything for electric power steering, but by the time I got the engine out, I had run out of water (didn't pack enough) and was too tired and dehydrated to keep working. The wiring harness was also damaged in the crash. Some wires were chewed up and one of the ECM connectors was broken; salvageable, but I could do better. So I just loaded the engine up in a wheelbarrow and headed to the checkout counter.

After I paid $129 plus a $35 core (plus extra for the alternator and ignition coils, which were apparently not considered part of the engine, though a lot of other stuff was) a nice junkyard employee loaded it up in my trailer for me.

A complimentary junk tire was also included. Good customer service!

Got it home safely.

And into the garage for teardown.

ECOTEC SWAP........got my attention......why no LHU (turbo)?

I like fwd engines adapted to rwd and stuffed in places they don't belong!

Ill be watching.

Thanks guys!

Somebeach (Forum Supporter) said:

Are you going to do a solstice AR5 or a colorado AR5 with the solstice bellhousing?  

759NRNG (Forum Partidario) said:

ECOTEC SWAP........got my attention......why no LHU (turbo)?

So, the answer to "why not a turbo block" and my plan for the transmission are related...let's go ahead and get into that now.

I chose the LE5 for several reasons:

1. Cheap! It's true that the turbo engines are dropping in price; you can get an LHU for $1k if you shop around, but I could still buy several more LE5s for that money. My time is not worthless, and I don't want to get stuck in a loop of repeatedly blowing up and swapping engines, but the LE5 will get me on the road now, and it will make enough power for me. After the swap is done and drivable, I can put the money I would have spent on a turbo block toward building up a stronger 2.4L based on an LEA or LAF block with forged rods and pistons that will be able to handle more power than a factory turbo bottom end would, and have it ready to go if/when I get tired of the LE5 or something happens to it.
2. I like the displacement. Torque is good, and the 2.4L will make more of it at lower RPM than a 2.0L and will have an easier time spooling a bigger turbo.
3. The LE5 uses port injection, but all turbo blocks are direct-injected. I know direct injection has advantages, but I am more comfortable and familiar with port injection, and I find it easier to modify and tune.
4. Finally, the transmission part. The LE5 crank has a 6-bolt pattern for the flywheel/flexplate. The turbo engines all have 8-bolt cranks. Why would that matter? Well...

This exists: https://transmissionadapters.com/collections/ecotec/products/olds-alero-naturally-aspirated-to-chevy-750r4-350-400. While that kit is primarily advertised for adapting to automatics, it can also be used to adapt to a manual transmission, and says as much in the instructions. After bolting on the bellhousing and crank adapters, the Ecotec becomes dimensionally identical to a SBC, which opens up a whole world of aftermarket possibilities, namely:

1. A bigger clutch. The Ecotec clutch disc is 9.5" diameter, which isn't terrible, but when you start making more power, you start needing heavier pressure plates and/or grabbier discs. This is primarily a street car, and I don't want the clutch to be annoying. I have done the "aggressive clutch on the street" thing and got tired of it pretty quickly. By adapting to the SBC pattern, I can add a bunch more surface area to the clutch with a basic 153T flywheel and 10.5" disc, or even go all the way to a 168T flywheel with a 11" disc if I want to really max it out. Those clutches will hold up to more power than I will ever make, while keeping a smooth-engaging, full-faced sprung organic disc and reasonable pedal pressure.
2. More transmission options. The AR5 is fine but nobody really raves about it. The ratios are pretty wide, but it's decently strong, it shifts decently well, and it's pretty cheap. If it would fit easily in the car, I would probably just go with one. But...

The AR5 won't fit easily in the car. It's about the same size as its older relative, the R154, which is commonly used with JZ swaps. Manual Starquests have very narrow transmission tunnels. The automatics actually have a different floorpan with a wider tunnel and are preferred for swaps, but mine is a factory manual car with the narrow tunnel. At a minimum, fitting a transmission the size of the R154 requires cutting out one of the two layers of steel in the tunnel, then heating and hammering the remaining layer. Some people just cut out the whole tunnel and build a new one (that surgery is mandatory to fit a T56; no amount of heating and hammering will get it in).

I don't want to cut up the body, and there's only one other transmission option that is proven to fit the tunnel without any modifications: a T5. Sure, they're ancient technology at this point, and not exactly the strongest, but a world-class T5 should hold up okay since I don't plan on making many trips to the drag strip. So, that was my plan, until Tremec did this: https://www.tremec.com/menu.php?m=183. "You're going to buy a $2,800 transmission for a $200 engine? Are you insane?" I mean, yeah, but also, it looks perfect. It checks every box. My budget for this project doesn't limit me to only using junkyard parts; I could buy it if I want to. And unless a great deal on a WC T5 comes along, I probably will.

So, there you go. I will wait for the comments...

Pretty interesting.  I didn't know there was an adapter for ecotec to T5. That's why I love reading these build threads. Always so much to learn. 

How much time does a $2,800 transmission solve? If it gets the project wrapped up sooner, and ticks all the right boxes, then it truly is the correct answer. 

Too many times saving that dollar costs you months in engineering and stalled projects. Priorities,  man.

obsolete said:

Thanks guys!

Somebeach (Forum Supporter) said:

Are you going to do a solstice AR5 or a colorado AR5 with the solstice bellhousing?  

759NRNG (Forum Partidario) said:

ECOTEC SWAP........got my attention......why no LHU (turbo)?

So, the answer to "why not a turbo block" and my plan for the transmission are related...let's go ahead and get into that now.

I chose the LE5 for several reasons:

1. Cheap! It's true that the turbo engines are dropping in price; you can get an LHU for $1k if you shop around, but I could still buy several more LE5s for that money. My time is not worthless, and I don't want to get stuck in a loop of repeatedly blowing up and swapping engines, but the LE5 will get me on the road now, and it will make enough power for me. After the swap is done and drivable, I can put the money I would have spent on a turbo block toward building up a stronger 2.4L based on an LEA or LAF block with forged rods and pistons that will be able to handle more power than a factory turbo bottom end would, and have it ready to go if/when I get tired of the LE5 or something happens to it.
2. I like the displacement. Torque is good, and the 2.4L will make more of it at lower RPM than a 2.0L and will have an easier time spooling a bigger turbo.
3. The LE5 uses port injection, but all turbo blocks are direct-injected. I know direct injection has advantages, but I am more comfortable and familiar with port injection, and I find it easier to modify and tune.
4. Finally, the transmission part. The LE5 crank has a 6-bolt pattern for the flywheel/flexplate. The turbo engines all have 8-bolt cranks. Why would that matter? Well...

This exists: https://transmissionadapters.com/collections/ecotec/products/olds-alero-naturally-aspirated-to-chevy-750r4-350-400. While that kit is primarily advertised for adapting to automatics, it can also be used to adapt to a manual transmission, and says as much in the instructions. After bolting on the bellhousing and crank adapters, the Ecotec becomes dimensionally identical to a SBC, which opens up a whole world of aftermarket possibilities, namely:

1. A bigger clutch. The Ecotec clutch disc is 9.5" diameter, which isn't terrible, but when you start making more power, you start needing heavier pressure plates and/or grabbier discs. This is primarily a street car, and I don't want the clutch to be annoying. I have done the "aggressive clutch on the street" thing and got tired of it pretty quickly. By adapting to the SBC pattern, I can add a bunch more surface area to the clutch with a basic 153T flywheel and 10.5" disc, or even go all the way to a 168T flywheel with a 11" disc if I want to really max it out. Those clutches will hold up to more power than I will ever make, while keeping a smooth-engaging, full-faced sprung organic disc and reasonable pedal pressure.
2. More transmission options. The AR5 is fine but nobody really raves about it. The ratios are pretty wide, but it's decently strong, it shifts decently well, and it's pretty cheap. If it would fit easily in the car, I would probably just go with one. But...

The AR5 won't fit easily in the car. It's about the same size as its older relative, the R154, which is commonly used with JZ swaps. Manual Starquests have very narrow transmission tunnels. The automatics actually have a different floorpan with a wider tunnel and are preferred for swaps, but mine is a factory manual car with the narrow tunnel. At a minimum, fitting a transmission the size of the R154 requires cutting out one of the two layers of steel in the tunnel, then heating and hammering the remaining layer. Some people just cut out the whole tunnel and build a new one (that surgery is mandatory to fit a T56; no amount of heating and hammering will get it in).

I don't want to cut up the body, and there's only one other transmission option that is proven to fit the tunnel without any modifications: a T5. Sure, they're ancient technology at this point, and not exactly the strongest, but a world-class T5 should hold up okay since I don't plan on making many trips to the drag strip. So, that was my plan, until Tremec did this: https://www.tremec.com/menu.php?m=183. "You're going to buy a $2,800 transmission for a $200 engine? Are you insane?" I mean, yeah, but also, it looks perfect. It checks every box. My budget for this project doesn't limit me to only using junkyard parts; I could buy it if I want to. And unless a great deal on a WC T5 comes along, I probably will.

So, there you go. I will wait for the comments...

thank you .....that was what i was looking for ....still following along ........late

In reply to obsolete :

The transmission from the 240sx and 300zx fits in the transmission tunnel. They can take bit of abuse too. 

yupididit said:

In reply to obsolete :

The transmission from the 240sx and 300zx fits in the transmission tunnel. They can take bit of abuse too. 

For the 240sx transmission, you mean the 5-speeds that came behind SRs/KAs? I forget what those are called but yeah, they definitely look like they would fit. I always thought they were fairly fragile. For the 300ZX transmission, you talking about the Z31 NA transmission? The Z32 transmissions are pretty beefy. The Z31 turbo transmission is a T5 :)

I like the Starion (and thus Conquest but those were never marketed here in Sweden), cool thing.

I'd be interested to hear when/if you go for the TKX, and how close it is dimensionally to a T5. I run a T5 in my Capri and have some issues. It looks like the TKX could be one solution, as long as a T5 (Ford bellhousing would mount up to it). The TKX might also be an option for my next project. Maybe I'd get a discount if I buy two at the same time? ;-)

Gustaf

therealpinto said:

I like the Starion (and thus Conquest but those were never marketed here in Sweden), cool thing.

I'd be interested to hear when/if you go for the TKX, and how close it is dimensionally to a T5. I run a T5 in my Capri and have some issues. It looks like the TKX could be one solution, as long as a T5 (Ford bellhousing would mount up to it). The TKX might also be an option for my next project. Maybe I'd get a discount if I buy two at the same time? ;-)

Gustaf

Thanks! American Powertrain has some renderings from Tremec showing the TKX overlaid on the TKO and T5. Anywhere the TKX is larger is in green, anywhere the other transmission is larger is in blue: https://americanpowertrain.com/the-all-new-tremec-tkx-is-here/. The TKX is definitely wider around the midplate area. As long as that fits, the rest seems like it would be okay.