DOHC 2.0 Conversion; What Do You Think?

[Hasbro]

I'm in negotiations with a fellow member here to acquire a former track car. It's a wonderful opportunity and am really looking forward to turning it into a very light street/track days car. The X is dismantled a good bit and there are the necessary parts for a Beta twin cam conversion. I hadn't considered this conversion and was initially interested in a Honda B or K project but I like what the end results could be. The Lancia 2.0 wouldn't have as much hp but this is going to be a very light car. And HEMI X would be such a cool plate.

I've come across some positives and negatives regarding this conversion and wanted to here from those of you that have experience or knowledge with such a project. I understand it can get "VERY PRICEY and can be a LOT OF WORK," to paraphrase Guy Croft. What thoughts dost thou have?

 

[Mechanogeek]

I would always ask the following questions

"how much power do you anticipate getting from the conversion"
Power usually translates to money. Will you get enough power to make the conversion worthwhile?

"How much cutting will it require"
K20 mod requires a LOT of sheetmetal cutting and welding to accomodate

"What additional components will require replacements to match"
like with the K20 mods, you need to replace the transmission and a bunch of peripherals like the shift linkage and etc
Would the beta twin cam require transmission replacement and shift linkage mods as well

"What other compromises will it entail"
Do I need to lose the passenger seat?
If you have A/C, and want to keep the A/C, will you be able to?

"How difficult will it be to support"
Are maintenance and repair parts easily (and affordably) available?

All that being said, you cannot put a price on the cool factor. If I could get my hands on a Lancia V6 and get that stuffed in the engine compartment, I'd probably decide to do it if I could afford it regardless of the answers to above questions.

 

[Dr.Jeff]

I'm guessing the Honda swap is a little more work and expense, but offers a lot more performance potential and reliability. Also consider the whole project; trans, suspension, brakes, chassis, cooling, controls, electronics, etc. Regardless of the choice of engines it will be costly and very labor intensive.

 

[fastx19]

The technical pace around engines has really moved over the last 15 years. We now have 4 cylinder engines putting out 300+ hp in normal tune. 2015 Mercedes GLA 45 (355hp), 2016 Volvo XC90 2L (316hp), 2015 Ford 2.3L EcoBoost (310hp) and so on. Heck, even the 2015 Ford Focus ST 2L is 252hp in stock tune. I think it comes down to what you want. Tons of power and reliability? Good power increase but keeping the heart Italian? Just enjoy the sounds of Carbs? These is no wrong decision, just what you believe you want the most.

 

[Hasbro]

Power: I'm considering 150 whp as a target. I don't know what that entails cost-wise.

Cutting; I'm prepared to cut for a Honda so that's ok. Plus, no trunk and moving the tank to the frunk are a given. I don't know if cutting for the tc is any less or more.

Additional components; as I understand and correct me someone if I'm wrong, the Scorpion transaxle, axles, suspension, brakes, etc., can be used. This is huge to me.

Compromises; I don't think the passenger seat would be removed but I'm ok with that, anyway. Don't care about ac.

Support; don't know.

I do like the cool factor and keeping the pieces/parts in the family. Any conversion is spendy so if it's viable...

 

[Hasbro]

I'm guessing the Honda swap is a little more work and expense, but offers a lot more performance potential and reliability. Also consider the whole project; trans, suspension, brakes, chassis, cooling, controls, electronics, etc. Regardless of the choice of engines it will be costly and very labor intensive.

The reliability is a big factor, admittedly. If the Honda is more work I'm encouraged with trying the tc.

The technical pace around engines has really moved over the last 15 years. We now have 4 cylinder engines putting out 300+ hp in normal tune. 2015 Mercedes GLA 45 (355hp), 2016 Volvo XC90 2L (316hp), 2015 Ford 2.3L EcoBoost (310hp) and so on. Heck, even the 2015 Ford Focus ST 2L is 252hp in stock tune. I think it comes down to what you want. Tons of power and reliability? Good power increase but keeping the heart Italian? Just enjoy the sounds of Carbs? These is no wrong decision, just what you believe you want the most.

I'm not out to create a 5 lbs. per hp monster and really don't want that. Been there, done that, still alive to tell lies. 10 to 12 lbs, is my goal for this project. If I went Honda I'd go K24 frank but 12/1 is fine. And with the Honda I would build a more refined street car. I'm actually shooting for well under 1800 lbs but will design for 1800. Anything under is gravy.

So far, no one is scaring me away. I do wish there was more tech support similar to the K.

 

[Pete Whitstone]

Additional components; as I understand and correct me someone if I'm wrong, the Scorpion transaxle, axles, suspension, brakes, etc., can be used. This is huge to me.

Well, kind of. The Scorpion transaxle or the Beta Coupe transaxle could be used. Since you will probably have to go to a cable shifter, the difference between them (linkage input on the front or the back) is probably a moot point. The Scorpion originally used a complicated rod linkage that would be difficult to replicate into an X.

X1/9 suspension and brakes are all compatible with this conversion, no need to use the actual Scorpion parts there. The only real difference is 38mm brake pistons on the rear of the Scorp, vs 34 on the X. So the Scorp brakes are a mild upgrade, but they are hard to find and generally expensive if you can find them.

As far as the axles, the Scorp axles would bolt on either end, but the Scorp being a wider car, would end up too long. What I have always heard (and I'd be interested to hear someone else verify it) is that you use the Beta (or Scorp) transaxle, plus the funky little Beta drive shaft that runs down the length of the DOHC engine, and then on either end you use the short side X1/9 shafts. That makes the right width for installation in an X.

Pete

 

[Hasbro]

Thanks for the clarification. Feeling pretty positive about this.

DDavidV wrote an article about a guy who built a 2.0 tc. Hoping he hops on here. I heard back from a supplier that was less than enthusiastic but they also offer other options. Also, I believe Old Fiat Guy has one he races/raced?

 

[Steve Hoelscher]

Other than the axles I don't see the Scorp/Beta swap being much easier or cheaper than some other options. I would note that the Fiat/Lancia 2 liter is a significantly heavier engine than most modern aluminum block options. And getting 150 WHP from that engine would take a decent build.

And just as a note on perspective: My DP MR2 makes about 150 WHP and weights under 1700 lbs. For a track car you will likely find that 150 whp would leave you wanting more. To go to the effort of a swap to net 150 whp seems a little miss-directed. Going from 150 to 200 is quite noticeable. There are lots of options that can get you into the 200 whp range and don't require you build the engine to net that. A stock Honda K series or a Toyota 2ZZ with both get you in that range. The engines are lighter than the twin cam and are likely easier to live with.

 

[Ulix]

If I went through the trouble of swapping powertrains, I would go for one with a lot of character, one that revs like crazy, sounds great, and is just plain awesome all around.
The DOHC powertrain (to me) is not one of those. It is fine when it came in the car from the factory, but it is not so awesome that I would pick it if I had the choice.

VTEC would be fun I guess, but I don't know modern japanese drivetrains well enough to make a choice.

 

[lookforjoe]

The other issue to consider with any newer powertrain is the EMS. All the newer cars that make nice HP off the bat do so with sophisticated EMS. No practical way to use 99% of those (refer to TonyK's Abarth conversion). That means standalone/ aftermarket EMS has to be factored in from the start. That seriously limits what options you really have, I believe.

Honda swap makes sense since all the EMS is figured out & one can plug & play for a range of preset tune levels, unless I misunderstood.

If I wasn't looking to thread a proven path like the Honda install, I would lean towards Volvo powertrain, since the older (90's) M4.4 is fully tuneable, doesn't look beyond the 'normal' engine sensors for info, and I'm familiar with it. I guess that is what it boils down to, if you are going to DIY a conversion - what one is personally comfortable & familiar with, to a great extent.

I don't recall what the $$$$ are for the Honda EMS setup, can someone who's done it add a ballpark number?

 

[kmead]

From what I have heard and what I have seen of 124/125/132 based conversions they are not ideal in this application.

The Lancia Scorpion is basically already what you are looking to do and although there are some extremely nice and entertaining examples of them, ones with 150+ HP are rare on the ground. Getting to that kind of power is not an inexpensive undertaking with a Fiat twin cam without going to a turbo/supercharger.

If I wanted north of 130 hp I would be considering an alternative engine and it would likely be a more modern lightweight engine. Preferably one that has a large aftermarket and a proven record of delivering the power I am looking for without me having to do even further development work beyond just fitting the confounded thing and making it work.

That said, we all have our obsessions. My current object of desire is the Mazda V6 in its 2.0l incarnation as I love the sound (a Fiat/Ferrari Dino with the right intake approach) and it can look the part, particularly when unbridled from its ludicrous intake manifold. Besides that I love the story of the builder.

https://crapengineering.weebly.com/

 

[Steve Hoelscher]

If I went through the trouble of swapping powertrains, I would go for one with a lot of character, one that revs like crazy, sounds great, and is just plain awesome all around.
The DOHC powertrain (to me) is not one of those. It is fine when it came in the car from the factory, but it is not so awesome that I would pick it if I had the choice.

VTEC would be fun I guess, but I don't know modern japanese drivetrains well enough to make a choice.

^^^ This. To keep the car in character. A large displacement, low reving engine really doesn't do this. But then that's my taste and may not be yours.

I have had a long relationship with Toyota so I know much of their performance models well. When I was shopping for a daily driver and commuter car a few years ago I specifically searched for and bought this car:

Its a 2004 Celica GTS. Its easily the best handling fwd car I have ever driven but its the 1.8 liter DOHC VVTi (2ZZ-GE) engine that really makes this car. This engine is one of my favorites. Its rating of 190HP from 1.8 liters is an excellent power/displacement ratio and on par with the Honda K series. It has also proven to have remarkable reliability. I bought the car with 120K miles on it and it now has 230K, with no maintenance beyond routine service. It gets 30 mpg regardless of how I drive it.

The engine is significantly lighter than the 4AGE 1.6 in my MR2 and stock makes more power than the fully built (14:1) DP motor. The engine is a joy to drive. It pulls smoothly from idle all the way to the 8600 rpm fuel cut and it really sings when the VVT hits at 6500. I think this engine would be an ideal candidate for an X1/9 swap. Its also about half the cost of an Si K motor.

Another point. Like the K motors the wiring harness and ECU can be swapped into most anything and there is no manufacturer's CAN but needed for operation. I don't know of anybody that has put one in an X1/9 and there is certainly no kit so it would require fabrication. Given the 2ZZ engine layout I don't think much cutting would be required but I haven't made any measurements.

 

[JimD]

I have these pictures from Wayne taken many years ago when he was working on a twin cam swap on an X. Without descriptions, they probably have less value, but here they are.

I will do a quick search of the archives... if the search is working. Tapatalk was down the last few times I tried a search.

 

[MikeHynes]

I'm interested in this swap too. Mostly because I already have a DOHC engine and Scorpion trans. This is a swap that's been done many times before so new new ground would not be plowed here. There are many reasons to do something different, but those reasons don't help you make the swap - if that's what you want to do. There are some things that you need to consider before you move forward so if you decide to do this don't be afraid to ask for help.
I've attached a few pics that I've collected to illustrate some of the fabrication that's necessary. Not sure who's car this is, but I believe he is a member here. Hopefully he'll speak up?

 

[Old Fiat Driver]

Hi Mike, ya this is my car. The car is now dead and I have the complete drive train that I am getting ready to install into a rust free 74 X. The engine is a 2L 124 with a scorpion transaxle, big valve head, PBS B3 cams plus an exhaust cam that is 10 degrees shorter, Megasquirt FI, 4 throttle body intake, wasted spark being converted to COP wasted spark, 9.2 to 1 compression, and a few other goodies. The transaxle is 4.36 ring and pinion although I also have 3.90 and 3. 70 something, need to verify. The axles are 302 steel special made units and the it has a ZF limited slip. Also cable shifter that works great and am making an even better one. I just need to find the time to finish it.
Cheers
Charlie

 

[Dr.Jeff]

This may not be relevant to the decision of which way to go, but just an observation.
I recall the 'Fiat/Lancia twincam into a X' swap was a big deal back before the Honda swap became a 'thing'. It seems now that alternatives from other makes (e.g. Japanese drivelines) are being done - offering lighter weight, more performance, greater reliability, and roughly the same amount of work to install - the 'twincam in a X' notion is more a nostalgia item. For example if you wanted to create an accurate Abarth Prototipo clone it would be appropriate. Certainly nothing wrong with nostalgia; perhaps akin to some American hot-rodders still swapping in SBC's despite the LS engines being a better all around alternative (although this analogy might not be fair due to the obvious expense difference between those two engines). In the case of the X swap, unless you already have Scorpion (or similar) parts on hand, the expense is likely not much difference between the twincam and a Japanese engine. Nor the amount of work to do the conversion. So as someone already stated, it might come down to personal preference for nostalgia or performance.
As I said just an observation.

 

[Old Fiat Driver]

Pretty much right Dr. Jeff. As to the weight, although the Honda 2 liter is aluminum I am not sure it's any lighter than the 2L twin cam. I helped Alex build his Honda x19 and I can say the Honda engine is really heavy, it has a lot of complexity. We should have weighed them but that's history and it would be interesting if anyone has the actual numbers. Also the Honda takes up a lot of space and requires a lot of cutting in the engine compartment. I did cut into the spare tire compartment with my twin cam conversions but that is no longer necessary and can be done with a minimum of cutting if the right parts are used. No mater which way one goes room is precious but much worse with the Honda. As to power the modern engines are much better but a turbo completely solves that. 250 to 300HP or more is no problem with modern electronics. I have used several different turbos in the past with up to 25 PSI and you just can't put it to the ground. I finally had to bring the pressure down to 12 PSI to make it even drivable. Of course the twin cam doesn't rev like the Honda and takes big bucks to make it rev. I keep it to 7000 RPM with no problems.
Have a good one
Charlie

 

[Hasbro]

Wow, lot's of good feedback. The option of the available Lancia 2.0 and ancillaries for a generous and decent cost with the car seem attractive. I had never considered it before. I want to make this a very light weight car and I believe the Honda B (Similar to Steve's suggestion of the Toyota 1.8) is a top choice for what I'm thinking for this particular X. At least 75 lbs. lighter than a K, stock 180 hp and 9200 rpm is a nice way to start. I would also like to try a K24 in a more refined street car (Maybe a Scorpion) and the Lancia 2.0 has some similar traits. Sort of. And it is available.
Gotta run, back to work.

 

[Old Fiat Driver]

Ya Hasbro there a lot of ways to go. It just depends what you want and how much money and time you want to invest. The Fiat 2L will require some performance upgrades to make it quick where the Hondas are strong right out of the box. In my case I have everything for the conversion and the parts are in great shape. Just need to get dirty and finish it. The red car is the car I built it 1981 with the 2L. The car is gone so the drive train will go into the yellow one