fiatmonkey
Tim Hoover
opinions are great aren’t they?
Latest Project (#2)
- Thread starter fiatmonkey
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- box engine swap
darwoodious
Darin Nelson
Looks strong to me. The only (easy) thing I'd consider is adding some more fasteners to your "access cover" - it now carries a some of the twist/torsional load (rear bulkhead).
I really need to post some of my progress. Thanks for posting yours Tim.
(BTW: you're doing 2 more - you're certifiably crazy)
I really need to post some of my progress. Thanks for posting yours Tim.
(BTW: you're doing 2 more - you're certifiably crazy)
Steve Hoelscher
True Classic
Yeah, the strength of a structure is also determined by the load applied.
While the boxed cross section is the preferred shape the modification is likely adequate for the load.
Nice work by the way.
Incidentally, its likely been discussed previously, but the '74 was the weakest of the X's chassis.
fiatmonkey
Tim Hoover
Yeah, the strength of a structure is also determined by the load applied.
While the boxed cross section is the preferred shape the modification is likely adequate for the load.
Nice work by the way.
Incidentally, its likely been discussed previously, but the '74 was the weakest of the X's chassis.
Thanks Steve. I honestly think any welds you add to a 74 instantly adds more stability it didn't have before
Not pictured are some welds done to add rigidity to the strut tower to upper rear "cross member" (if you can call it that) at the top of the rear firewall to rear trunk. A welder friend was looking over my shoulder while I was working on the first swap project and he was shaking his head at the factory welds.
fiatmonkey
Tim Hoover
If I have added to any motivation for you then my work is done
I agree with Dan's comment too. How about putting in a 130hp Honda Fit 1.5l engine AND without all the metal cutting and intrusion into the spare tire storage area. Furthermore, there are a lot of aftermarket Fit parts for tuning (i.e. turbos). Horsepower is great. But do you really need massive hp in a lightweight small car to have the most fun.
darwoodious
Darin Nelson
Dr.Jeff
True Classic
On the subject of chassis strength/rigidity. I believe(?) part of the Honda installation is a complete "subframe" assembly that ties into several key points around the engine bay. That will add a lot of support to the existing chassis. It will likely be much stronger/stiffer than stock.
PaulD
Paul Davock
Thanks Steve. I honestly think any welds you add to a 74 instantly adds more stability it didn't have before
It helps that your welds look terrific.
Steve Hoelscher
True Classic
Thanks Steve. I honestly think any welds you add to a 74 instantly adds more stability it didn't have before
When I was autocrossing my '74 I had problems with the upper rear cross section box being crushed by the top engine mount (dog bone). That piece isn't very thick and it was designed for lateral strength and not to resist the engine's torque being transmitted right into the side at its weakest point. Later models had a fairly thick piece laid over the top of the box section from strut tower to strut tower to add strength for both lateral load and the engine's torque load. I had no issues with my much more powerful '80 model.
Welding up the seams of that lateral box helps but adding structure across the top to tie everything together is a good solution. I did a similar thing on my MR2. I had to cut the rear bulkhead out to clear the throttle bodies and knew that would weaken the whole of the rear structure. So I welded in a length of 1" square tubing right where the box section would be in the '74 X1/9. It worked great.
This is the box section painted to match prior to installation:
And the box tube being welded into place. There was channel that it fit perfectly into from the under side. It was spot welded at regular intervals across the top of the bulkhead and tied directly in the corner pieces of the strut towers. Its now very strong despite the missing bulkhead.
Steve Hoelscher
True Classic
I was going to make this point. That sub frame is pretty strong.
The structure that is added back to the box crossmember is not unsubstantial. Sure, if you were putting a purely lateral load on the box, in complete isolation to the rest of the chassis it might be an issue. But the additional structures of the entire center bulkhead share that load and would likely prevent it from flexing due to the missing section of the box. The upper section of bulkhead would have to have significant deflection for that to happen. The X1/9 chassis is very strong and its strongest point is the bulkhead at the front of the engine bay.
I have contended for decades that if you want a car that's fast in a straight line you really don't want an X1/9. That's not what the car is about. Its the same theory that made the Miata a competent and popular sports car. Its about engaging the driver in the task of driving. The driver makes the car fast, the car doesn't make the driver fast. I have a pickup truck that I tow my racecar with that will out accelerate a NA or NB Miata from 30 to 70 mph, while towing my racecar in its trailer. Seriously.
So you can make anything fast in a straight line if you put enough power in it. The point is; I would have more fun driving the Miata because its light and nimble and rewards the driver when he does it right. The X1/9 is the same thing.
Now certainly, an X1/9 with more power is fun. I have driven a couple of K20 cars and they are very impressive. I would like to have one but I ain't givin' up my SOHC power car to get one.
I think an X1/9 with 150 to 170 rear wheel HP in a smoothly reving modern engine would be a great car. Its still more than 10 lbs/HP but it would be plenty fast. If I were going to do a swap in an X1/9 I would likely use the Toyota 2ZZ engine instead of the K20. Its slightly smaller, lighter and packaged better so it would likely fit a little easier in the X. And I like the engine's power characteristics. It revs smoother than the K20 and makes nearly as much power (190 HP at 8600 RPM).
Dr.Jeff
True Classic
A little off topic, but for some reason I've always thought of 10 lb per HP as a very sweet ratio. Naturally there are a lot of other factors to consider, as Steve explained. But some seriously fun cars I've driven fell into that power:weight ratio. Not that it should be the goal for a X, I'm just saying it is something I have found to be a bit of a milestone. Sort of like breaking the 200 MPH barrier. A neat goal if possible (for a play car), but usually expensive to achieve.
Steve Hoelscher
True Classic
10 to 1 does seem to work out as a very nice power to weight ratio but most modern supercars are well beyond that. Heck, a stock Mustang GT now makes 460 HP and weights 3700 lbs.
My current racecar, a Mk1 Toyota MR2 weights 1686 lbs (ballasted to class minimum weight) makes 165 HP at the wheels (at 9000 rpm). Its a beast. Its also a lot of fun. But the X1/9 racecar (1940 lbs and 90 HP at the wheels) is a completely different experience to drive. Its also a lot of fun, for different reasons.
My current racecar, a Mk1 Toyota MR2 weights 1686 lbs (ballasted to class minimum weight) makes 165 HP at the wheels (at 9000 rpm). Its a beast. Its also a lot of fun. But the X1/9 racecar (1940 lbs and 90 HP at the wheels) is a completely different experience to drive. Its also a lot of fun, for different reasons.
fiatmonkey
Tim Hoover
Love opinions. This is exactly why I post this stuff here. You could do a lot of things differently with these cars and there are lots of options out there. I personally like the k series cuz they have the most options for tuning and bang for the buck. A well tuned k20a2 makes a sweet sound at about 6k rpm and sings all the way to ~9k
fiatmonkey
Tim Hoover
I realized I didn’t answer second question. I have considered rerouting the hard lines under the car but in the end have left them. The boosted x19 will have a slightly different path for the cooling lines upfront since I moved the radiator. But this car new hard lines will go the same route as stock.It’s a thing of beauty
What’s the lower passage (below stock opening) in the center for, revised shifter mechanism? Power /ground cables ? Do you revise the water tube I/O at the rear for the K20, or make the hoses work with stock configuration?
Steve Hoelscher
True Classic
As a good friend of mine says: Baskin-Robins makes 31 flavors because not everybody likes chocolate and vanilla.
There are a number of good candidates for swaps. Obviously the K20/24. I like the idea of a 2ZZ. Heck the MR2's 4AGE would be an easy swap and I think nicely fits the car's character and would have been a very logical progression for Fiat if they had continued development and put a DOHC 1.6 in the X. But then a 4AGE 20v swap would make for a very nice streetable X1/9 with excellent power (180+).
There are a number of good candidates for swaps. Obviously the K20/24. I like the idea of a 2ZZ. Heck the MR2's 4AGE would be an easy swap and I think nicely fits the car's character and would have been a very logical progression for Fiat if they had continued development and put a DOHC 1.6 in the X. But then a 4AGE 20v swap would make for a very nice streetable X1/9 with excellent power (180+).
sub-zeroil
True Classic
If I have added to any motivation for you then my work is done
i took on myself to finish a porsche with efi and all the bla bla in 3 mounts , so it killed me i was try to stay away from this web !
not to cry , but ill push one of the cars out and start on my project hell again ! thanks for the push !