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| 1988 LFX Build Lessons Learned/How to (Page 2/11) |
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msweldon
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APR 23, 01:13 PM
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| quote | Originally posted by Dennis LaGrua:
Great thread, and excellent job. I will agree that this swap makes sense being lighter, provides more horsepower, and uses more modern technology. Using regular gas with 11.6:1 C/R is a very good feature. The only negative that I see with the LFX is that the engine is big and will not fit in the Fiero engine compartment without cutting out the trunk. It is also a drive by wire engine and has some unique features like its requirement for Dexos oil. This swap has been around for a while being done in other vehicles and its nice to see it being put in a Fiero.
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The engine is quite compact, for what it is...... and much smaller than the LQ1 DOHC, specifically the heads and the cam drive system, to the point where the decklid hinges do not have to be cut with room to move it side to side based on the axle solution chosen. Definitely no trunk cutting necessary.... maybe if you went with the LF3/LF4 turbo OE turbo layout but definitely not with the LFX. The heads are miniscule as compared to the LQ1 heads, then again aren't most all heads small compared to the LQ1. Mine is offset 2" from the stock layout and no decklid hinge box cutting necessary. IMHO, the only limiting factor of this swap is the lack of prevalence of the Saab Aero F40 6 speed transmission with its GM Global bolt pattern and it's stump pulling 1st gear. (which can be addressed but at a cost)
Regarding the Dexos.... from what I've read, GM did a large amount of research and development regarding the Dexos specification. Dexos specifies a particular set of characteristics that these DI, VVT engines require to maintain their expected level of performance and reduce warranty claims, i.e. reliability. Small price to pay for a 3.6L V6 with 300hp+ These are "not" the 2.8-3.4 60 degree or 3800 V6s from before...
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RandomTask
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APR 25, 04:44 PM
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So I realized I'm out of stainless wire so I can't weld stuff up until that get's in. Oops.
That stated, started taking things apart and moving things where I wanted them to be. Pulled the radiator and cleaned everything up; pre-cleaning:
Pulled the passenger coolant tube. I knew I'd need to fix this going in so I already have a replacement section to weld in. I sectioned this piece to see how bad it actually was. . . It was bad. . .
And putting the new radiator in place. I'm super tempted to replace the AC condenser at this point but don't feel like spending the $300 on it yet so I'm going to hold off. Once the SS mig wire comes in, I'll go ahead with finishing cutting the coolant tubes then welding them back into the orientation I need.
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Will
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APR 26, 08:43 AM
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| quote | Originally posted by RandomTask:
So I realized I'm out of stainless wire so I can't weld stuff up until that get's in. Oops.
Pulled the passenger coolant tube. I knew I'd need to fix this going in so I already have a replacement section to weld in. I sectioned this piece to see how bad it actually was. . . It was bad. . .
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-Chop it right at the buckle
-Form each side of the cut round
-Butt weld back together
-????
-Profit!
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msweldon
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APR 27, 10:38 PM
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| quote | Originally posted by Will:
-Chop it right at the buckle
-Form each side of the cut round
-Butt weld back together
-????
-Profit! |
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Use a tig if you can with those pipes unless you are far better than using a mig than I. I cleaned, solarfluxed, and practiced on a similar size stainless pipe, and these 30+ year old lower grade stainless pipes gave me fits repairing mine. Burned through easily and weld kept going porous on me. I finally got it sealed but the weld is so bad I'm going to cut it and tig on a section instead.
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Will
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APR 28, 08:30 AM
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| quote | Originally posted by msweldon:
Use a tig if you can with those pipes unless you are far better than using a mig than I. I cleaned, solarfluxed, and practiced on a similar size stainless pipe, and these 30+ year old lower grade stainless pipes gave me fits repairing mine. Burned through easily and weld kept going porous on me. I finally got it sealed but the weld is so bad I'm going to cut it and tig on a section instead. |
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I had a really good welder to the repair on my pipes, so I can't comment on how easy or difficult they are to weld. Butt welding thin wall tubing is already a varsity skill.
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RandomTask
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APR 28, 10:49 AM
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| quote | Originally posted by Will:
I had a really good welder to the repair on my pipes, so I can't comment on how easy or difficult they are to weld. Butt welding thin wall tubing is already a varsity skill. |
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While a lot easier on TIG to butt weld, you can do it on a MIG if you pay attention. Obviously, make sure you're using the right filler as well as tri gas (He/Ar/Co2) and make sure everything is nice and clean.
I initially tried using an exhaust expander to try and expand some of the pipe so I can slip the replacement in/over the other but unfortunately, the pipe expander broke trying to do this. I think the material is just too strong to expand
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msweldon
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APR 28, 06:37 PM
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Goto Napa, they have sockets with a tapered face that you can use as a mandrel to shape the pipe, just remember to put a long bolt through the socket to use as a slide hammer to extract the socket.
I copied Steven Snyder's instructions here..
http://steventsnyder.com/re...fiero-coolant-tubes/
Worked really well...
I did use tri mix, 308 filler, and cleaned the tubes inside and out....i probably just stink that much at welding. Lol!!
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RandomTask
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APR 29, 02:48 PM
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So ran into a little bit of a setback. Went to fire up the car; ran fine for about 10 seconds then cut off and couldn't get it fired back up. Realized my fuel pump wasn't on. Checked the relay; it worked but pump wasn't turning on. Checked the fuse and it was blown. Replaced the fuse with the relay manually engaged and you could hear the pump run, dead head to a stop, then saw the fuse pop again. (something about electric motors hitting max current at 0 rpm)
Car has funky throttle response (as in not running right). It would appear that since the pressure is too high, the ECU is trying to compensate and is simply running too short a pulse to deliver any fuel. I just bought a fuel pressure gauge as well a universal regulator so I can set it to 55psi and forget about it. I'll have to plumb that in. Boo.[This message has been edited by RandomTask (edited 04-29-2021).]
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Will
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APR 30, 09:20 AM
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| quote | Originally posted by RandomTask:
So ran into a little bit of a setback. Went to fire up the car; ran fine for about 10 seconds then cut off and couldn't get it fired back up. Realized my fuel pump wasn't on. Checked the relay; it worked but pump wasn't turning on. Checked the fuse and it was blown. Replaced the fuse with the relay manually engaged and you could hear the pump run, dead head to a stop, then saw the fuse pop again. (something about electric motors hitting max current at 0 rpm)
Car has funky throttle response (as in not running right). It would appear that since the pressure is too high, the ECU is trying to compensate and is simply running too short a pulse to deliver any fuel. I just bought a fuel pressure gauge as well a universal regulator so I can set it to 55psi and forget about it. I'll have to plumb that in. Boo.
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Well something's dead-heading the pump, so I would not expect the engine to run correctly. Is your regulator malfunctioning? I had a BMW E30 in which the return line to the tank was clogged solid. I had to replace the tank. That's not a need for tank replacement in a Fiero, but do some checking to see if it's the regulator or not.[This message has been edited by Will (edited 04-30-2021).]
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RandomTask
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APR 30, 01:59 PM
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| quote | Originally posted by Will:
Well something's dead-heading the pump, so I would not expect the engine to run correctly. Is your regulator malfunctioning? I had a BMW E30 in which the return line to the tank was clogged solid. I had to replace the tank. That's not a need for tank replacement in a Fiero, but do some checking to see if it's the regulator or not.
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Currently there is no return and thus, no regulator. The "lift" pump feeds the high pressure pump. I'm installing a regulator on the lift pump circuit. So the fuel pump will feed through a filter, into a regulator. I'll set that regulator to ~55psi. That regulator will have a feed to the high pressure pump and also a return back to the tank. The high pressure pump then feeds the fuel rail and has it's own return system; basically I'm going to make sure there's a constant 55psi to the high pressure pump. I'm utilizing a walboro 255 unit so basically, it's feeding as much as it can so ~100psi, which is no bueno.
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