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| Different 3.4l piston/head compatibility (Page 5/7) |
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1985 Fiero GT
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AUG 13, 07:18 AM
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| quote | Originally posted by 82-T/A [At Work]:
What system are you running in order to get SFI? You're not using the Microsquirt are you? I thought that didn't support SFI?
My understanding is that throttle response and around-town driving is greatly improved by SFI over MPFI. I've driven both, just not in the same car, so it's speculative. |
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He runs a megasquirt, those have 8 fuel outputs, microsquirt has 2
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pmbrunelle
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AUG 13, 07:23 PM
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| quote | Originally posted by 1985 Fiero GT:
Ok, explain the checking clearances thing?
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Hydrodynamic bearings in an engine work best when there is a specific gap (which is oil-filled) between the shaft and bearing. Verifying the clearances is standard practice when rebuilding an engine, search online for more about this topic.
| quote | Originally posted by 1985 Fiero GT:
What kind of duty cycle were the accel 30lb injectors running?
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94% duty cycle was observed at 175 kPa MAP:
https://www.fiero.nl/forum/...L/142133-5.html#p198
| quote | Originally posted by 1985 Fiero GT:
Yeah, the slave will be fairly close, if not protruding between the 2 halves a little bit, I have a few inches between it and the decklid spring (which is more to the side) to get it fine tuned.
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The slave will be baked by the turbine's heat if nestled between both halves.
It will be difficult to access the slave cylinder's bleed screw.
Furthermore, there are oil (and optionally water) connections which are made to the CHRA; the slave in that position will interfere with the plumbing.
I think you should try to push the turbo ahead of the slave cylinder, if it can fit.
Idea: a K03/K04 family turbo for VW type stuff may fit well for your proposed turbo placement.
Example:
https://www.ebay.ca/itm/363518942336
The turbine housing exits mostly downwards, and the compressor discharge has an "L" which allows it to step below the decklid spring. I think that it could be mounted pretty high up.
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BillS
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AUG 13, 07:56 PM
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One of the limitations on a Fiero engine of whatever size is the difficulty in installing an intercooler. Without one, around 10 psi is the highest you can go without risking big bang consequences. I ran one th put out around 300 bhp with that much boost and it s dead reliable. I used a 3.1 longer stroke crank. I don't have the experience with the 3400 engines to suggest a maximum using one of them.
I run a 3.4 engine in a front engined car I have and it puts out 190-200 bhp naturally aspirated, but getting it to breath well enough requires a bunch of head work, a lot more cam, the F body upper plenum, and a specially enlarged throttle body.
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1985 Fiero GT
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AUG 13, 07:56 PM
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| quote | Originally posted by pmbrunelle:
The slave will be baked by the turbine's heat if nestled between both halves.
It will be difficult to access the slave cylinder's bleed screw.
Furthermore, there are oil (and optionally water) connections which are made to the CHRA; the slave in that position will interfere with the plumbing.
I think you should try to push the turbo ahead of the slave cylinder, if it can fit.
Idea: a K03/K04 family turbo for VW type stuff may fit well for your proposed turbo placement.
Example:
https://www.ebay.ca/itm/363518942336
The turbine housing exits mostly downwards, and the compressor discharge has an "L" which allows it to step below the decklid spring. I think that it could be mounted pretty high up. |
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That was just a proof of concept cad job, lots of tolerances there, the turbo is about an inch less in diameter than the cutout, and the exhaust side seems to be smaller than the compressor, furthermore, it's just sitting down in there, I can raise it several inches, the hinge isn't the limiting factor, the decklid vent is, to the point that the slave would be in the middle, but below the turbo, I'll install heat shielding of course, as much as possible! but I'll have to see how much space I actually have with the real turbo. Also the higher it is, the more it can go to the left. You can maybe see better here
I'm not to worried about accessing the slave for bleeding, and if the oil connections go straight up and down, they won't interfere,
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pmbrunelle
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AUG 13, 09:30 PM
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1985 Fiero GT
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AUG 14, 12:22 AM
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Yes, I know of those, the f40 has a hydraulic throw out bearing right? I was thinking along the line of figuring out that, when my 4 speed needs synchros or replacement/rebuild, or I break something on it haha.
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1985 Fiero GT
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AUG 14, 12:23 AM
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| quote | Originally posted by BillS:
One of the limitations on a Fiero engine of whatever size is the difficulty in installing an intercooler. Without one, around 10 psi is the highest you can go without risking big bang consequences. I ran one th put out around 300 bhp with that much boost and it s dead reliable. I used a 3.1 longer stroke crank. I don't have the experience with the 3400 engines to suggest a maximum using one of them.
I run a 3.4 engine in a front engined car I have and it puts out 190-200 bhp naturally aspirated, but getting it to breath well enough requires a bunch of head work, a lot more cam, the F body upper plenum, and a specially enlarged throttle body.
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Yeah this engine setup will have pretty low compression, and pmbrunelle has something very similar that runs well at 15psi, no intercooler, no water injection, etc. and had had it a good bit higher with the water injection
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pmbrunelle
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AUG 14, 07:12 AM
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| quote | Originally posted by 1985 Fiero GT:
and had had it a good bit higher with the water injection |
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Nope, not yet, but that's the plan.
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1985 Fiero GT
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AUG 14, 07:14 AM
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| quote | Originally posted by pmbrunelle:
Nope, not yet, but that's the plan. |
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Oh ok, so like 25 pounds without water injection, wow haha
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pmbrunelle
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AUG 14, 07:52 AM
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There is no plan exactly, besides going up in ~10 kPa steps (spending some amount of time at each step, weeks?), and then stopping when it is no longer feasible to continue increasing manifold pressure. [This message has been edited by pmbrunelle (edited 08-14-2024).]
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