Stock FWD manifolds and exhaust exit location on engine, flange/gasket joint to rear manifold leading to immediate 90 degree turn toward the passenger side, into a shortened Catco universal high flow cat, 180 degree U turn into an unmodified Flowmaster 80 F-body muffler, 2.5" outlets to Z28 style exhaust tips. All bends utilize sections cut from a "donut" - mandrel bend is not tight enough to fit. I had to clearance an area on the cradle, and insulate the hell out of the trunk - check back in the thread for more details.
The DOHC Fiero Swap Project is officially over. I am sucessful in recertifying my 3.4L DOHC powered Fiero GT under California laws and regulations after years of work, patience, and paychecks:
My car now smogs as a 1992 Oldsmobile Cutlass Supreme International, but just looks sexier.
The smog judge was a middle age asian guy, who seemed relatively busy and stuck on fast forward. He was assisted by what looked like a 17 yr old kid who fetched things for him and helped with smaller tasks. The visual inspection, the part that's failed many swappers seemed to take no more than 15 minutes after I pointed out the hidden locations of my AIR pump and Charcoal canister. He seemed disinterested in crawling under the car and taking things apart to ascertain the functions of hard to reach things like the charcoal can, or the PROM chip in the computer my mom and I painstakingly made a GM label for (it's not stock) and took my word on a lot of stuff (I was truthful, more or less).
Next was your basic 2 speed on the dyno smog test. I never saw what number the car blew, but it obviously passed the emissions, and gas cap test. The last part was slightly dicy - the ref pulled out a very expensive looking Snap-On scantool and plugged it into my ECM. Steven's ref was unable to get a link to his ECM, and sure enough this tool would not talk to my ECM, either. I suggested the use of the scantool I borrowed from Steven (it reads everything, fine), and the ref was satisfied after a brief examination to determine that the ECM was connected to all the things it was supposed to. I scanned for codes and showed that it had not engine codes, and he was satisfied with that.
I was worried that something would come up when he said "where do you want to put your BAR label?". It took a minute to sink in, but I PASSED! I finally did it... The gravity of it is still hitting me now, hours later after so many years of work! No matter what happens now, my car is now legal to smog and register like any normal car. **** yeah!
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11:07 PM
Erik Member
Posts: 5625 From: Des Moines, Iowa Registered: Jul 2002
The DOHC Fiero Swap Project is officially over. I am sucessful in recertifying my 3.4L DOHC powered Fiero GT under California laws and regulations after years of work, patience, and paychecks:
My car now smogs as a 1992 Oldsmobile Cutlass Supreme International, but just looks sexier.
The smog judge was a middle age asian guy, who seemed relatively busy and stuck on fast forward. He was assisted by what looked like a 17 yr old kid who fetched things for him and helped with smaller tasks. The visual inspection, the part that's failed many swappers seemed to take no more than 15 minutes after I pointed out the hidden locations of my AIR pump and Charcoal canister. He seemed disinterested in crawling under the car and taking things apart to ascertain the functions of hard to reach things like the charcoal can, or the PROM chip in the computer my mom and I painstakingly made a GM label for (it's not stock) and took my word on a lot of stuff (I was truthful, more or less).
Next was your basic 2 speed on the dyno smog test. I never saw what number the car blew, but it obviously passed the emissions, and gas cap test. The last part was slightly dicy - the ref pulled out a very expensive looking Snap-On scantool and plugged it into my ECM. Steven's ref was unable to get a link to his ECM, and sure enough this tool would not talk to my ECM, either. I suggested the use of the scantool I borrowed from Steven (it reads everything, fine), and the ref was satisfied after a brief examination to determine that the ECM was connected to all the things it was supposed to. I scanned for codes and showed that it had not engine codes, and he was satisfied with that.
I was worried that something would come up when he said "where do you want to put your BAR label?". It took a minute to sink in, but I PASSED! I finally did it... The gravity of it is still hitting me now, hours later after so many years of work! No matter what happens now, my car is now legal to smog and register like any normal car. **** yeah!
Congrats!! ..that sucks though having to go through all of that
The last part was slightly dicy - the ref pulled out a very expensive looking Snap-On scantool and plugged it into my ECM.
We use this snap on scanner at Mikes. Its very high dollar and has a huge digital screen. The reason it most likely doesn't read you car is because your serial data wire is in the wrong place in reference to where that one looks. It wouldn't read my PCM either, but I have since moved the serial wire and would really like to know if it now works.
Congrats on your achievement. I do hope that you go further with your project though.
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04:13 AM
Fierobsessed Member
Posts: 4782 From: Las Vegas, NV Registered: Dec 2001
Same here. I was using Jncomutts autoxray to do scans. I'm pretty sure the snap on will work after changing the serial wire. Unless your saying you also swapped the wire and still couldn't get a reading.
Well, the project is never *really* over, but I've satisfied my mission statement for the whole project, which was to make the car legit!
Now that I'm clear, I intend to shitcan the stocker intake can and water separator, install a modified intake manifold (Steven proved this concept with his dyno run, though maybe I should dyno all stock, just to see what happens before doing the intake. Later on, provided the engine behaves itself and stops making metal particulates in the oil (haven't checked recently), I'm going to install a Holset HX-35 turbo, with ~7 lbs of boost. It's a diesel truck turbo, but it has a really wide efficiency island on the map if you look at it. See the problem is that I'm probably somewhere near 10:1CR with the extra boring, and bumpier pistons and head and block decking, so I can't crank it up much. Shooting for ~300 WHP, and that should do it for me.
Also, on the note of scantools... I was thinking the exact same thing. It was set up for the Olds Cutlass Supreme computer, but my Fiero ALDL is still in Fiero configuration. Oops. I'd be surprised if it didn't remedy the problem. Also the Auto X-Ray probably looks at all the pins the data commonly comes in on, or they're all common, where the Snap-On is more specific.
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08:09 PM
PFF
System Bot
RUNDLC Member
Posts: 802 From: Elk Grove, California Registered: Jul 2005
Blueshift, many congrats on getting her legal! Good thing you had the extra scanner!! I may try and borrow one when I go in about two years. Since I smogged the lambo with the fiero engine it gives me some time to work out any bugs. How long did it take for the process?? from appt to sticker?? My 3.4L seems to be doing fine, I do need to replace the slave right now and then she's ready for an actual road test, I can't wait for that.
From calling in to getting the appointment, it was about a week, I'm sure availability differs depending on the area. Make sure to leave yourself enough time to get everything ready.
When I went in, the whole process took less than an hour. I was in at 3:10P and left by 4:00 sharp. I had the advantage of listening to Stevens story about how it went with him, and was able to be prepared for things like the scantool not working, and the like. They're basically going to check to make sure that all of your smog equipment is there and that it at least looks like it's correctly installed, and functional. No matter what, always tell them that the tranny and engine came from the donor vehicle together - that's probably the quickest way to bring your re-cert to a screeching halt... aside from bringing the car to a screeching halt/crash, which I did the night before my first BAR exam appointment (oooopps...). Don't do that either... Have a VIN number from a CALIFORNIA car - I actually submitted an automatic car's VIN and they were cool with it. Go to the junkyard and jack the VIN from a car in the 91-93 range, but do be sure it's a CA car. Be prepared, and bring documents to show.
She's racked up 3500 miles so far, and made her first 200 mile round trip a couple days ago. Aside from melting part of my plastic toolbox (apparently the heat finally soaked through the heatshield after 2 hours of driving), everything is working right! I'll know if there's more metal when I change oil at 5000... but I figure oil pressure would have dropped through the floor by now if it was a terminal problem. Only time will tell.
What I have planned for the near future:
- N/A power improvements: Big plenum/shorter runner intake (very similar Steven Snyders with some minor changes for the sake of experimentation)
- Suspension upgrades: This thing needs a suspension tuneup, badly. I plan on installing a 88' rear cradle with minor geometry tweaks, coilovers with Konis to get the wheelhop under control (it'll wheelhop for 25+ feet from a stop if you drop the hammer). Anybody know about the Held Slalom front suspension? If I get this job, I'm strongly considering it, provided it delivers performance as high as the price. Between that and the 88 cradle, it should make the car into a serious handler. Any information or experience with the Slalom suspension setup would be gratefully appreciated.
- Big brakes: I have 4, 12" slotted Corvette rotors sitting on my bench, already drilled for 5x100 - I need to get calipers and brackets and get a big brake system set up on my car. Believe it or not, the stock 84-87 brakes stop the car not much unlike stock, and will suffice for general around town use, but they will get you killed very fast in any sort of performance use, so they gotta go.
- Turbo: Once everything is all dialed in, I plan on going with a turbo at around 7 lbs of boost. I've got my eye on a Holset HX-35 turbo - yes, that's a diesel truck turbo, but if you look at the map it's a very efficient turbo, not much unlike a GT35R, minus ball bearings. What's a little bit of spool when the damn things are cheap, plentiful, and indestructable?
- Paint, Rims, Tires: My tires are almost gone, and my rims are too after a bad case of curb rash (engine swap + first rain = bad). It's also time for a repaint once I have everything working. I want to retain the stock blue, maybe add a couple of stripes to the car (I said I wouldn't do racing stripes unless I had something more than the stock 2.8 in, which I now do).
As you can see, projects are never completed! They only get closer to completion.
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01:19 AM
Apr 4th, 2008
Rixthetrick Member
Posts: 145 From: Benowa, Gold Coast, QLD, Australia Registered: Mar 2008
Originally posted by Blue Shift: - Suspension upgrades: This thing needs a suspension tuneup, badly. I plan on installing a 88' rear cradle with minor geometry tweaks, coilovers with Konis to get the wheelhop under control (it'll wheelhop for 25+ feet from a stop if you drop the hammer). Anybody know about the Held Slalom front suspension? If I get this job, I'm strongly considering it, provided it delivers performance as high as the price. Between that and the 88 cradle, it should make the car into a serious handler. Any information or experience with the Slalom suspension setup would be gratefully appreciated.
- Big brakes: I have 4, 12" slotted Corvette rotors sitting on my bench, already drilled for 5x100 - I need to get calipers and brackets and get a big brake system set up on my car. Believe it or not, the stock 84-87 brakes stop the car not much unlike stock, and will suffice for general around town use, but they will get you killed very fast in any sort of performance use, so they gotta go.
Hello from Downunder. Please let me know how the 88 cradle swap goes, I live in Australia and it's going to cost me a MINT to do something like that to my 86GT. Especially issues with the rear strut in the tower, with the geometry altered (apparently even the coilover kit isn't going to make it exactly the same geometry as an '88) I am curious on the 88 Corvette rotors how thick are they? I am asking because a set of GT LIberty front rotors are the exact same stud pattern and centre bore as the Fiero 84-87.
Subaru Liberty GT 316mm Dia ; 30mm Thick ; 57mm Height
I already know they bolt onto a turned front hub to be used with the longer wheel studs... I have seen them here in Australia on a Fiero with Willwoods... Wheelhop? Do you have a rear anti-sway bar? I guess yours puts out a lot more HP than my 2.8
Yeah I've been researching the 88 swap. Apparently the cradle itself will bolt right in without a problem, but as you said the struts will be at the wrong angle, leading to incorrect camber that's beyond the range of adjustment. I guess the fix is either to carefully cut and weld to relocate where the struts sit (which will require coilovers - the large stock style springs will hit in the new location), or to buy Held's 88 cradle adaptor kit, which can be had in conjunction with the coilover kit as well: http://www.heldmotorsports....ero/CoilOverKit.htm. I can't say that it doesn't sound tempting to just buy fabricated parts - I'm tired of cutting and welding! As for the Corvette rotors, let me go outside and check... They're measuring about .795, so .800" or 20mm? That's interesting, what's the diameter on those Liberty GT rotors? As for the wheel hop, I think that the springs I have in there are insufficient for the bigger, heavier engine. And I'm positive that the Monroe Sensatrac struts don't have enough dampening to do the job. When the money comes in, I plan on getting coilovers, Konis, and be done with it. No AR bar in the back.
Other than that, I've been bored and the gearhead bug has bitten me again. I've been working on replacing my current stock 92' intake, stock Fiero air pot, and stock water separator/silencer for something that flows better. Steven had good results on the dyno with a chopped down 91-95 intake, with a large tube plenum welded in place. I went junkyarding with my dad to pull a 91-95 upper intake manifold/plenum from a DOHC, but for the first time in a long while, didn't find anything. That's when I realized that I have a 1996 DOHC intake manifold. Why not start off by using the 96' manifold? The runners are already shorter, and much larger than the early manifold. The stock plenum is much larger, and there are nice flared ends on all of the runners where they meet the plenum. I went outside and took some measurements and did some calculations:
Ok. I went and took some (approximate) measurements of the 96+ intake system:
1996 runner area, as measured at the gasket flange on the LIM: 2.02" x 1.32" = ~2.664"^2. Might be closer to 2.5"^2 accounting for rounded corners. In comparison the 92 LIM runners measures 1.1"x2.0" at the UIM/LIM gasket flange surface.
1996 runner length: UIM = ~10" from plenum to gasket flange, LIM =~3.5". I tried to do this with a tape measure so it's not the most accurate measurement ever. The whole thing comes out to about 13.5" or 34.29cm long to to cylinder head. This does NOT include the port up to the valves.
Since my knuckles bleed profusely from scraping t3h ground whenever I operate my TI83 calculator (and I failed precalculus), I looked up a couple simple formulas to get an idea of where I'm starting at and what I'm looking at, I tried out a couple formulae from this site: http://www.team-integra.net...le.asp?ArticleID=471 ---------------------------------------- 1.) David Vizards Formula The general rule is that you should begin with a runner length of 17.8 cm for a 10,000 rpm peak torque location, from the intake opening to the plenum chamber. You add 4.3 cm to the runner length for every 1000 rpm that you want the peak torque to occur before the 10,000 rpm.
For 6000 RPM, Length = 35cm For 5000 RPM, Length = 39.3cm ---------------------------------------- 2.) Another Formula to Calculate Runner Length for a Specific Peak Torque RPM: from Steve Magnante at Hot Rod magazine N x L = 84,000 where N represents the desired engine rpm for peak torque and L is the length in inches from the opening of the runner tube to the valve head.
For 6000 RPM, L = 14.0" or 35.56 centimeters to the valve head For 5000 RPM, L = 16.8" or 42.672 centimeters to the valve head
Hmm... it looks like the 96 intake was designed to produce a peak torque figure somewhere between 5000 and 6000 RPM already, depending on how much the intake port measured up, and if these calculations are anywhere even remotely close. It also looks like there are decently nice flares already designed into the runners, and a large, unobstructed plenum already designed in. It's going to depend a lot on valve timing to take any advantage of the runners resonant properties - if they aren't open at the right time, then all is for naught. Ah, the joy of pulse tuning theory.
I also had the idea to use a late model Northstar throttle body - they're nice and big, and use the same TPS and IAC. It looks like one rule of thumb suggests that the throttle body bore be 25% less than the diameter of the plenum for optimum flow while working the plenum as a resonator, I'll need to figure out the stock TB and see if the N* is way overkill or not.
But yeah. I'm going to try to take somewhat of a scientific approach and see if I can produce results. More will happen as I order parts and get to work. I have yet to determine if cutting down a 96 intake from its original form is even a wise idea to obtain the torque peak where I want it, and increased top end power. We shall see.
