Project MIDTRBO

[Driver_10]

I was planning on using a stock Gen II 76mm crank because I think it'll handle it, and no offset grinding is required. However, I think I'm going with the Falconer 3" (76.2mm) billet crank that my friend Will has (and he's an anal mofo when it comes to engines). He should be able to bring it by tonight so I can look at it. The only thing I dislike about that is that I'll have to use an external crank trigger because there isn't an internal reluctor wheel, but I'll NEVER break that crank, and how cool is it to say "I have a billet crank"?

I take it that he's selling it to you for a reasonable price then. Otherwise, I couldnt justify spending that kind of money on a crank when a 3500 VVT steel crank has a similar stroke. (the only money spent would be to regrind the crankpins for 2.00 rods and to press on a 7x wheel)

I've done the twin-turbo route with my IROC-Z, and it was TIGHT in that engine bay, the Fiero would be a nightmare without getting rid of my trunk entirely which I'm not willing to do. In addition, it adds weight, cost, and complexity (more to go wrong) so I think a single is the way to go with this setup. Equivalent twins wouldn't spool up *that* much quicker anyway I think.
If I eventually go with my longitudinal w/6" stretch idea (with the same 3200) then I'll drop twins down right below the heads. For now that's a pipe-dream, however.

You're a bit too far into your build for me to seriously recomend twins. However, it would be an ideal way to further smooth out the powerband since twins arent as "peak'ish" as single turbo systems tend to be. Honestly though, a single turbo is more efficient for a street driven car.

As I asked in the other thread... Are there solid roller lifters available that'll fit into the Gen III, and will the available roller-cam blank material be able to handle the aggressive ramp rates and extra fatigue?
If I can, at all, get away with using hydraulics reliably, I will, because it will be a royal PITA to get to the valvetrain in this car. I've read that solids won't need much adjusting once they're dialed in (which might still take a few cycles), but everyone recommends that they still be checked regularly because they do move slightly sometimes. Also, I've heard of some possible issues with the knock sensor falsely sensing knock (much like timing gears will do on an injected SBC).

Here's a good article I recently found about valvetrains, well worth the read and it has excellent data. Testing was done with a Ford 5.0 but the same principles apply.
http://www.diamondracing.net/M5LP-060800-SPIN.pdf

I have a set of unused crower solid roller lifters (still need custom push-rods, of course) that I may or may not use for my own project. IF (<operative word)I feel confident that I can get good results using modified hydraulic rollers in a 7500rpm motor, then Ill part with them. (no need to pack-rat car parts, right?)

[ALLTRBO]

Just to chime in I'm running 60# Siemens injectors High impedance on a 7730 without any issues. I recommend them.

So am I. What kind of BPC are you running? I have a smooth openloop idle but can't seem to get the hunt out of closed loop idle. It oscillates up and down with a low BPC reading in the datalog suggesting a rich condition but the wideband doesn't seem to support it. There are several tables that might be involved and I have no idea where to start.

Thanks for the info on the injectors, the more the better. With an 8000 rpm 3.2 I think the pulse widths will have to be very low at idle, so I'd rather just do it right from the get-go with the extra low-z injector driver mod to the '749 so I can run low-z 65#'s.

Joseph, that can definitely be a confusing mess, I had the same issue on my TT IROC-Z. I never did figure it out because there were more pressing issues with the car so I just ran it in open loop, then I sold it.
Are you running $8F currently? I remember reading that you had switched back to it.

I had the exact thinking as you once. The only reason that I gave up on my "de-stroke" 3500 (5.85 rods, .020+ forged pistons and .120 destroked 3500 crank) was simply due to the weight of my car. (That and the fact that I couldnt find anyone in the houston area with the balls to take on the proposed crank grind).

I honestly dont see an issue with your logic other wise. The fiero is light enough to make the need for low-end torqe slightly more irrelevent in your case. Its too bad that you cant build a TT setup to really smooth out that torque band.

The only suggestion that Ill make is getting a set of solid roller lifters. "Hydraulics" simply arent going to be stable at the high rpms that your looking for.

Yeah, I agree about the displacement with the 4thgen, it's noticeably heavier. I wouldn't be destroking this one if I didn't think the low end torque was going to be adequate, I just like the benefits of the short stroke for my application and I really want to see how it does.

I was planning on using a stock Gen II 76mm crank because I think it'll handle it, and no offset grinding is required. However, I think I'm going with the Falconer 3" (76.2mm) billet crank that my friend Will has (and he's an anal mofo when it comes to engines). He should be able to bring it by tonight so I can look at it. The only thing I dislike about that is that I'll have to use an external crank trigger because there isn't an internal reluctor wheel, but I'll NEVER break that crank, and how cool is it to say "I have a billet crank"?

I've been the twin-turbo route with my IROC-Z, and it was TIGHT in that engine bay, the Fiero would be a nightmare without getting rid of my trunk entirely which I'm not willing to do. In addition, it adds weight, cost, and complexity (more to go wrong) so I think a single is the way to go with this setup. Equivalent twins wouldn't spool up *that* much quicker anyway I think.
If I eventually go with my longitudinal w/6" stretch idea (with the same 3200) then I'll drop twins down right below the heads. For now that's a pipe-dream, however.

As I asked in the other thread... Are there solid roller lifters available that'll fit into the Gen III, and will the available roller-cam blank material be able to handle the aggressive ramp rates and extra fatigue?
If I can, at all, get away with using hydraulics reliably, I will, because it will be a royal PITA to get to the valvetrain in this car. I've read that solids won't need much adjusting once they're dialed in (which might still take a few cycles), but everyone recommends that they still be checked regularly because they do move slightly sometimes. Also, I've heard of some possible issues with the knock sensor falsely sensing knock (much like timing gears will do on an injected SBC).

Here's a good article I recently found about valvetrains, well worth the read and it has excellent data. Testing was done with a Ford 5.0 but the same principles apply.

http://www.diamondracing.net/M5LP-060800-SPIN.pdf

[Driver_10]

*Less torque: With equivalent components (top end/cam/etc) a smaller displacement will usually make almost as much power but at a higher rpm. The torque, however, has a higher percentage difference. Look at the stock (late) 3100 vs. 3400 hp and torque for examples. The 3400 has 10 more hp (185 vs 175) but 15-20 more lb/ft. Though the 3400 has 6.9% more displacement (3350cc/3135cc), it has only 5.7% more hp, but 7.7% more torque.
They are, of course, identical other than the bore and slightly bigger TB on the 3400. So to make an even comparison put the 3400 TB on the 3100 and it might gain ~5 hp, bringing the hp advantage of the 3400 to only ~2.8%, but not really changing the peak torque. I've seen several examples of this, stock and modified, some to a more extreme degree...
I want less off boost torque to go easier on the tranny between shifts. It isn't much of a difference, but every bit adds up. Shock loading is what kills trannies, not really horsepower. However, I still want the reasonable off-boost torque of a V6 over a blatty l4 so I wouldn't go that route (been there done that with my Talon... no thanks).

*Rod/Stroke ratio: The 3100/3400 is 1.72:1, the 3500 is 1.79:1, and the "3200" will be 1.96:1
A higher rod/stroke ratio allows more resistance to detonation, which will allow me to run a bit more boost on the same octane (possibly making up for that slight hp drop without retaining that off-boost torque). In addition, the maximum piston speeds are slower.

*Less rotating mass: There will be less shock loading on the tranny between shifts, again. It isn't a lot of a difference, but every bit adds up. It will also use up less hp to turn the crankshaft, mainly at high rpm. Not only because the crankshaft is lighter, but also because the rod journals and the lighter counterweights take away weight from the outside diameter of the rotation, where it counts most.

*Rod availability: Using the 76mm crank and the 3400 pistons (.100 over) will allow me to use 5.85" SBC rods (slightly machined of course) for the perfect piston height vs. quench clearance vs. head gasket thickness, and very stout 5.85" SBC rods are somewhat easy to find, hence easier and cheaper than custom options that will handle ~650 hp.

*Crank strength: This one probably doesn't differ as compared to the forged 3500 crank, but comparing to the 3400 steel crank, there is more overlap between rod journals with the 2.8 crank. Many say that it doesn't matter because no one has ever broken a 3400 crank, but I don't think anyone has ever pushed ~650hp through one either (correct me if I'm wrong).

*RPM capability: All of the above adds up to a rotating assembly that'll probably beg for 7500 rpm with a few valvetrain mods and mild turbo cam upgrade, and intake and head porting (I'm talking about you, Ben. ). Maybe even 8000rpm. My heart skips a few beats at the thought of a jet-like spooling and screaming 7500-8000 rpm 60V6. The 282 doesn't care to shift above 7k from what I hear, but I think that's covered by an aluminum flywheel and lighter rotating assembly, along with my friend Will (aka: "The Dark Side of Will" on RFT and "Will" on PFF) with his awesomz 282 rebuild skillz, heh.

I could also add some panzy-arse reason like the extra gas mileage it could theoretically get, but this car isn't being built for economy, though it'll still be good enough.

I think that about covers it.

I had the exact thinking as you once. The only reason that I gave up on my "de-stroke" 3500 (5.85 rods, .020+ forged pistons and .120 destroked 3500 crank) was simply due to the weight of my car. (That and the fact that I couldnt find anyone in the houston area with the balls to take on the proposed crank grind).

I honestly dont see an issue with your logic other wise. The fiero is light enough to make the need for low-end torqe slightly more irrelevent in your case. Its too bad that you cant build a TT setup to really smooth out that torque band.

The only suggestion that Ill make is getting a set of solid roller lifters. "Hydraulics" simply arent going to be stable at the high rpms that your looking for.

Just to chime in I'm running 60# Siemens injectors High impedance on a 7730 without any issues. I recommend them.

So am I. What kind of BPC are you running? I have a smooth openloop idle but can't seem to get the hunt out of closed loop idle. It oscillates up and down with a low BPC reading in the datalog suggesting a rich condition but the wideband doesn't seem to support it. There are several tables that might be involved and I have no idea where to start.

[Mars]

Just to chime in I'm running 60# Siemens injectors High impedance on a 7730 without any issues. I recommend them.

[ALLTRBO]

Yep, he's definitely a class act. There are no shady dealings with him, he's very polite, and he gets things done right.

Your 'finishing details' are similar to mine of course, and that's part of what would take me forever. I can do all of it, just not any time reasonably soon. It's hard to accept 'defeat', and humbling too. I can sort of console in the fact that I have all of the say as to how the car is being built (while listening to input as well, of course). Some people send in a car and say "give me xxx horsepower". I'm not one of them.

I can post more pictures when I get time, no problem. I the meantime, you can see most of what I have in my PFF thread (linked above).

Thanks.

I just read through this again briefly and realized that I forgot to give credit to who's completing 90% of my build.

Dave and crew at the "Haus of Guru" in Lakewood NJ are building up most of this because I had to give in due to health issues and realized I'd probably never get it done otherwise. He is member "bmwguru" on the Fiero forum, he owns a German car repair shop that he opened up a portion of to do Fiero-only swaps, mostly 3800SC's (he whips them out in no time, very cleanly and reliably!). Mine has been his biggest Fiero project though. He does excellent work at a VERY reasonable rate.
Unbeatable bang/buck, honestly.

I bought the car as a roller with the suspension powdercoated and barely hanging onto the car and without any brakes. With the help of my friend (I should say 'hired help'), I installed the TGP engine onto a 5-speed with a Clutchnet clutch and put it into the car, with the TGP top end still. I figured out that I needed the Gen III top end for my huge turbo's clearance for the place I wanted to mount it, so I pulled the Gen III top end off of a JY engine (two actually). I had ordered a ton of new parts for the car also.
That's when I had to give in and have it picked up by Dave's wife Joey who hauled it up to NJ.
As I explained in the PFF thread, I hate having to give in because I like to do everything myself, but sometimes reality kicks in, so I had to swallow my pride if I wanted this car to be finished.

It's all being built specifically to my design along with the aid of Dave's wisdom so I can only take credit for what's being done, not for doing it. I am going to complete the entire water/air IC system, all tuning, all of the bodywork, more suspension work, and the new 3200 bottom end, though.

That being said, thanks again because it's my design, but Dave and crew are doing the nice work!

I purchased some things from him resently, he's a class act in my opinion, one of the few that still frequent the Fiero forum. I can imagine the struggle of having to let someone else take over for you. Aside from the distance problem with me finishing my swap, I often have a motivation problem when I am home. The little odds and ends add up and can be overwhelming, from odometer rewiring and calibration, to the swap from vacuum operated to electronic cruise control and putting the wires and additional gauges away neatly. I still have to address the A/C, additional relays for the heated O2 sensor and additional accessories (oil cooler fan), water/meth kit, new tubing design for the front mount intercooler to accomodate the reduced ride height for the lowering springs waiting for install, then there's the heavy duty radiator that hasn't been installed yet. It's overwhelming when you're working with limited time. I'm still struggling with the urge to build the forged motor and try to install it next trip, eventhough I haven't completed the reinstall of the engine from the improvements on last visit. On top of that I want to remove the body panels and have them painted. So, I need to sit down and draw up a reasonable schedule as to what it's going to take to get the job done. Put some more pictures up when you get a chance if you're okay with that.

[ALLTRBO]

Thanks.

I just read through this again briefly and realized that I forgot to give credit to who's completing 90% of my build.

Dave and crew at the "Haus of Guru" in Lakewood NJ are building up most of this because I had to give in due to health issues and realized I'd probably never get it done otherwise. He is member "bmwguru" on the Fiero forum, he owns a German car repair shop that he opened up a portion of to do Fiero-only swaps, mostly 3800SC's (he whips them out in no time, very cleanly and reliably!). Mine has been his biggest Fiero project though. He does excellent work at a VERY reasonable rate.
Unbeatable bang/buck, honestly.

I bought the car as a roller with the suspension powdercoated and barely hanging onto the car and without any brakes. With the help of my friend (I should say 'hired help'), I installed the TGP engine onto a 5-speed with a Clutchnet clutch and put it into the car, with the TGP top end still. I figured out that I needed the Gen III top end for my huge turbo's clearance for the place I wanted to mount it, so I pulled the Gen III top end off of a JY engine (two actually). I had ordered a ton of new parts for the car also.
That's when I had to give in and have it picked up by Dave's wife Joey who hauled it up to NJ.
As I explained in the PFF thread, I hate having to give in because I like to do everything myself, but sometimes reality kicks in, so I had to swallow my pride if I wanted this car to be finished.

It's all being built specifically to my design along with the aid of Dave's wisdom so I can only take credit for what's being done, not for doing it. I am going to complete the entire water/air IC system, all tuning, all of the bodywork, more suspension work, and the new 3200 bottom end, though.

That being said, thanks again because it's my design, but Dave and crew are doing the nice work!

[Superdave]

Nice work!

[ALLTRBO]

Post-turbine exhaust, all stainless, almost complete...







When the electric cutout (it's technically no longer a 'cutout') is closed, the exhaust is forced to flow through the 2.5" muffler circuit. When it's open, it goes straight through the 3" pipe. I want the ability to quiet the exhaust down for neighborhood cruising, etc, but at the track/strip or whenever I feel like it, I want it to blow straight through for the least restriction possible (basically, you don't want any restriction after the turbo). The valve is infinitely adjustable so I can set it anywhere in between.

I wanted all of the exhaust to exit the tailpipes, none before, as a typically installed cutout does. The wastegate dump will also be routed back into the downpipe at a 45* angle.

[ALLTRBO]

Yep. '730 is the last three digits of the part number of a GM OBD1 ECU. That's the easy way to tell apart the multitude of them that GM made. The '730 is one of the most common, and it's a speed density and batch fire ECU. I forget all of the applications, but they include 90-92 F-bodies, Some (all?) Berettas and Corsicas, and many other late 80's to early 90's GM cars. Most of them have different code masks to run the various engines.

Batch fire is perfectly fine for most operating conditions because the fuel doesn't sit around for long enough to cause a problem, but when you get into large injectors and large cams on smaller engines, idle tends to be harder to keep smooth. That's where SFI (the real SFI, heh) shines in comparison.

Related; I'm going to run into issues trying to idle 65lb/hr per injector on my 3.2 liter when I get to it, but that'll be helped somewhat by modifying a Syclone/Typhoon ECU ('749) to accept an extra injector driver so I can run 6 peak/hold (low impedance) injectors. I'll probably also have to raise the idle a bit. It's just hard for the mechanical components to restrict that much fuel flow when it isn't needed.

[RedZMonte]

I hereby officially designate SFI as "Single Fire Injection" since I'm using the '730.

Im not familiar with what '730 is.... I assume by "Single fire injection" it is running a batch fire setup where all cyl spray fuel at once? my biddies CRX race car we setup on Accell DFI on a Batch fire and made tons of power, worked well (430HP Turbo on a Single cam D16 1.6L).

S

[ALLTRBO]

It's coming along...

I hereby officially designate SFI as "Single Fire Injection" since I'm using the '730.









The bottom half of the trunk was cut off at the factory ledge and re-welded to make room for the post-turbo exhaust and a rear diffuser.

[ALLTRBO]

Oh, I forgot the title from the other thread mentioning that it's the stock TGP timing cover (normal Gen II), not the Fiero. Sorry for the confusion.
Thanks for the reply.

I know exactly what you mean about the turbo thirdgen. I swapped in a T56, and in cooler weather the car would spin the 275's into its 4th gear.
I planned on going further with the chassis but decided that since I had to give up on either the Fiero or the Camaro, I'd stick with the lighter car with better handling and more traction. :/ It's a no-brainer for a sports car, but a turbo IROC-Z has been my dream car since I was 10 or so, so it was really hard to let it go.
So I had (still have) a no-torque all-traction powerful turbo car, and I had an all-torque no-traction powerful turbo car, and that's why I'm building something with what should be just the right balance (and with better handling).

Oh, and since no one has answered my question in the other forum, can someone help me out here? Here's (roughly) what I posted...

I have a TGP 3.1 shortblock in my Fiero (with 3400/3100 heads/intake) and it has a custom accessory drive done for the swap.
I want to know if all that will bolt directly onto a 3500 block (timing cover/water pump and everything that bolts to that), or if it won't bolt up, what are the reasons? I'd like to know what mods I'll have to make to use it.

There may or may not be a difference in the size of some of the timing cover bolts which shouldn't be difficult to address, definately when installing the Fiero timing cover on a 3.1 block. I've done so many experiments I'm not sure anymore. I did the twin turbo IROC Z28 1986 back in 1995 from the ground up except for the exhaust going from the turbos. Never had more fun driving the Z than I did my slower turbo Fieros, performance cars should be small and agile, not four seaters. The Z was like riding in a very fast closet that was hard to keep pointed straight when the boost came on, Fieros squat and go.