Real Fiero Tech

Shaun41178(2) wrote: ↑Sat Feb 09, 2019 5:17 pm So the Saab 2.8 heads are the same as the lf3 and lfx as far as bolt pattern and spacing on the exhaust head outlet? Meaning the Saab 2.8 parts will bolt up?.

They may be restrictive but it gives you a starting point.

That would work with an LLT, but not an LFX. In fact and aftermarket Saab manifold/crossover pipe setup (if there is such a thing) would be pretty nice on an LLT in a Fiero.

draven wrote: ↑Sat Feb 09, 2019 9:50 pm
No.. the Saab LP1 heads are NOT the same as the LF3 especially exhaust ports... the Saab LP1 has the traditional 3 exhaust ports per head where as the LF3 has integrated headers and the single outlet just like the LFX, see below:



Yes, the compressor to IC and bypass to IC pipes up from the turbos over the valve covers would impact the front firewall and trunk wall too... the rest of the turbo assemblies would fit unfortunately right where the fiero bay is at it's narrowest is where the LF3 with it's added plumbing around the sides of the heads is at its widest.

Is that a CD009 trans?

draven wrote: ↑Mon Feb 11, 2019 12:10 am Yes.. looking at modifying the intercooler pipes to clear the fiero bay walls and direct them toward the rear of the engine and merge into one pipe fed from a single.... Not going to be easy as the intercooler inlet is a very odd shape 3.5" x 1 3/8" radiused rectangle. The oem inlet manifold is cast aluminum with some sort of SS resonator brazed onto the aluminum and carefully spot tig'd in 4 locations and another SS pipe swaged onto the end of the resonator... furthermore, one of them is angled in the wrong direction so looking at the CTS inlet IC manifolds to see if I can work with them..

I've sat and stared and stared at the layout of the twins to see if I could make it work... it's possible and I could probably make it work with some less than ideal and convoluted plumbing... as it would be both the compressor outlet pipes and the bypass's (or go with two BOV's) as well. I had halfway planned on going single eventually this just forces me to play my hand earlier and go with a tried and trued fiero/turbo layout. My next concern with a well sized single is if the IC can keep up.

Time to get busy with swapping out the Turbo Cobalt axle stubs and fabbing motor and transmission mounts regardless...

The turbos clear the firewall and trunk wall, but the plumbing doesn't?
"The automotive problem is fundamentally one of packaging" -Gordon Murray.

Does the intercooler block sit on top of the intake manifold?

The Dark Side of Will wrote: ↑Mon Feb 11, 2019 12:36 pm The turbos clear the firewall and trunk wall, but the plumbing doesn't?
"The automotive problem is fundamentally one of packaging" -Gordon Murray.

Does the intercooler block sit on top of the intake manifold?

Hahaha so true... I thought about that quote when I did the measurement and realized the predicament.. essentially the LLT/LFX/LF3 etc.. is only slightly smaller than the LQ1. From edge of valve cover to valve cover they virtually the same +/- .5", which leaves only enough room for minimal engine movement between the fiero firewall and trunk wall where it is at it's narrowest.

Yes the intercooler sits atop the lower intake manifold.

The Dark Side of Will wrote: ↑Mon Feb 11, 2019 12:32 pm Thanks! Were you able to take an actual measurement of the bolt circle on the flexplate?

I'll get that for you tonight...

Here's what the Saab aftermarket has come up with:

https://sites.google.com/site/cbmotorwo ... -turbo-kit

https://sites.google.com/site/cbmotorwo ... -manifolds

Some of their parts may be adaptable to single turbo placement in a Fiero on an LFX with minimal effort, or could save you some fab time in building your own.

The Dark Side of Will wrote: ↑Mon Feb 11, 2019 12:34 pm
Is that a CD009 trans?

Duh, that would be an AY6, wouldn't it?

The Dark Side of Will wrote: ↑Tue Feb 12, 2019 12:30 pm Here's what the Saab aftermarket has come up with:

https://sites.google.com/site/cbmotorwo ... -turbo-kit

https://sites.google.com/site/cbmotorwo ... -manifolds

Some of their parts may be adaptable to single turbo placement in a Fiero on an LFX with minimal effort, or could save you some fab time in building your own.

hahahaha! I've already swapped a couple of emails with him regarding him building just the cross overs for me and his large chamber downpipe..

waiting on his response at the moment if he's willing to take my money or not.. going through the motions to get him to understand the LF3 does "not" have typical exhaust ports and I'll be fabbing the header portion...

Apparently he doesn't want my money.... not a peep in just under a week...


Another minor setback and interesting tidbit... the LFX exhaust manifold bolt pattern is "not" the same as the LF3... at a quick eyeball they look the same however the four mounting bolts do not line up... ordered a set of LFX flanges from CBM motorsports to get a jump on the exhaust fab and they most definitely do not line up.... just one more architectural difference between the two engines....

draven wrote: ↑Fri Feb 15, 2019 4:17 pm Another minor setback and interesting tidbit... the LFX exhaust manifold bolt pattern is "not" the same as the LF3... at a quick eyeball they look the same however the four mounting bolts do not line up... ordered a set of LFX flanges from CBM motorsports to get a jump on the exhaust fab and they most definitely do not line up.... just one more architectural difference between the two engines....

wow, of all the dumb things I've seen GM do... that doesn't make any sense at all to have them that similar, but not the same.

ericjon262 wrote: ↑Sat Feb 16, 2019 4:49 pm

draven wrote: ↑Fri Feb 15, 2019 4:17 pm Another minor setback and interesting tidbit... the LFX exhaust manifold bolt pattern is "not" the same as the LF3... at a quick eyeball they look the same however the four mounting bolts do not line up... ordered a set of LFX flanges from CBM motorsports to get a jump on the exhaust fab and they most definitely do not line up.... just one more architectural difference between the two engines....

wow, of all the dumb things I've seen GM do... that doesn't make any sense at all to have them that similar, but not the same.

Perfectly understandable if the LFX was designed before they decided to build a turbo version. They designed a flange that would work with a naturally aspirated exhaust, then had to change the pattern in order to package it around the turbine housing of the direct mount turbos. Oops. They probably did not update the LFX to use the same pattern as changing ongoing production incurs costs. Changing the flange would change the part number of the close-coupled catalyst on the naturally aspirated engine. I @$$ume that would not trigger an emissions recertification if the flange is the only thing that changed, but I'm not an industry insider.

Do the LFX/LF3/LF4 and LGX use the same pattern for that side of the head casting? If so, does the LGX now use the same pattern as the LF3/LF4?

Ok.. just some minor updates.

First... here is the LFX flange on the LF3 head.. the top two bolts align but as you can see.. the lowers do not align and the port itself is misaligned...

Finally finished up a leveling and mounting system for the block and cradle that's also mobile around the garage...



It's a harbor freight furniture dolley with 4 added castors under the center section made up of two additional 1x12's... took some metric threaded rod into several of the oil pan bolt holes with some couplers and threaded rod feet to stand the engine up for leveling...



The oil pan's oil pan drain bolt, the lowest part of the engine is .5" above the bottom of the cradle...



Temp suspension links attached and brought to parallel and aligned with output shaft holes of F40 with lateral links at level resting ride height. As you can see I'll have about a 5deg slope down from the F40 to the hubs... no problems there...



...and that's about as low as I can comfortably get the LF3/F40 combo...



Next up was centering the engine/tranny onto the cradle laterally and broke out the cobalt LNF axles to attach the fiero axle stubs and center everything up...The bad news is that any rumors of the 08-12' Turbo Cobalt beefy axles being plug and play with the fiero axle stubs is bollocks.....

The fiero star in it's outboard joint has no chance of mating up to the Cobalt LNF Turbo axle shaft... 1.25" vs 1.75" diameter.... which does give plenty of meat to have the ends of the cobalt axles resplined to that of the Fiero / Cobalt LSJ. Going to call TheDriveShaftShop tomorrow and see if they can take care of that.. This will effectively, from what I've researched, turn the LNF axles into the same ones sold with the GM performance parts Cobalt Wheel Hop Kit they came out with around 2008/2009 for the LSJ Supercharged Cobalts, LNF axles resplined with the LSJ axles stubs.

lastly a pic of the IC inlet I'm going to have to cut up / mangle / recreate to get the air flow running horizontal across the top of the heads and 90deg turn into the IC on both sides...



This side is perhaps the more usable as the manifold portion is pointing more or less in the correct direction, back towards the front of the engine. If I can decouple the resonator "can-like" thing off of the cast manifold... I might have something to work with brazing or tig'ing on a pipe elbow in the proper direction.

Beyond that I might have to slice off the manifold flange and use it, or recreate one in mild or stainless to attach a rectangular elbow to round transition.... the opening is a very odd shape and size... rectangular opening with radiused corners measuring 3 1/2" by 1 3/8"

hard to tell, is the pic of the intercooler elbow from the front or rear of the engine?

draven wrote: ↑Sun Feb 17, 2019 11:32 pm
Next up was centering the engine/tranny onto the cradle laterally and broke out the cobalt LNF axles to attach the fiero axle stubs and center everything up...The bad news is that any rumors of the 08-12' Turbo Cobalt beefy axles being plug and play with the fiero axle stubs is bollocks.....

The fiero star in it's outboard joint has no chance of mating up to the Cobalt LNF Turbo axle shaft... 1.25" vs 1.75" diameter.... which does give plenty of meat to have the ends of the cobalt axles resplined to that of the Fiero / Cobalt LSJ. Going to call TheDriveShaftShop tomorrow and see if they can take care of that.. This will effectively, from what I've researched, turn the LNF axles into the same ones sold with the GM performance parts Cobalt Wheel Hop Kit they came out with around 2008/2009 for the LSJ Supercharged Cobalts, LNF axles resplined with the LSJ axles stubs.

Isn't it supposed to be the LNF or G6 star in the Fiero outer housing?

ericjon262 wrote: ↑Mon Feb 18, 2019 3:07 am hard to tell, is the pic of the intercooler elbow from the front or rear of the engine?

The pic is of the right side of the engine with the transmission to the left and behind

The Dark Side of Will wrote: ↑Mon Feb 18, 2019 5:40 am
Isn't it supposed to be the LNF or G6 star in the Fiero outer housing?

Omgosh! Duh...good point...thats what I get for disassembly of cv joints on 2hrs sleep and coaching basketball all day

Trying to fit the Cobalt turbo cage/balls/star into the fiero housing tonight...

On another note... I've been redoing my math for sizing the right compressor... what would be an accurate VE number for the GM 3.6 VVT engines... I would assume mid to high 90's, .94-.97. for a well tuned DOHC engine... However I was talking to an exhaust vendor about some custom flanges and he would put the VE for that engine at 1.15....really?

I haven't tried it on actual compressor sizing, but for naturally aspirated engines I peg the BMW S54 at 100% VE owing to its chart topping 82 ftlbs/liter specific torque. Scaling an engine's specific torque against 82 ftlbs/liter gives as good a guess at VE as any.

Alternatively, log the MAF reading and then back calculate the volume of that mass from air density using barometric pressure, ambient temp and relative humidity.

Ok... more axle woes...

1.) The cobalt star/cage/balls will not fit into the fiero outboard axle stub housing... no way the cobalt is going balls deep in the fiero... the cobalt cage is slightly larger and the balls are a few millimeters larger in diameter.

2.) Here's the 'real' goocher..... after number one above was fully realized I took some measurements on the cobalt vs fiero axle stub ends to make sure the cobalt axle can be resplined.... The fiero splined end is 26.5mm.. the cobalt splined is several mm thicker but is only half as far down the shaft as the fiero splining... behind the cobalt splining, further down the shaft where the fiero splining would be cut.. the cobalt axle necks down to 25.5mm so the end of the cobal axle cannot be splined to that of the fiero..... what a waste of some seriously stout axles......

The cobalt turbo axles 'can' be obtained to fit the fiero if one were to order the GMPP Cobalt Wheel Hop kit but that's $800... might as well get the LSJ stage 2 axles from the driveshaftshop for that amount of coin...

The cobalt parts are all in the lower part of each image...











Looking at either G6 axles by shortening the DS axle by 2" like Joseph Upson and another DS axle for the passenger side to go into the female saab halfshaft but might have to go with the G6 half shaft thereby possibly negating the saab carrier bracket...

Saab 9-3 or 9-5 axles and respline the end for the fiero…

Or go with Dutch Axle out of Idaho and just have them turn two axles like the Cobalt turbo axles with the fiero outboard splines....