High Feature V6 Swap

[Shaun41178(2)]

Why do you want yo use the jackshaft? Why not have a longer passenger axle like factory fiero?

[draven]

Why do you want yo use the jackshaft? Why not have a longer passenger axle like factory fiero?

Not taking that off the table but the oil return line, coolant feed lines, and to a lesser extent the front TD04 housing could be impacted by the axle on full jounce. Furthermore, the beefy cobalt SS turbo axles mate right into the F40 and halfshaft and will work with only a small shift of the block on the cradle.

I 'thought' the saab halfshaft carrier would bolt right up without issue as it can to all LFX's but it would have to lose one bolt hole due to the oil return line.

Hindsight is 20/20 and I still may go back to it... but an 3.63 FD F23 with a quad 4 bellhousing with custom block to bellhousing adapters and stock fiero axles might have been a better choice...

[The Dark Side of Will]

Why do you want yo use the jackshaft? Why not have a longer passenger axle like factory fiero?

With the F40, that's actually harder than it is with 282 or F23. GM never made any long axles, only intermediate shaft setups.

Also, as with my Northstar car, sometimes packaging works out better that way. I'd melt inner CV joint boots like it was going out of style if I didn't use the intermediate shaft.

Under the CV joint


Above the axle


Below the axle

[The Dark Side of Will]

This from an XTS Vsport not SRX. I know...confusing.. but the SRX does use the LFX so essentially the same block... but the crank is forged in the XTS LF3 but probably has the same crank bolt circle.

The bolt circle diameter is approx 80mm

In mentioning the SRX and STS, I just mean between the 3.6 and Northstar the part numbers were different.

The Northstar bolt circle is 8x78mm with 8mm bolts. It looks like the 3.6 is a smidge larger. Please measure when you take the flexplate off.
The Northstar crank pilot journal is 1.102" (32mm) while the flexplate pilot bore is 1.108". The 3.6's is considerably larger than that, probably because it has to accommodate a pilot bearing in some applications.

[draven]

This from an XTS Vsport not SRX. I know...confusing.. but the SRX does use the LFX so essentially the same block... but the crank is forged in the XTS LF3 but probably has the same crank bolt circle.

The bolt circle diameter is approx 80mm

In mentioning the SRX and STS, I just mean between the 3.6 and Northstar the part numbers were different.

The Northstar bolt circle is 8x78mm with 8mm bolts. It looks like the 3.6 is a smidge larger. Please measure when you take the flexplate off.
The Northstar crank pilot journal is 1.102" (32mm) while the flexplate pilot bore is 1.108". The 3.6's is considerably larger than that, probably because it has to accommodate a pilot bearing in some applications.

The flexplate/flywheel bolts for the 3.6 crank are M10x1.0 same as the legacy 60deg V6's just with 8 instead of six... I had to use the 3.6 flexplate bolts to temporarily attach and lock the flywheel on the current LQ1 build while installing the crank/pulley bolt.

PIlot bore on the flexplate is 40mm or 1.574"

[draven]

Remote oil filter / cooler adapter so the massive stock coolant based oil cooler can be removed, make room for the cradle, and test fit a GMC acadia engine mount.

[draven]

Ok.. put some more time back into the LF3 swap.

No dice on the rear GMC acadia motor mount/carrier combo.. sits too high for any adaption due to the F40 half shaft sitting a .75" lower than the GM automatics equipped to the 3.6. The front Acadia mount shows promise but the turbo oil return line will require some mount removal.. I'll see how much I have to trim out.

Given the stock output of this engine and potential high end my plan is to hook up 4 mounts to the 88 cradle and utilize the 5th on the front of the engine to attach to either the strut tower housing or up and over the engine to the stock dog bone location and a 6th on the top of the saab F40 that could be attached to the frame rail giving six points of contact. Overkill?

Any pros/cons about running a mechanical water pump at the location of the deleted power steering pump to cycle the A2W intercooler water? Or better just to stay with the OEM or aftermarket PWM'd electric coolant pumps?

Also, the lf3 I received had its PSP, Alt, Starter, and compressor removed. There are two alternators I could use... a 170amp 2.0T and 3.6LFX Alternator and the 220amp version for the twin turbo XTS. I won't be running nearly the electrical systems the XTS has but will still may have an electric coolant pump ~10amps and the MR2 spyder electric power steering 5-20amps . SWAG calculations show that the 170amp alt should be more than adequate for the fiero systems (stock 94amp alternator) plus the EHPS plus the A2W pump with adequate headroom or am I missing something big here?

[ericjon262]

the further away from the axle centerline that your mounts are, the more resistance to radial motion the should provide. having them further apart, may remove the need for the additional mounts, and may as well help with packaging depending on crossmember locations. there are pictures of my passenger side engine mount, and rear trans mount in my build thread here:

viewtopic.php?f=16&t=17757&start=320

I don't have any other pictures handy though. I used sleeves that are sized for truck leaf spring bushings like these:

https://www.barnes4wd.com/DOM-Sleeve-Po ... p_137.html

I haven't driven the car with this setup yet, so I am unsure as to how it will feels.

Edit:

My car is a 3500V6 and F23 5 speed, so the mount design will be different, but the same concept can be used.

[draven]

I don't have any other pictures handy though. I used sleeves that are sized for truck leaf spring bushings like these:

https://www.barnes4wd.com/DOM-Sleeve-Po ... p_137.html

I love the setup these come in but really prefer rubber bushings.... getting older over here..

Looking at these...
https://jksmfg.com/i-9052791-fab-bushin ... -wide.html
https://jksmfg.com/i-10079652-oe-rubber-bushing.html

Cool! Good find!

[draven]

Did some initial vertical sizing up of the LF3/F40 combo last night...



Still a little worried about the clearance the compressor to intercooler lines will have.




and from what it looks like the stock front fiero mount is going to have to go....





The carrier bearing bracket is the Saab 9-3 version with the far left bolt hole lopped off to get the intermediate shaft, axles, links, knuckles, etc.. mounted for cradle placement and to mount either the cannibalized XTS half shaft mount or brace the saab 9-3 mount.


Massive coolant based oil cooler removed off front bank of engine..

[draven]

Ok.. going to need some of you turbo experts to chime in... this is scope creep almost at its worst but I may not have a choice...

Like a dorkus maximus I took the LF3 "Engine" width as my base preliminary measurement for it shoehorning into the Fiero's engine bay.... not the engine width plus the compressor outlet and bypass piping. The LF3 width from valve cover to valve cover including the width of the compressor piping is 5" total too wide for the fiero engine bay. So without some serious alterations to the twin TD04's routing or trunk wall/firewall I don't think the twins will work.

But hey every problem is an opportunity in disguise right?

In lieu of this I'm either going to have to:

1.) Get creative in routing the TD04 compressor outlets down the side of the engine and back up over the heads to the IC. Don't really want to mess around with modifying either the firewall or trunk wall. Unless any of you have any outside of the box ideas.

2.) Dump the twins all together and go with a traditional single remote mount over the trans and split the compressor output into the stock IC.

Favoring the remote mount as it

• frees up considerable space on the sides of the block for AC lines and muffler

• reduce heat against the firewall and trunk wall

• headers will be almost a non issue as the heads only have a single exhaust port

• allows for a more appropriate sized turbo and not the minute twin TD04's that hit full boost by 1100rpm (a little hyperbole, but you get the point)

• allows the utilization of other LFX/CTS LF3 block to cradle stock motor mounts due to the turbos being out of the way

Having said all of this... I need some help from you fellas on sizing a proper turbo for this bugger... proper turbo for me would be a wide fat mid-range torque turbo... not something that hits like a freight train at 4.5K rpm... Gretchen Growl of Camaro5.com pushed his LFX with ZL1 pump and LF3 HPFP to 647 RWHP and 726 lb-ft RWTQ at 20psi +/- 2psi with a pair of small remote mount borg warner turbos... Effectively he had recreated the LF3 with lowering compression to 10.2 and forged rods, etc... I'm not looking to build a quarter mile demon but rather a very streetable track car. Tentative goals are around 550 hp/tq to the wheels which I think is doable with a large margin of safety for this engine.

After calculating lbs/min via VE, Liters, max rpm (6500) I cam up with roughly 27 lbs/min at 3000 rpm and 58 lbs/min at 6500 with a max 18psi or 2.2 PR. With the somewhat conservative ballpark calculation of 9.0-9.5rwhp per lb/min of airflow with this VVT engine should equate to around 600hp. Overlaying this on some of the Garrett compresssor maps the the GTX3076R , GTX3576R look promising or maybe a GTX3582R if I decide to push the engine up to 7000rpm. Using the Borg and Warner Turbo Match Bot some of the S300-SXE or S400-SXE's look pretty good too..

Just need some sanity checks on what I'm doing here and what to watch out for especially with turbine selection, surge at boost onset, and choke point. Honestly for me contemplating these levels of hp/tq in a fiero is a bit humbling... fastest things I've driven is a Gallardo and Ferrari 430.

I'll get some compressor pics up tonight.

[Shaun41178(2)]

Dave mcclung got one of these engines swapped into a fiero with the factory location turbos if I am mistaken. Yes?

If goal is 550 whp then a 3076x will prob be too small on the exhaust side. The exh wheel cant flow what the compressor can so it chokes out. The 3576x is a better pairing. Go with the tial vband stainless exh housing. Its way more compact which you will need the room.

A 2.2 pressure ratio is only like 16 lbs of boost? You mihht need to go larger than a 3576x to hit 550 whp on that amount of boost but that will kill your midrange. A 3582 should flow enough. That will prob start coming on around 3k rpm

[draven]

Shaun,

Dave Mcclung put the Saab 2.8 V6 Turbo or LP1 in his fiero… that's a single turbo mounted over it's F40 transmission with headers and a cross over... not the LF3 were it has it's twins mounted more or less to the block right off of the block or it's integrated headers....

I'll effectively be recreating that setup on the LF3, layout wise, but unfortunately I wont be using any off the shelf GM/Saab LP1 parts as I've talked to enough saab v6 turbo guys thus far and they all ditch the stock cross over and exhaust as they are highly restrictive.

2.2PR comes out to 17.64psi, correct?.... so technically 2.2 to 2.3 PR for 18psi...

Looking stay right around 18-20psi

[Shaun41178(2)]

I am going to have to go through the math but I think your engine is gonna make way more than 550whp on 18 lbs On a single turbo

I think you will be closer to 600-625 whp. It will prob do 550 whp on 14 lbs compressor size making the difference obviously.

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.

So the pipes from the turbos up to the intercooler will hit the firewall area and bottom of decklid?

And the pipes on the trunk side will hit the trunk wall too?

[draven]

I am going to have to go through the math but I think your engine is gonna make way more than 550whp on 18 lbs On a single turbo

I think you will be closer to 600-625 whp. It will prob do 550 whp on 14 lbs compressor size making the difference obviously.

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.

So the pipes from the turbos up to the intercooler will hit the firewall area and bottom of decklid?

And the pipes on the trunk side will hit the trunk wall too?

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.

[Shaun41178(2)]

Yea I assumed the lfx has the 4 bolt integrated runners in the head but wasnt sure about that 2.8 Saab.

Shouldn't be too hard to fab up a flange to bolt to each head and run a crossover.

If you want a strong midrange I would go with like a gtx3576 or a gtx3071. The 3071 will come on quick. But wont hit your target. Those wont meet your goal of 550 whp on your target boost but it will be fun. Those would prob be closer to 450- 500whp maxed and near choke line of the compressor

For more top end a 6466 or even a precision 6766 would pull hard.

For me, the smallest I would go is a x3576 or in the precision line a 5858. Thats for good mid range but might struggle to hit 550whp as the compressor is out of flow at that pr.

For 550whp no less i would get no smaller than a x4088 or a 6466. Either turbo will have you ina good efficiency island on the compressor map with a bit of room to grow.

I like the Borg Warner's but their compressor housings are quite large and would be tougher to package. Thats why I dont recomment using them unless trunk mounting

I worry about a clutch that will hold but I think the trans you are running has a larger bellhousing than the getrag 282 I was running. Which means you can fit a larger clutch. I was running a spec 5 at 530 whp and it had trouble holding at peak tq. The pressure plate was garbage though so that might have played a roll. The pressure plate had like only 1400lbs of clamping force. I had one modified to about 2200 lbs but never used it as I sold the intake and heads before I could install it

[draven]

Thanks for the advice, seriously....Haven't looked at the GT40s yet.. I'll get you the link to the Camaro lfx that was hitting 627hp 700+tq at 20psi on two smallish bothe warners with a torque peak around 2500rpm.

Also looking at the Gen II GTX3582R which might be a good compromise between GTX3576 and GT40...

Have a Clutchnet saab solid billet flywheel, 6 puck sprung clutch, with their stage 4 or 5 pressure plate on order...

"guaranteed" to hold 800hp

[Shaun41178(2)]

Do you plan to keep the stock inlets into the intercooler and just modify the pipe from the turbo to clear with a single turbo?

If so then perhaps using factory turbos with just modified pipes would be easier to fab? Dont know just brainstorming

[draven]

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 Dark Side of Will]

This from an XTS Vsport not SRX. I know...confusing.. but the SRX does use the LFX so essentially the same block... but the crank is forged in the XTS LF3 but probably has the same crank bolt circle.

The bolt circle diameter is approx 80mm

In mentioning the SRX and STS, I just mean between the 3.6 and Northstar the part numbers were different.

The Northstar bolt circle is 8x78mm with 8mm bolts. It looks like the 3.6 is a smidge larger. Please measure when you take the flexplate off.
The Northstar crank pilot journal is 1.102" (32mm) while the flexplate pilot bore is 1.108". The 3.6's is considerably larger than that, probably because it has to accommodate a pilot bearing in some applications.

The flexplate/flywheel bolts for the 3.6 crank are M10x1.0 same as the legacy 60deg V6's just with 8 instead of six... I had to use the 3.6 flexplate bolts to temporarily attach and lock the flywheel on the current LQ1 build while installing the crank/pulley bolt.

PIlot bore on the flexplate is 40mm or 1.574"

Thanks! Were you able to take an actual measurement of the bolt circle on the flexplate?