Vortech boosted '70 Bonneville convertible
 

A bunch of years back, I fuel injected my 70 Bonneville and swapped in a 4L80E. I've been tweaking the combination and getting it dialed in over the past few seasons, and am finally ready to make another big change.

To that end, I ordered up a Vortech V7 YSi and all of the needed brackets and hardware from Mark at Luhn Performance. I spent last weekend starting the mock-up, and thus far it all fits great! I can't say enough good things about the work that Luhn does.

One of my tasks will be to address the oil return on the blower. I'm leaning heavily towards reworking the passenger side of the timing cover to keep the return plumbing short and clean. Has anyone else here used this approach and would like to comment on it, or share pics of their work?

Anyone have any other approaches they have used and are willing to suggest?

I've attached a few pics of where things stand today. I'll add more as I make progress over the coming weeks.

-Scott

Way cool! Do you have boost level in mind? Or are you gonna find the limit as you go? Keep us updated.

I think a lot of people just drill and tap the timing cover for an AN fitting for the oil drain back.

Really cool project, keep the updates coming!

Many years ago I added a turbo oil drain to the passenger side of the timing cover and redirected the lower rad hose as well to clear it.

Drilling and tapping would probably be simpler.

My plan is to keep the boost levels modest to start - I'm thinking in the 7-8 PSI range initially. From there I'll assess the fuel system, get the boost regions of the
spark and fuel tables dialed in, and just generally see how it drives.

For the oil return, I'm envisioning something like what firechicken shows, except keep the lower radiator hose as-is, and have the oil return come in at an angle. I'm still noodling over how I want to do that. Tapping the side of the timing cover and adapting to an AN fitting is where I'm leaning at the moment using something like this:

https://www.jegs.com/i/JEGS+Performa...SABEgKnU_D_BwE

-Scott

Just remember the oil drain line/hose must ALWAYS be GOING DOWNWARD.

No "U"s in the drain line.

Tom V.

My experience with Jeg's AN stuff- use a name brand. I bought a bunch of fittings from them and ended up replacing all of them with Earl's piece.
The fit and finish was too poor for me to trust the parts. When I mocked up the Earl's, things just glided together smoothly... kinda like using generic carb studs vs. ARP.

100% agreed on the line routing Tom - care will be taken to ensure that it is a continuous slope downward from the blower oil drain to the side of the timing cover.

I would be interested in hearing thoughts on the sizing of this line. At the moment, I have the parts to do this in both 3/8" stainless tube, as well as 1/2". I'm leaning towards the 3/8" just for ease of routing and bending.

Just a thought for you to consider.

The oil/foam coming out of the Vortech Supercharger can, at times, restrict oil from FROM the supercharger with too small of a return line diameter.

The bubbles created by the oil and gears inside the supercharger drive unit will almost always break and the oil will flow with the larger diameter return line.

When I did Belt driven Vortech and Paxton supercharger testing at my job, we always ran the larger rubber hose vs the smaller 3/8" hose because of the wall friction.

Now if you were running a aluminum or steel tube the walls are much smoother and the bubbles ability to block the drain of oil is greatly reduced. We ran the minimum of rubber hose at the two locations, out of the supercharger nipple and into the oil pan nipple.

Just something to think about.

Some "self contained oil" superchargers can get very hot in the oil/gear case.

Tom V.

I wouldn't run anything smaller the a 10 line ..

I'm long overdue for an update, but its summer here in New England, so I'm out
cruising more than wrenching!<g>

One of the issues I encountered in my install that seems to be unique to the
fullsize cars is an interference with the front crossmember. I've attached some
pics to show exactly where the 8.6" diameter crank pulley interferes, and the
cut that I made to eliminate the interference.

It looks closer than it really is in the pics. The belt fits nicely, and there's no less
than 5/16" clearance on all sides.

In addition to getting the front crossmember clearanced, I also had some time
to test-fit the boost-side plumbing. The setup is going to be non-intercooled
for now while I get things sorted.

I'm also going to heed Tom and Charlie's advice to go big on the oil return. The
weld-in -10AN fitting will be here Friday, and I'll get that TIG'd into the side of
a spare timing cover.

The long pole in the project is now the supercharger mounting bracket front
plate. I'm waiting on that from Mark before I can get the rest of the belt drive
hardware fit-checked.

I'm long overdue for an update on this. I finally got the reworked timing cover
back from the welder, and I'm really happy with the results. A -10AN fitting
was added to the side of a spare timing cover, and a custom line was made
to connect the bottom oil drain on the blower to the new fitting. Care was
taken to ensure that the drain is downhill the entire way. It gets close to
horizontal at the cover, but even there I was able to maintain a few degrees
of downward pitch.

Waiting on Mark for the last machined component (front plate for the
supercharger mount), and then its time to fire it up and begin tuning.

-Scott

Glad you are happy with your fabrication to date.
Luhn made ~ 863 HP with a 455 engine at 5300 rpm years ago.
Should be a fun vehicle to drive and very easy on parts.

No more than 27 degrees of total timing under boost.

Tom V.

Thanks for the input Tom, that touches nicely on the next phase of the project,
which I'm working on in parallel - tuning the PCM for boost.

With the naturally aspirated tune I have in the GM PCM now, I'm running
~12.6-12.8:1 AFR at WOT, and 33 degrees max timing (3300RPM on up)

The motor uses Edelbrock aluminum heads ported and prepped by Butler
back in 2007 when I built it. SCR is ~9.85:1. Cam is a hydraulic roller with specs
nearly identical to Old Faithful.

Are you recommending 27 degrees max based on my initial target of 7-8PSI?
I have a timing adder (retard) vs MAP table so that I can progressively pull
timing as boost builds.

Similarly I have a commanded AFR vs MAP and RPM table so I can bring the
AFR into the low 12's and even high 11's as boost builds. For 7-8PSI, I'd tend to
not go much richer than ~11.5, but would love to hear from others on both the
question of timing as well as desired AFR vs boost for this combination.

-Scott

27 degrees with no retard in the box.

Find the happy point for the timing (less than 27 degrees) or computer retarded for the
different boost levels. You will find it very hard to stay at 7-8 psi once you are driving the car, LOL!

John Clegg's 64 Pontiac Race Car used a simple "box" with timing pulled in 3 degree steps. You should be able to do much better with your electronic timing capability.
11.5 is a great Air/Fuel ratio to get dialed in initially.

Tom V.

Made more progress in the garage today. The air intake side of the blower is
now plumbed, and I made some tweaks to the boost side as well. Still a few
vacuum lines to run and a bit of wiring to tidy up, but its getting there.

WE -h-o, supplied the modified timing cover with our Turbo kits. we filled the void below the bottom timing cover bolt with weld and drilled an tapped for a fitting.
As low as you can go without putting a bung in the pan.

Man this is such a cool project. Keep the pics coming.

GT

The front supercharger mounting plate finally arrived, so I was able to wrap up
the install and get the belt installed. Pics of the final install are attached. I have
the initial 2-bar tune in the PCM and will try to get it out to log some data this
weekend. Really looking forward to seeing how it pulls!

That's bada$$!

I had a chance to go out for a test drive this past weekend, and could not be
more pleased with the results. I still need to get the tune dialed in, and had
things setup intentionally on the rich/conservative side, but did get on the
throttle a bit. It pulled nicely - gave it 80% throttle and ran it up to 4400RPM.
Indicated boost was 7PSI and rising. AFRs were in the mid 11's, and injector
duty cycle was passing 85%, which is no surprise since I still have my 42#/hr
units installed.

Next order of business is to order up a set of suitable sized injectors. I'm leaning
towards 80#/hr just to have plenty of margin. I like the ones sold by Ford
Performance parts as they have full datasheets available, making them
especially easy to calibrate.

New in-tank fuel pump is also on the way - I settled on the TI Automotive
F90000285, which ought to be plenty for my goals.

More work to do, but very happy with the direction things are headed.

The TI Automotive F90000285 in-tank fuel pump is an excellent fuel pump.

Tom V.

Super cool build! The V7 YSI is a fantastic supercharger. We ran one blow-thru on my friends Buick 455 for years.

Another few weekends pass, and more progress to report. I was able to swap
in the 80#/hr injectors, and they calibrated perfectly. For those interested in
saving a few $$$, you can buy Siemens/Deka 80# injectors directly and still
use the LU80 injector data.

With the larger injectors installed, I've run the motor up to 5000 RPM and am
making 10+PSI. Everything about this combination feels great - AFRs are still
in the low 11's (more fine tuning to do), and over all streetabilty is fantastic.

I'll drop the tank this weekend and swap in the new TI Automotive pump. Its
going to be rainy here all weekend, so might as well make the best of it.

Once that's complete, I'll get a few full-throttle pulls done next week and see
where things land for peak boost. Plan is to set my shift points to ~5800RPM
and see how the airflow and IATs look in the datalogs. This is one of those
times when I wish I lived out in the middle of nowhere - its a bunch harder to
find safe places to do this in the outskirts of Boston.<g>

This all of course has me thinking, how much boost is safe for this
combination? I'm wondering what others are running on their street cars
on pump 93 octane?

-Scott

We ran our "Mule" (at work) 4.6L 4 Valve engine at work with the #82-83 Bosch injectors
and the V7-YSI Vortech Supercharger for years (and made 820 engine HP).

I advised them on the EFI fuel system and fuel pump.

730 rear wheel HP on an accurate dyno.

Tom V.

I was able to get the new fuel pump and new Holley Hydramat installed this
weekend and go out for a quick ride to assess the results. The very first thing
I noticed is how QUIET this new fuel pump is. Its not like the Walbro 255LPH
unit I removed was noisy by any means, but the new pump is barely audible.
I like to think that speaks to its build quality.

To make the install in the stock tank a bit easier, I ended up taking my old
TanksInc 5-hole fuel level sender, and retrofit it into my stock tank in the flat
area just forward of the stock sender opening. By doing this, I removed the
burden of having to fit both a sender as well as the pump into the stock
opening. This made the rest of the install a breeze.

I did a few full throttle pulls (no laptop, just the wideband in the dash), and the
AFRs are in the low 11's to high 10's near redline, so I have a bit of cleanup to do
in the VE tables. The good news is that the fuel system had no trouble
keeping up, so I'm going to call this update a success.

-Scott

I've been having lots of fun dialing in and just driving this new combination.
Unfortunately, I'm noticing that my used/self built 4L80E is showing signs of
struggling a bit with the new found torque. I'm seeing indications of slippage
on the 2-3 shift at full throttle. It started happening as I really got the AFRs
dialed in at the upper RPMs, which tells me I'm making more torque than this
trans can handle. I can't really complain, I installed it 6+ years ago, and its
been perfect during that entire time.

So, I've made the call to Jake's and am in line for a new 4L80E. I've elected to
add the optional BOP bellhousing just so I can eliminate my Chevy to BOP
bellhousing adapter and flexplate to converter spacers. I'll end up rebuilding/
freshening the unit I pull out for another project. A buddy of mine has a 65
Riviera where I think my old 4L80E would be perfect.

So, for at least the next 12-14 weeks, I'll keep my foot a bit out of the throttle
and just cruise. I'm sure I'll have another update once I swap in the new
Jake's transmission.

-Scott

11 months is a long time between updates, but I wanted to let everyone know
where things are at! Since I last posted, many updates have been made to the
Bonneville.

First, my new Jakes Stage 2 4L80E and billet torque converter arrived, and they
have proven to be well worth the wait. For those looking for the ultimate in an
electronic overdrive, look no further - Jakes has you covered.

In addition to getting the new 4L80E installed, I also fabricated a new 3" mandrel
bent exhaust to handle the flow of the new boosted 457 engine. Nobody makes
a kit for a '70 fullsize, so I had to piece it together from bits sourced from RARE
and Flowmaster. The downpipes were from an A&F body kit, while the tail
pipes were intended for an A-body. With some creative fabrication, I made it
all work.

The car also got QA1 coilovers at all 4 corners. Once again, there wasn't a bolt
in option, but some creative work in the catalog yielded parts that were close
enough. I'm now fully adjustable at all 4 corners.

The last change was to update the throttle body and intake elbow to a 102mm
capable setup. At the same time, I also upgraded to a Gen4 cartridge style MAF
that would allow me to meter airflow up to 1024g/sec.

Its all still running on a P59 PCM, but with closed-loop wideband fueling from
an AEM wideband. Rear tires can be vaporized at will, which feels all a bit
childish and fantastic at the same time. Driveability and overall performance
are amazing - no complaints.

The next small project is to add a fuel composition sensor. I don't have E85
widely available locally, but the sensor was cheap, and its easy to plumb in,
so I'll add it just for kicks.

I'll add some pics of the exhaust and suspension updates soon.

-Scott

Coilovers front & rear

More coilover pics

3" mandrel bent exhaust fabrication

More exhaust pics

car is amazing excellent hot rodding!

To say that Scott is a genius would be an understatement.

Looks great! Enjoy the boost.

Have you run this car on the dyno yet? What size pulley and how much boost are you running at the moment? 2 or 4 bolt main?


Sent from my iPhone using Tapatalk

Thanks for the link Scott. Am not on PY as much as the old days. Your build is very cool and I love to see guys doing nice upgrades using real Pontiac Power.
Best to you

Craftsmanship! It looks very nice under there. 3" exhaust is not easy to fit on our old Pontiac's. Look forward to seeing more in 2025. Nice work.