Team Chevelle banner

Boosted Beaumont Build

44K views 413 replies 30 participants last post by  GoFast Beaumont 
#1 ·
So I thought I’d start a thread on my winter build. Every year I do something to upgrade the car.

Little history, the car is a 1968 Beaumont Custom, I have owned this car since 2002. It laid rest in a field for 4 years when someone completed a semi restoration on it. The winters we’re pretty harsh in the area so now it definitely has some patina. This car to date has been threw 4 motors 5 transmission and 2 differentials. It started out as a Smokey 350 motor with a 700r4 and Corp 10 belt setup. Now it is a 502, T56 Mag, s60 combo. There is also an array of suspension and chassis upgrades to get it where is is today. Overall the interior and exterior remain stock.

So this leads up to this winters upgrades!

After completing Drag Week 2018 I have realized that if a guy wants more power you don’t necessarily need a larger motor, just cheat with some boost. Originally when I got the 502 I was gonna boost it but held back as my power goals were low for boost. For the builds end outcome I am looking to achieve a dyno proven 800-850 crank horsepower/torque between 5-5500rpm. I am not sure if this is realistic but we will find out. I am limiting myself to this number as the bottom end will not support anymore than this.

The combo will be a single (twin scroll) Garrett turbo
Single wastegate
5” down pipe with a single 3.50” exhaust and boost activated cutout
Water to air intercooler
GM 502 short block
AFR305 heads
Straub hydro cam
Victor intake
Holley super sniper
New LSA twin disk clutch

All said and done hopefully I can complete this before Rocky Mountain Race Week
 

Attachments

See less See more
2
#2 ·
How big is the turbo?

Either way, love the car. Being from Ohio, we had a few Beaumonts running around. I have seen exactly one in my 34 years in Flariduh!

Sorry bud, I see way more that 850ish horse in that combo if the tune is right. I would have to feed it corn fluid and shoot for 25 pounds of boost.
 
#4 ·
How big is the turbo?

Either way, love the car. Being from Ohio, we had a few Beaumonts running around. I have seen exactly one in my 34 years in Flariduh!

Sorry bud, I see way more that 850ish horse in that combo if the tune is right. I would have to feed it corn fluid and shoot for 25 pounds of boost.


Turbo is a Garret GT4202,75mm, which is a fairly decently sized turbo but for this build it is consider small by most. I will most likely be out of the efficiency zone but should provide very quick response for a 90% stick shift street car. Like any upgrade the initial cost is a killer and I got this thing less than you would buy a *********** turbo at, plus side is that it is brand new never used, ready for abuse. So the plan is to build things keeping in mind it will be upgraded in the future.
 
#6 ·
That car is badASS, Chris! <img src="http://www.chevelles.com/forums/images/smilies/thumbsup.gif" border="0" alt="" title="Thumbsup" class="inlineimg" />

Are those wheels the Nascar/racing slotted steel wheels? I like those.
Yes Bassett wheels, one of the few non-dot approved parts.
 
#7 ·
Well I got the passenger side manifold/header completed. Just have to finish weld it out. To my surprise this manifold actually creates a scavenging effect, well at least with compressed air running down it. If pushing on tube 7 it will draw on 3&5. And conversely for the other. Tube 1 is solo and creates very little scavenging nor does it see much at all. Spark plug/boot clearance is 10-fold over the headman headers! As well the steering shaft. I see it does come close to the rag joint, might have to opt for a universal there instead.

Material I choose was steel, flanges are 3/8” thick with 16gauge tubing. Hopefully it will last.

Now to figure out how to weld this without warping everything.
 

Attachments

#8 ·
Been a little slow on this build but here is a picture of the 2.5” exhaust crossover from driver side to passenger side. Utilized a 4” long expansion joint, these allow for approx 5/8” deflection. Cross over sits approx 1-1.5” below the oil pan but just slight above the crossmember.
 

Attachments

#9 ·
Turbo mount built! Just need to finish up welder big and clean it up. Will have to redo the oil cooler lines on the rad. Clearance is about 1.5” from hood to compressor housing, hopefully that’s enough not to melt anything. Should be able to do a full 5” downpipe. Fender well clearance is a nice size if I decide to go to a bigger A/R housbig or bigger turbo in the future. As well I am thinking the alternator will fit back where I had it mounted before.

Now I can finish up the cross over, build passenger side manifold/header, and then the 60mm wastegate.
 

Attachments

#10 ·
Well got a solid 2 days in on more fabrication work. Built the passenger side header/manifold. Turned out well. Spark plug clearance again way better than long tube headers.

Completed the exhaust cross over and tied everything into the turbo mount/flange. Turbo mount is strong enough to support the turbo without the help of the exhaust, so hopefully this will minimize and cracking that could occur.

So far it is looking like a 5” downpipe is completely possible.

Up next will be the wastegate piping and plumbing. I will be doing a 2 into 1 wastegate setup.
 

Attachments

#11 ·
Quick shot of the wastegate merge pipes. This is a 2 into 1 adaptor. I am going to run a single 60mm wastegate. Reading a little it should be easier to work with as I don’t have to worry as much for syncing 2 gates or non-equal pressure in the banks, and less pipe work to get it back into the downpipe.

The waste gate of choice is a Turbosmart Gen V 60mm watercooled wastegate.

Each pipe is 1.75” diameter merging into a single 2.50” pipe to the gate.

Hopefully this does not effect spool times as the turbo is a twin scroll, my initial thoughts are ‘no’.

With a wastegate this size I should be able to dial boost down as low as 3-5lbs and as high as I want to take it. The turbo matchbot calculator says I would need approx. 50-55mm.
 

Attachments

#12 ·
Well I got a 5” downpipe/exhaust fabricated, not sure how well it will work. It is pretty close to the valve cover, about 1/4” away. I don’t know if it will bake the oil on the inside or not, but will give it a try unless someone says something concerning.

I am thinking the valve cover will need to be ceramic coated with all the exhaust. Mayby wrap it as well.

Could always throw in some dents and give it clearance 🙂
 

Attachments

#14 ·
WOW Chris, just WOW! I missed a chance to buy a 68 from a fella with teh handle "snake" here back in maybe 2004-05 for 6K ( US and CDN were near par) .

Boy, if it turned out half as nice as yours..... one of my few regrets.....68 Beaumont, and a Russian-speaking redhead in the Army.....! :) Woulda , coulda, shoulda, ....

YOU DOING IT!
 
#15 ·
Well looks like I got a deadline now. Registered for Rocky Mountain Raceweek! I will be racing in stick shift class.

Once all done I will be driving the Beaumont to the event and back, no trailer either. Should be around 4-4500miles in total.
 

Attachments

#16 ·
I like it :)

This will be a fun Chevelle.
When you have the time post more pics of the car....the patina and the interior.

Dan
 
#18 ·
Well finished up the hot side of the wastegate. A 60mm wastegate is massive, but it fits. Hopefully I can get the vacuum pump beside the wastegate and water pump.

As well on the crossover I changed the expansion join from a 4” to a 6”. I was always told run the biggest one year u can fit and since I have the room. I will run the smaller 4” expansion joint for the wastegate to downpipe cold side.

Little slow on progress with all the welding required but it’s coming together.

Going to move on the check valve spring pressures, oil pan modifications, and manifold change.
 

Attachments

#19 ·
Looking good. You should bring that beast to Mission for some sea level drag action. The "Old Time Drags" is always a good time. Everything is 1972 and older. And as others have mentioned, excellent choice in beers. Still one of my favorites. :beers:
 
#20 ·
Well a Drag Week friend and local-ish guy in the area helped me out huge today with my clutch. Mayby some seen a post of a Mcleod street extreme that got hurt last year, as a result I was in need of a upgrade. So in some quick talks I got a used Mcleod twin disk RXT 1200. I will get further into details about flywheel weights and what not a little later as well what I have learned. Pretty stoked about it, I was original going to use a LSA/LT1 dual disk I have kicking around but this route will save a ton of time. I may still go that route down the road but let’s see how this works first.
 

Attachments

#25 ·
so I have been keeping track of clutch setups I have run in the past and current. see below for stats


McLeod Street Extreme (Drag Week Setup)
Pressure plate 20lbs
Clutch disc 5lbs
Aluminum flywheel 14lbs 8oz
Clamp load 2400lbs +/- 5%

Centerforce II
Pressure plate 25lbs
Clutch disc 4lbs 6oz
GM nodular Iron 31lbs 2oz
Clamp load 2800-3200lbs


Mcleod RXT 1200
Pressure Plate 12.25lbs
Clutch Discs 3.17lbs X 2 = 6.34lbs
Steel Flywheel 29.43lbs
Adapter Plate/Mid Ring 5.86


My first setup was the center force II and the entire assembly weight 56lbs, this resulted in the easiest to drive. My second setup was the Street Extreme at 35lbs, little harder to drive, way quicker RPM, not the greatest at the strip. The new setup will be a RXT with a steel flywheel at 47lbs. I'd expect this to be a great middle ground, well see how well it works at the track.


I will honestly say for a real street car despite the power levels and your into the drag strip, you will need a steel flywheel. Getting a 4000lb race weight car to leave the line half decent requires some stored energy. And after talking with fellow racers it seems the trend currently is to run big flywheels and small clutch setups, it seems to yield a great medium in leaving the line and accelerating your car.
 

Attachments

#22 ·
Well here’s the manifold I am running for starters. It will be a edelbrock super victor with a 4500-4150 adapter. This should be the best ‘all out’ manifold. I have read a lot where people of a similar 502 build say they gain a lot over dual planes, so I will give it a try. I have welded in a -12AN o-ring port for the vacuum pump. This will also be where I will mount the vacuum regulator. I tried in the valve covers for drag week with poor results. It was constantly sucking oil out. Mounting it here has the least amount of oil splash with the valley tray in place. I also did a minor port job to eliminate the valley dam at the plenum to port that plagues these things. Should help with flow and fuel distribution a minor amount.

I am think in the future I may swap to a dual plane or modify this super victor so that I can fit everything under a stock hood. Mayby even one of those crappy edelbrock torquer 2-R twisted intakes. For now it will be the cowl!

As for those that say you can’t run a vacuum pump on the street, I will say after running one I wouldn’t go without it. Oil was instensely clean and the pump itself has basically no wear after 1800 street miles.
 

Attachments

#23 ·
So after some thinking I re-made the steering shaft. It was really close to the rag joint and did not want to risk melting or burning it while driving. Went with all Borgenson hardware to complete the task. I will say these are really nice pieces. The fit onto the splines is a lot better as well there is a lot more spline contact. The lower joint is a standard u-joint with no isolation to maximize clearenece and the upper one is a isolating one. I also picked up a crush style steering shaft. Surprising this new one will collapse 1” more than the old one.
 

Attachments

#24 ·
Here is a comparison to the two manifolds. Last year I ran the edelbrock C-454 with a dominator, this year will be a edelbrock super victor with 4150-4500 adaptor. In there base form the super victor is 1.25” higher than a c-454. Ports are the same size between the two. Once the adapter is in place it will make it 3.00” higher than last years setup

As well here is a couple pictures on a valve spring tester on the head, check the seat pressure and in this case I can check open pressure. Anyone with hydraulic lifters be aware the lifter can ‘pump up’ giving a faulty reading. Read it right the first time or back the rockers off to zero lash and check them. Good thing for me these PAC racing springs are within 10lbs of seat pressure. Well under 10% difference between them all.
 

Attachments

#26 ·
Also remember your twin disc is only 9.688" which brings the weight closer to the center line, thus less inertia.

My old setup was:

Centerforce Dual Friction - 30.2 lbs
GM cast iron Flywheel - 26.5 lbs
Total - 56.7 lbs

Very easy to drive around and get off from stop lights. Could even launch in 3rd gear.

New setup:

McLeod lightweight billet FW - 24.8 lbs
McLeod RXT twin disc - 23.8 lbs
Total - 48.6 lbs

I get chatter with this clutch which requires more rpm to get it moving. Note, this is a ceramic disc. I don't notice any real difference in accel or decel.

Note: I have a T56 Magnum 2.66 gear and a 3.31 rear gear.
 
#28 ·
Heres a little mock photo of the intercooler. It measures 24”x12”x4” core. Thinking I could fit a 27” wide but may settle for this one. Had to cheat to get it in and cut the rad support a bit to fit the charge tubes. So far to date this is the only cuttingnon the car. Was really hoping not to do this, but my mount under the rad support idea just didn’t look effective. This intercooler has to weight as much as the radiator. Should work good and support 1000hp. 3” charge coming in, 3.5” charge going to the engine. Hopefully this does not effect cooling drastically or at least when cruising at 85mph!
 

Attachments

Top