Building 350 For Boost. Help

[Adi0o0o]

im fairly new to Forced Induction. i know the basics and what not. im very good at turning wrenches, however, i want to ask you guys for advice.

 

i'm building my engine,buying part by part. im planning to buy 2.05 alluminum heads from Patriot. can i have any advice on what you recommend the compression for the Pistons? and what Cam i should run? im trying to make this engine s/c'ed with a 6-71 blower.

I'm not sure on the tranny yet (auto vs 4 or 5 speed)

 

 

thanks for the help

[Adi0o0o]

come on, 13 views not ONE reply?

[BRAAP]

Sometimes a post will go unanswered for 24 hours, 13 views and less than one hour isn’t anything to really get excited over, please be patient.

 

You did come to the right place for your questions, though some more details would help. Bait the hook really good and you’ll attract all sorts of boosted V-8 fish from this pond. Really, there are WAY too many unknowns to offer any real direction in regards to parts. You’re going to have to meet us part way here. Please give us a LOT more detail about your project...

 

 

1) Any more details on the heads that you want?

2) Is this a race car, street car, show car etc?

3) Are you planning to run some form of intercooling with the 6-71?

4) Are you planning EFI or carb?

5) What emissions requirements do you need to meet?

6) Any other details/goals you are trying to achieve with this car?

7) Pump gas, race gas, E-85 etc?

 

Depending on what kind of power plant you are building, (i.e. the blower being just for show or you are planning to run sub 10 second time slips), will dictate what parts you should choose. Budget is ALWAYS a concern as you could easily wrap up $10,000+ just in the engine alone, no including the parts and fabrication for the V-8 conversion into the Z.

[Adi0o0o]

heres some info +links

Answers to your questions ar numbered in the order you asked.

 

1.http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=016&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=260124760064&rd=1,1

 

2. I'd say in between a race car/street car. i dont want a Daily, but not a weekend warrior. something that is FAST, but still drivable every now and then on the road.

 

3.No Intercooling

 

4.Im planning Dual Carbs. My choice would be Carter AFB

 

5.No emission requirements , Florida

 

6.Project car with my dad, ill gather the needed info about F/I and he'll put it together and etc

 

7.Pump gas

[dustin280zx]

why a roots blower?

[BRAAP]

Ok, why not a roots blower?

[COZY Z COLE]

Ok, why not a roots blower?

 

 

No kidding.........I've spanked the best of them in Fairfield,Ca. and have started on the ones in San Angelo,Tx. I've just the 144 WEIAND blower and it's a torque monster...Just ask dr.hunt after a little ride with me in Apr.

 

Adi0o0o... Look in my photo album. Be ready to spend the money on that motor and other mods... I'm past $30,000 in the total car package and no end in sight

 

 

LARRY

[dustin280zx]

I wouldnt think the street manners of a roots would be very good compared to a centrifigal or turbo.

[Adi0o0o]

well, the reason why im saying a 6-71 is becuase my dad would love that, a huge blower sticking though the hood. I,myself woudl rather has a smaller blower, under the hood. and a much mroe street car.

 

 

however, back to my question above.

 

also, i dont see how in the world id spend $30,000 on an engine if my dad does all the work himself. the most expensive part would be the blower (2,500-3,000)

[Adi0o0o]

also, this might be a pain in the butt to ask....

 

can someone ALSO provide me with thier set up?

id like to know what you S/C guys are runnning.

 

please give me a few details on the car

like, is it street friendly, etc etc

 

 

maybe a 6-71 is overkill....

[BRAAP]

The chambers look nice on those heads.

So you are building a 350, (4.00 bore with 3.48” stroke, more than likely at least .030” over bore?)Due to the 64 CC chambers, you will need a dished piston. There are a couple routes to take. If you keep this mild, i.e. low boost levels, mild cam, you can run one of the KB Hypereutectic pistons, or if you plan to run it hard, then I’d recommend a forged dished piston. Because of the nice chambers those heads have, I’d strongly urge a D-shaped dish in the piston to retain some squish.

 

With blowers, as well as Nitrous engines, generally, there is more bias towards the exhaust valve. For example, a supercharger specific SBC cylinder head will have 1.95” Intake valves and 1.60 exhaust valves, and even closer sizes. If the head can’t be built with a supercharger in mind, we tend to band aid the added exhaust flow with a more aggressive exhaust lobe. That would be a radical split duration cam. Speaking of cams, for supercharged applications, remember to keep the lobe separation wider than it would be for an N/A application. Between 112-116 is common, 114 is a good all around mild to moderate blower cam LSA.

 

Below are few options for a budget minded 350 SBC blower build up.

 

 

Here are few off the shelf pistons, $400-$573 (most cost effective vs custom)

KB Hypers, 22cc D-dish, with 64 CC chambers approx 8.5-8.7:1 compression. (You are limited to 5.7 rod length with these pistons, but they are affordable for mildly boosted applications, i.e. don’t abuse it too much)

1/16 ring pack, 5.7 rod.

http://www.kb-silvolite.com/performance.php?action=details&P_id=224

 

same as above but with 5/64 ring pack

http://www.kb-silvolite.com/performance.php?action=details&P_id=153

 

Forged for more severe duty…

TRW forged equivalent, 5.7 rod, 22cc D-dish.

http://store.summitracing.com/partdetail.asp?part=TRW%2DL2441F30&autoview=sku

 

SRP 5.7 rod 24 CC dish.

http://store.summitracing.com/partdetail.asp?part=SRP%2D139633&autoview=sku

 

For a 6” rod, I couldn’t find anything with enough dish for a roots blower and 64 CC chambers. That would be custom pistons and if you call JE, Ross, Wiseco, etc, they will have a common blower piston for a 6” rod for your application, though plan to spend more than $600 for the set. Blower pistons have a Dish and the ring pack is further down the piston for heat reasons.

 

 

 

Rods.

Scat I-beam rods, nice mild to moderate street rod.

http://www.cnc-motorsports.com/product.asp?ProdID=1118&CtgID=1133

 

Crank, stock will work, Scat offers a decent cast Steel replacement cranks.

 

Here is Comp cams blower cam, 115 LSA, would work better with a cylinder head built specifically with a blower in mind.

http://store.summitracing.com/partdetail.asp?part=cca-12-400-4

 

 

That should get you started…

[Adi0o0o]

wow, thank you. thats awesome advice.

 

 

*******ALSO anyone who wants to recommend a v8 supercharged setup, PLEASE DO. but include details. The S/c Doesnt have to be a huge 6/71. thats just my dads preferance, he is old school.

 

keep in mind its for a streetable/weekend drag car. FAST.

[BRAAP]

I wouldnt think the street manners of a roots would be very good compared to a centrifigal or turbo.

 

Haven’t heard that about roots blowers before.

Street manners wise, ALL crank driven super chargers are pretty docile street manners wise, the roots offering the most predictable flattest torque curve of all superchargers.

 

Boosters 101…

 

 

Roots Blower, (positive displacement super chargers). Roots blowers generally deliver the flattest power curve, no lag, etc. It is generally viewed as the most drivable of all the unnatural aspirators due to its predictable demeanor, flat power delivery, and generally mild cam specs for optimum super charger power, i.e. wide LSA. They generate GOBS of torque at idle all the way through redline.

 

Centrifugal blower/super chargers are RPM dependant in regards to boost. Down low, depending on the set up, they will generate little to no boost, and the boost level will increase with RPM. In graph form, the Torque curve will resemble a typical Horse power curve, rising from idle to redline.

 

Turbo chargers. These are the most complex, yet most efficient at turning fuel and air into tire smoke. Depending on how the application is built and set up will determine how the power is delivered, throttle response, lag, etc. They do have a high initial and long term cost. Turbos can be set up to be quite drivable, again with great attention paid to the design and tune of the project. In a cost no object Turbo project with lots of cutting edge anti lag enhancement’s, Turbos are wonderful.

 

Nitrous. This artificial induction of oxygen in the form of Nitrous Oxide from a bottle via nozzles in the intake provides instantaneous power. It is fun, harder to modulate the power and you have to refill the bottle when it’s empty. Great for short quick squirts up the road.

 

Where a Turbo works best for one application, a Roots blower works better in another, and a centrifugal super charger works better in another. It just depends on the application and where the builder/owner is willing to make his compromises in regards to acquiring artificial aspiration.

[BRAAP]

wow, thank you. thats awesome advice.

 

 

*******ALSO anyone who wants to recommend a v8 supercharged setup, PLEASE DO. but include details. The S/c Doesnt have to be a huge 6/71. thats just my dads preferance, he is old school.

 

keep in mind its for a streetable/weekend drag car. FAST.

 

 

 

Here is my Roots Super Charged SBC build up.

 

http://forums.hybridz.org/showthread.php?t=115326

 

Currently, everything is in hand except for the cam, headers, and coils.

 

Scat cast steel crank, Scat Rods, KB Hypereutectic pistons, (because of my driving habits, I probably should’ve stepped up to either the TRW L-2441 or the SRP forged 24 CC dished pistons), Eaton M-112 super charger from a V-12 Jag, Trick Flow 195 Duttweiler signature heads, Hamburger shallow road race oil pan, ARP main studs, ARP head bolts, Fluid Damper, Centerforce Flywheel and CF II clutch, T-56 6 speed trans, Ron Davis Radiator, WOLF EFI system that will also control 8 LS-x ignition coils. Haven’t settled on the cam or headers yet. Ideally I want a 180 degree 1 ¾” primary headers because I’m weird that way, but will most likely end up with 1 ¾". Shorties.

[Adi0o0o]

SITE ROCKS, I LOVE THE INFO!

 

keep em cominggggg

[jnjdragracing]

Hey Adi0o0o,

 

You can check out my website at www.jnjdragracing.com, look at www.jnjdragracing.com/engine.htm, It shows my engine build for a 6-71 roots supercharger. You will need a strong bottom end, the 6-71 makes a lot of instant power. 350 block must have 4 bolt main, main studs, head studs, good rods, good crank, crank needs to have double keys.

 

If you are interested in truly doing a 6-71 you need to call JR at RBSSuperchargers 530.292.3368, they do all my supercharger work now. They have good prices on blowers, used blowers etc.

 

If I can help let me know.

 

John

[BRAAP]

One of the masters has spoken. You can ignore everything I’ve posted. When the boys of JnJ speak about Supercharged SBC’s, take good notes. There is another SBC Savvy engine builder/machinist on here by the name of Grumpyvette. These guys will steer you in the absolute right direction, and don’t second guess their advice. You can rest assured their advice comes from years of experience building, driving, and pushing the envelope to find out what does and does not work.

[jnjdragracing]

BRAAP, everything you said is true... I all depends on what he is building. I built my 350 for street / strip duty, but have been doing only strip. I was amazed at the power HP and instant torque the roots blower made. I did alot of home work before my build.

 

I would call Grumpyvette a master and yourself. I just know the old style SBC well and that’s the engine of my choice. I have had a lot of years of experience and knowledge of them and how to make them run. I am just a simple plain country Southern boy who likes to drag race.

 

You made some excellent points about exhaust, the blower has no problem with getting fuel to the intake side, but you have to be able to get the exhaust out, so exhaust is the restriction in a supercharger application. Need to run the biggest exhaust valves / headers you can manage. Our cam is on a 110 centerline with a duration is 255/270 lift is 572/574 with 1.5 rockers, I am running 1.6 ratio rockers so it gives me 610/612.

 

Heat is also a factor with a roots supercharger, the more boost you give it the more heat, so you have to give up something to get something, you have to find the combination that works best for your application if you are running gasoline. If Alky is the fuel then poor on the boost......

 

BRAAP thanks for the kind words...

 

John

 

One of the masters has spoken. You can ignore everything I’ve posted. When the boys of JnJ speak about Supercharged SBC’s, take good notes. There is another SBC Savvy engine builder/machinist on here by the name of Grumpyvette. These guys will steer you in the absolute right direction, and don’t second guess their advice. You can rest assured their advice comes from years of experience building, driving, and pushing the envelope to find out what does and does not work.

[Adi0o0o]

im loving the information, please ANYTHING you think that would help me get closer to my build, please spit it out. THANK YOU GUYS, you seem to know crucial details. awesome, thanks again. As soon as my dad gets home im going to have him take a look at this thread. thanks!

[dr_hunt]

Boost is boost as far as the engine is concerned.

 

My blow through twin turbo build is a 350 production 4 bolt block short filled with main and head studs, factory steel crank, Eagle 5.7 rods with L-19 bolts, TRW forged blower pistons (8.1:1 compression calculated), AFR 227 fully cnc ported heads with 2.10 intakes and 1.6 exhausts, comp custom roller 240/250 .630/.618 112 LSA, gear drive, fluidampr, sfi flexplate, victor jr.

 

Definately not a daily driver.