Confuzed1

iTrader: (4)

Hey all,

Just flipping through the “Power Adder” boards, and I’d like to get some opinions from the blower guys here. I have plans to once again pull the engine out of the car for other issues (oil burning), and I’ve been seriously considering going a whole different route with this engine.

You can see the setup I have in my sig. It’s not bad and does make some power, but I want a bit more, so I’m looking into either converting it to a blow-through setup using a centrifugal blower, or possibly a draw though with a roots type, even though it’s less efficient. Since I have a few carbs lying around, I see no reason or advantage in switching to fuel injection. I’m hoping to achieve around 500 plus HP and keep the redline no higher than 5500 because I’d like to retain my hydraulic roller valve train and stay totally streetable. Currently the compression is around 9.3:1 using dished KB 147 pistons (Hypers), and the iron eagle 200cc intake, 70cc chamber heads. –So, the question is, what will I need to change on my setup to make it a reliable, streetable setup with a blower?

PS - and yes, I plan to do alot more research before I actually do this. My goal is to do this right the first time.

Confuzed1

iTrader: (4)

Just to add, I roughly figure I'll have to change rings at the least, pistons at the most. I already have about 4K in the engine, so I'm hoping the bottom end should hold up fine. I'm in the process right now of pulling the heads and having them checked for bad valve guide clearance, or cracks/penetrations during the porting job. If they turn out OK, then it's something in the block because I've checked everything else conceivable I can think of - multiple intake gaskets, different intakes, etc. to find the cause for it burning oil. If need be, I'll get a Motown block and start again (saving block internals) and possibly go the supercharged route.

So looking for ideas here.....

rob_m

I'm a turbo fan myself but if you are set on a blower go centrifugal.

1. More thermally efficient, less heat=less stress less chance of detonation.

2. You already have more than enough low-end torque to annihilate the tires.

3. You can run an intercooler to increase power and reduce heat.

You only need a little more than 40% Hp increase to put you at 550HP. That's a MILD intercooled setup. If you're thinking about swapping pistons, I'd definitely lower the cr and go forged. I've read good and bad about hypers, but that engine is capable of sooo much torque you'd want forged. That's my 2c.

Confuzed1

iTrader: (4)

OK, I waited to respond until I did a bit more reading.
Rob, I agree - the centrifugal style compressors are more efficient and I realize that. One of the main reasons I'm considering forced induction is for the better streetability - so to speak. Idle to 5500 RPM powerband, smooth idle - a sleeper - so to speak lol.

I'd like to see 500 RWHP or better, so I don't think I'm asking too much out of this 400 SB. I'll settle for that. Not looking for 800 plus HP that twin turbos or high end centrifugal blowers.

The Weiand 144 and 177 blower setups seem pretty sweet. But I'm afraid I might have to spin it too fast to make meaningful boost on a 400.

DIGGLER

iTrader: (1)

i would probably freshen up the motor, put it back in the car, and do a vortech s-trim or other centrifugal blower. simplicity and efficiency!
i would probably also get a blow through carb. can probably run 8# boost safely with your compression and iron heads.

Confuzed1

iTrader: (4)

Diggler - Yes, I plan to set the engine up for boost...actually I have no choice because the gapless rings I presently have won't allow for boost. Since I just finished buying a 750 Holley not long ago, I'd like to use it if possible, so I figured a draw-thru setup would be easier. Basically, here's what I want to reuse:

-Scat forged crank (3.75 stroke)
-Eagle 5.7 sir rods
-retro-roller lifters pushrods, rockers
-Holley 750 DP carb
-MSD HEI distributor

Things I know I need to change to run boost:
-Cam
-rings
-pistons

On "The bubble" (but I'd like to reuse if I can):
-Stock block (will reuse if no further overbore required)
-Dart heads (will change to aluminum only if I have to)

I'm not saying blow-thru is absolutely off the table, but after pricing blow-thru carbs, I'd rather adapt mine. What I've read seems to indicate I'll need to change floats and maybe block off the power valve, I should be good-to-go for the carb right?

From what I've read, aluminum heads will allow me to run 1 additional pound of boost.....but do I really need the extra 1 pound of boost to net what I want out of this 400 without detonation issues?

The S-trim blowers look awesome I agree, but I'm looking to keep my AC and power steering etc. -My AC compressor is on the driver's side, right where the huge S-trim bracket goes. Is the trade-off really worth it?

That's part of the reason the Weiand kits look good to me, but I need more opinions on this. I'd like to set the budget for doing this at 3K if possible.

Money really isn't the object, but I'd rather not have to sell half my N/A go-fast parts for a loss just to run boost if I can get away from it.

So I'm looking for a good reliable streetable setup reusing as many parts from the N/A setup as I can, but I'm willing to change for reliabilty if needed.

-There's alot of guys on this board here that run boost, and knows what works and what doesn't by trail-and-error. I don't have extra $$ to experiment, so I'm looking for advice on how I need to set this up right the first time.

DIGGLER

iTrader: (1)

maybe you could just sell your heads and get some alum. ones... maybe some vic. jr's or afr's or whatever.
i wouldnt be paranoid of the hpyper. pistons under boost, but you would need to be careful with your tuning. swapping to some forged ones would be great, though. super low compression ratios can start to get sluggish down low in the rpms, so try to run as much as you can safely get away with for a given boost level.

from my understanding, whatever you can run with alum. heads @10.5:1 compression, youd need to step it down one point in compression in order to run an iron head. they retain more heat in the chamber. the limit for a stock LT1 engine (alum. heads) is 8psi from an s-trim supercharger. thats roughly 10.5:1 compression with a hyper piston. ~110 rwhp increase over stock. ~360-380rwhp

Confuzed1

iTrader: (4)

Diggler - Thx again for the feedback on this, you've been a great help. I was really hoping others would also share thier knowledge that are running a supercharger be it roots style or centrifugal type, so either I'm not stating my goals clearly enough, or everyone is so into turbos that superchargers are too petty for them - just making that assumption judging by how many turbo threads there are on this board. Now, If I were building a 1/4 mile drag car, I'd go with a intercooled turbo (or 2) , but I'm not interested in 1000 RWHP or anything like that. -not the case here.

-I have a feeling if I said "building a twin turbo 400" as a title to this thread, I woulda gotton tons of responses. But complaining on my part isn't going to help anything.

Lemme try explaining my goals with this engine one more time:

-Looking for a weekend fun car, that is totally streeatable with a decent idle.

-Would like it to pull from 1500 to 6000 rpm's max. (I would only wind it out to 6K on "test-n-tune" days at rare occasions at the track)

-I'm not going to get stuck on what I want for HP, but I'm looking for 450-500 RWHP range, which should be doable on a blown 400 since it's putting out 390 FWHP N/A now...(which might be 340 RWHP)

-I'd love to retain all accesories including A/C if possible, but will reluctantly lose the A/C if it's the only way to acheive all the other goals.

-Already have plans to buy a Jongbloed hood (sp), or cowl hood, so underhood space won't be a problem hopefully.

-I'd like to retain as many parts from my current setup as possible, but willing to change if needed. Since the shop found nothing wrong with my heads, the shortblock is coming apart, so I'll go ahead and set it up for boost - any tips in this area appreciated.

-I've read alot of supercharging sights, but if there's more you know of with good info - please post em up!

Confuzed1

iTrader: (4)

OK guys – I'm narrowing it down now. After doing *some* research, (and I need to do a bit more, that’s why I’m posting), I decided to go with a ATI Procharger “D” series blower, and stay with a carb since I have a 650 Speed Demon and a 750 HP Holley available to me. Seems to be the best "bang for the buck", but I “think” I’ll have to bite the bullet and get rid of my AC which I don’t want to do, but I don’t really see any way around it…..if I want a intercooler that is. (and I do)

After doing a little searching, it doesn’t seem like the P600B is big enough for a 400 CID engine (I’ve read posts that you’ll only get around 4 psi of boost at 5K rpm’s with a 400)
BUT – I realize some of that depends on what my compression is and cam I have. I’d like to maintain around 8-10 lbs of boost. As said in earlier posts, only looking for Idle to 5500 RPM power band.

Some things I’m still looking to find out :

-I can’t seem to find a piston that will drop my compression below 9.1:1 static using 3.75” stroke, 5.7 rods and 72cc chamber heads. Seems like the only way to lower it is to go with bigger heads or custom pistons – right? And what about “quench” – I don’t want it to detonate, and I DO want to run pump gas.

-Trying to find out if I really need to switch to aluminum heads to prevent detonation at 8-10 psi IC boost level w/o detonating on pump gas? – Or will my Dart Iron Eagles work?

-Looks like some serious fuel system mods will be in order – Aeromotive fuel pump, -8AN lines, regulator etc…that’ll push the cost way up. Have’nt figured out the fuel requirements yet……Any suggestions?

-The cam I have won’t cut it for boost…..I’ll need something a bit milder with at least a 112 LSA correct? Think I’ll still achieve 450-500 RWHP?? (Not FWHP, almost there now)

For the most part, I *think* my bottom end will hold up (after I get forged pistons). I could go with the type of gapless rings that allow for boost, or should I just get standard moly rings and file to fit for boost. – which would you get?

I’ll give ATI a call next week to see what they say also, but I’d love to hear from the experienced guys here.

WheelsUp84z

iTrader: (2)

Ok here's my opinions. as far as compression and the likes. If youre only doing 8-10 psi then you should be plenty fine with 9.3:1 CR. That way, off boost it won't be a complete dog. If you want to run pump gas, you'll have to run a little less timing too. Intercooled Centrifigul would be the way to go. I like ATI (Procharger) and Vortech superchargers. The D1SC or S-Trim would be the choice for you're power goals. You'll be able to keep the Iron heads, no worries about that. Some guys are running 10-13lbs of boost on stock TPI's without problems if that tells you anything.

Rings: i would say go with the traditional file-fit kind just because i havent heard too many applications using the gapless with boost.

Cams: 112-114 LSA would be Ideal, a single pattern cam or one with a little more duration and lift on the exhaust side will help the air flow out of the chambers. I would keep the duration around 224* max for a smooth running street car. FYI Hydraulic roller cams can spin past 5500 RPMS easily, the reason you wouldnt need to is that the cam won't make the power past that point. LS1 cams are Hyd. Roller and they spin to 7k rpms like its nothing.

Fuel: On a blowthrough setup you're going to need a Boost referenced regulator, and a pump that will be able to keep up with you're application, its better to have and overkill fuel system than one that cannot keep up with your motors needs. An aeromotive a1000 or a Magnafuel 500 would be good. If you plan to run these on the street a fuel pump controller would make it last 10x longer.

Pistons: there are plenty of off the shelf pistons out there that will get you under 9:1 with 72 cc heads, but like i stated before, you can keep you're 9.3:1 and still be fine

Confuzed1

iTrader: (4)

First off, let me say that’s one heck of a nice ride you have there 84Z!!! (although it’s a 91?!?) Thanks for responding.

If I can get away with 9.3:1 with iron heads using boost, that’s great news! It sure beats having to sell these heads for a loss, and spending 1K plus for aluminum heads! I was concerned because I read somewhere that when using a carb, the fuel doesn’t atomize quite as well and may cause detonation problems, especially with iron heads. –But you’re right, people with TPI’s get away with it using iron heads – I didn’t think of that..

I asked about rings because I’m running TSS gapless rings presently, but they also sell TSI gapless rings that allow for boost. I’ll probably use the file-fit instead anyway because at least the clearances are totally under my control.

Seems like I might have the right idea about the cam then. I’ve read 4-5 degrees more on the exhaust duration helps with scavenging, so that’s what I’ll look for…
Torque has never been an issue with this engine (490ftlb. at the flywheel), and from everything I’ve read so far, I shouldn’t need to wind this 400 up over 6K rpm’s to make good power. Besides, having to rev past 6K on the street draws way too much attention. -If anyone has a particular cam that’ll do well with this setup – feel free to chime in!

If there’s pistons that’ll allow me to go lower than 9.1:1, I haven’t found them yet - or I’m not looking in the right places. So, if I can keep my Hypers on 8-10 pounds of boost, then I’ll do that.

I’ll start looking further into the Aeromotive pump and boost referenced regulators then. I’m a real rookie when it comes to boost, but I agree…I’d rather go on the “overkill” side, and not risk running lean. Besides, you never know – I may want to add a small shot of nitrous in the future. I’ve done crazier things!

Thanks again, and if you or anyone else has any thoughts - just jump in!

Confuzed1

iTrader: (4)

BTW...if anyone knows of any reference materials (Books, mags, internet links) pertaining to supercharging, please post 'em up!! As I've said all along, I want to do this right the first time.

Someone recommended "Maximum Boost", and it tells me everything I want to know - about turbos. I need supercharging info.

-Thanks in advance.

Confuzed1

iTrader: (4)

I seem to be replying to my own post, but oh well.

I got more info on Prochargers in the mail. I just got off the phone with them also. My concern is exactly which kit would fit my car, and allow me to retain my AC (if possible). My AC is on the driver's side. They say they have a bracket, but I'd have to switch to a newer "pancake" style compressor, and get rid of my old one.

It seems they have a new serpentine bracket kit I could get (for an additional price of $699.00), that will supposedly allow me to retain my AC compressor. I think that price is ridicoulously expensive for brackets even if they are "billet aluminum". Add that to the 4500 dollar "basic kit", and it starts looking pretty darn expensive. I plan to look close at Vortec blowers closer too after this.

Anyone know of any other options I have? I mean, if I go through the hassle of changing out compressors should I just get a serpentine drive off a 88-92 F-body and mount my AC on the pass. side? Heck, I'm not even sure it would work without mods. Kinda funny (or not)....if I had TPI, I could just bolt it on - but if you have an older thirdgen, it seems you're stuck with the "standard universal carbuerated kit or nothing...

-Any suggestions??

Trypt

I am sorry, I have nothing technical to add, however...

I was sold on adding a supercharger to my car, and really didn't even consider a turbo, thought of them as small-engine power adders and had an all around negative opinion about them.

But after posting on thirdgen.org about the type of SC to add, it took only a few days to start doing research on turbos, and perhaps a week more to totally forget about supercharging and focus completely on turbos.

I am just wondering, it seems that you don't want a turbo only because you don't want a 1000hp racer. But, like with SCs, there are different sizes of turbos and ways to control boost!

I say, re-post, and ask about opinions on all types of superchargers (including turbo) and see what people have to say.

Really, for an engine like yours which makes incredible low-end torque already, wouldn't a turbo be ideal? As you strengthen the engine, you could add more boost, but always have full launch control.

Adding a D series pro-charger is going to do exactly what you don't want it to do, give you an absolute monster, losing rubber every time you touch the gas, lol! God forbit you're ever stopped at a red light with a cop besides ya!

That being said, I love superchargers, but a 400+ci engine with a turbo is something special, you don't see that everyday! Give it a chance!

327???

Personally, I wouldn't run hypers on an engine that was boosted and meant anything to me. At the first sign of detonation you'd be buying a new set.

As far as S/C vs. turbo, IMHO, a turbo setup can be built cheaper and make more power. An mpt70 costs around $600, all you need from there is the headers and a wastegate. The materials to make a really nice set of headers could be bought for $100-200(log style).

I just can't justify the price of an S/C, that's why I'm building a turbo setup.

Sorry for going off on a tangent.

Sonix

iTrader: (1)

Confuzed - If you're still planning on the draw-through (as mentioned on the carb board?) make sure you drop your CR into the toilet. The largest dished forged pistons you can find in the 4.155 bore size.

junkcltr

iTrader: (1)

Please post the pistons you choose in the end. I looked for a while for 4.155" pistons with a 5.7" rod at a reasonable price but didn't come up with anything decent.

SpitotRs305

what about the LW2606F30 only $50 a piece
with press or floating wrist pins and a 16cc Dish

Sonix

iTrader: (1)

ONLY $50 a piece?? Damn man, that's $400 to outfit the engine! Speed pro forged 30cc 350 pistons are $200 a set... I guess that's a pricey size

I think you'd need at least 25cc's of dish though, to use a roots blower well.

Drac0nic

http://www.hangar18fabrication.com/blowthru.html

In regards to blower selection, I would definitely buy one that is a step or two up from your power goals. you never know how things will change to be honest, and besides that there's always the possibility you'll over shoot your goals.

Size the carb for good street performance on your engine, don't get wrapped up with huge CFMs in a blow through. You don't need it to perform, a 650 can make over 1200hp in a blow through application and your goals are a lot more modest. A lot of people don't bother with intercoolers in a blow through type setup, one of the advantages of it is that the fuel atomizing cools the air intake charge so it's not as necessecary as compared to an EFI setup.

Using the hypers should be fine, but be conservative on the tune up. In regards to the gapless rings, check www.turbobuick.com I thought some guys were running them there, but with mixed results. 9.3:1 isn't an optimal compression, but for a low boost setup it should be fine.

In regards to the fuel system, they're absolutely right don't cheap out on it, that's not the place to get in a budget crunch at.

On the whole turbo Vs. SC debate, my opinion is a blower is good if you don't have the facilities for a turbo kit, but if you can and are willing to fabricate stuff a turbo kit is more ecconomically viable depending on how you go about it. Don't forget the hidden stuff for each one, such as headers for the blower and waste gates for the turbo.

rhuarc31

I'd go with the ati intercooled setup you could run your current cam, or swap to a blower specific grind, either would work.

But as for your goals, I"d actually have to say they seem a little low. You shouldn't have too much trouble at least coming real close to 500 hp on just the motor with those heads and a good roller cam. I'd be looking for more like 600+. Think about it this way, 1.1-1.2 hp per cube is very doable for a streetable motor. With a 406 this gives you between 445 and 487 hp. Most blowers claim a 50% improvement, ATI claims up to 70%. If you split the difference of the hp numbers, a 40% gain would get you around 650 hp, or 400 hp and 50% would hit you right at 600.

Confuzed1

iTrader: (4)

Thanks all for the replies/advice. I had a thread going on over in the carb board about blow-thru vs draw through carbs while this one was still going. https://www.thirdgen.org/forums/carb...-vs-roots.html

I was OK with a draw through roots type blower until running a 4" cowl hood was mentioned, or cutting a hole in the hood even with a Weiand 142, which I may not reach my goal with anyway. Plus, I'd definitely need to lower static compression to at LEAST 8.5:1 or lower. I do believe with a 5.7 rodded 400 with a 4.165 bore, I'd need custom pi$tons or change to 76cc heads or something to lower that much. So-

Looking back to Vortec or a simular blow-thru setup again. I'm playing email tag with a guy from Pro-Systems to see if they can really build me a blow-thru carb that will require minimal tuning on my part.

I've considered turbos, and their efficiency wins hands down. And yes, I've seen setups that are pretty cheap, but require mods nonetheless. Some of those turbos can be had awfully cheap which could lead to reliability issues. But you're right, they can be sized for certain power levels. -And no "tangent" taken 327???.....
You have good points. I'll look closer at them, but adding heat won't help me with iron heads right?

Again guys, I'm going to have to tear the engine down regardless since I have rings in it that are not for boosted cars. I'll go forged when I put it back together.
-I currently run KB-147 hypers (-18cc dish) right now, and my static compression is 9.3:1 so -16 cc dish pistons aren't going to help me. I'm thinking I'll need like -22cc dish pistons to get my compression where it needs to be (8.5 - 9.0:1)...and I haven't found those yet. Or I need to get 76cc heads...

Sonix

iTrader: (1)

Alright, this has been bugging me on this board for a while now.
SIMULAR isn't a word. That has no meaning.
Similar is.

oh, .040" overbored 400.... Yea, that makes pistons a tad more rare
76cc heads are definitely a must, you don't have that now?!?

Procharger is the big player here in the blowthrough supercharger game, make sure to look at their stuff.

KB has a very wide selection of pistons, check the catalog on their website, it's pretty good as far as being able to navigate it.

Confuzed1

iTrader: (4)

You may be right, but SIMULAC is a brand! lol
Yep....and I only have 72cc chamber heads. And as I think more and more about it, I could most likely keep my compression with forged slugs, keep the boost down with a Procharger XXX series w/intercooler to get my goals of 450-500 streetable RWHP. Other option might be turbo, but I like the no brainer kits ATI has, and less heated intake air I'd think with the supercharger.....

BTW, ...... 690 bucks they want for a already modified for blow-thru carb!! I may be buying a wide band yet and tune'in my own carb!! I happen to also have a 650 cfm Speed Demon I can play with to see if I can mod my own carb for blow-thru.

camarokev400

keith black makes a set of 30cc dish pistons for a 400 i used to have them in mine i just swapped them out for the 16cc ones

Sonix

iTrader: (1)

Good call Kev. I just checked, those are hypers though.

However, they do make a 26.5cc, KB753
http://kb-silvolite.com/forged.php?a...tails&P_id=337
and a 23cc, KB9944
http://kb-silvolite.com/forged.php?a...tails&P_id=524

Both are forged, 400cid, 5.7 rod, and available in .040" overbore!

And would bring the CR to mid/high 8's with the current heads.

Confuzed1

iTrader: (4)

Hey thanks Sonix and camarokev400!! Yes, that's what I've been hunting for. I even have that site bookmarked and I didn't think of looking it up there..

-The -26.5cc pistons should drop me down to around 8.5:1, and the -23cc's should get me a tad below 9.1:1......I think either will work fine...

So my research has continued, and I've pretty much given up on the roots-type draw-thru setup because I'd rather not run a huge cowl hood or "outlaw" hood.

So - I'm down to Vortech (possibly S Trim) or ATI Procharger (D series). I did some searching and found that ATI seems to be the choice of the majority. However, I've only found good prices on Vortech blowers at Superchargersonline.com. I can get a V2 S trim kit for a dollar under 3K, or step up to a V7 YSi Trim kit for 3449.00.

But - for some reason, they don't sell Prochargers, not sure why. Still looking for the best price for a D series universal carb kit.

Either way, I won't actually buy either blower until my engine is back together so any warranty doesn't expire while I'm building. Still undecided whether I'll just drop the $$ for a blow-thru carb, or build my own.

Pulling the engine in the next couple of days, so I can start setting this thing up right for boost!

Sonix

iTrader: (1)

A few more thoughts;

Stock 400 block? Maybe consider a short fill?
Ask your machinist about the need for increased deck strength, ie strengthening the water ports on the deck surface. I've heard about doing this on 400 blocks, might be worth looking into.

Gap the rings WIDE. See KB's website writeup about it, and how even .080" gap negligibly increased oil consumption.

I think you should try modding it yourself, it doesn't exactly take machine shop capabilities, it's just a few modifications. Until 20+ psi boost, then you need to look more carefully at things.

stephennmm

iTrader: (1)

im doing a 414 stroker on the stock block trust me doing $400 is nothing in pistons i had to have mine made witch was 850 but thats besides the point dont let ever one tell you to go with 9ish to one compression yes it can work but its a bitch to get tuned and sometimes when its hot hard to get to run on pump gas witch is what we found out on my dads 355 with a 174 b@m roots blower and he had to mix fuel and if he got bad gas it detonated horribly but roots you would need the larger roots wiend blower for the 400 but 16268690270is a place called speedomotive call them and ask them about pistons they seemed to be really good on finding pistons i would say try to stay between 8 to 8.5:1 compreesion if staying carborated

Confuzed1

iTrader: (4)

Yes Sonix - it's a stock 400 block. I'm hoping I don't need to add fill to the block or anything else except maybe a re-hone to accept forged slugs. I had this block checked out and given a "clean bill of health" less than 5K miles ago. But still sound advice....I'll ask my machine shop if they think I need to anything additional to the block. BTW, the MOST boost I have planned for the engine is 12 pounds - AT THE MOST - not even gonna try 20+!! lol -That would put me in power levels that require splayed main caps etc. , and I won't waste my time or $$ doing that to a stock block. At those levels, I would tend to think a Little M or Motown block is in order...

And good call on the ring gaps! I've read it before, and it seems just the top compression ring needs the extra clearance. Looks like a .055" gap is the ticket, But I'll do what they recommend.

stephennmm - As much as I love the simplicity of a roots blower, I just can't find a small one that will give me enough meaningful boost on a 400. Only option I have is to get a 6-71 or 8-71.....which will have tons of power, looks cool at car shows, but will block my vision too much on the street. If I had an old Chevy P/U form the 50's or 60's with massive underhood clearance, I wouldn't hesitate putting a big huffer on it.

Guys, correct me if I'm wrong here but since I'm using a Vortec or ATI type blower, they recommend you don't drop your compression to the floor since at low rpm's there isn't much boost. That way you still have some power until you reach good boost in the midrange/high rpm's.

EDIT: I just got off the phone with a guy from Vortec, and he/they seem to feel I can get 450-500 RWHP with thier V2 S-Trim blower - without an intercooler no less! Said I don't need it since it's a carb setup and the charge will be cooled by the gas....Does that sound reasonable to you guys? I'm a bit skeptical, but they say it's no problem.

stephennmm

iTrader: (1)

a wiend street profile supercharger should push enough boost if you go with a smasller pully i think they are set at 6-8 with a stock pulley so a smaller pully would do it but the choice is yours on roots or centrifical but i know i personally like roots but good luck on either way you choose and post it if you find your pistons and try speedomotive like i posted cant hurt if you cant find them anywhere else

KS91Z28

Rumour has it they were selling the kits so cheap, they couldn't afford to help their customers when a problem came up, so ATI won't sell to them anymore.

If you're interested in an ATI kit, talk to HawksThirdgenParts --------->

Sonix

iTrader: (1)

That's somewhat true with that blower style, you don't need "super low" compression. Remember you only lose maybe 4% of power per POINT of compression, but you gain the ability to run LOADS more boost (which is worth a heck of a lot more than 4%).

Just remember the Buick GN, with a measly 3.8L engine in a heavy car ran a 7.8:1 CR or something like that. Not many people complain about lag or bottom end softness with those eh?

I'd still go as low as you can with the CR.

Yea, do look into a shortfill, it's pretty cheap and helps hold up the bottom end.

I'd definately want it intercooled, but that's just me. If you go down to 8.5:1 CR you can probably run 6psi of boost on 93 octane with the carb. Yea the fueling helps cool the intake charge (a bit), but it's not as uniform of a mixture, and that's worse with a carb vs FI. Usually high-tech FI (so no TBI, i'm talking real port injection) systems can run higher boost than carbed systems.

JPTINMAN70

Hey confused, I know that I am new here and have few posts, but I do have quite a bit of 400 SBC experience. If you are reluctant to do a short fill, at least go for a set of deck plugs for your block. Head studs are also a must with boost as there is little iron in the deck with those large siemesed bores. The short fill is more important in a high rpm 400, as the stock gm 400 blocks do not like to keep the bearings in place over 6500 rpms. A spayed cap conversion or at least a main girdle set up will help if you are looking to spin the motor. Just my 2 cents. Best of luck! JP

Sonix

iTrader: (1)

Can you explain this? I think I mentioned this above, but I want to be sure we're talking about the same thing. How does it work, and what is it supposed to do?

JPTINMAN70

Sonic,
The deck plugs are just 3/4" npt pipe plugs with a 1/4" or 5/16" hole drilled in the center. The plugs are installed in the six 3/4" coolant holes in your blocks deck surface.

You simply rough tap the coolant holes and locktight the plugs in place. If you are having you deck machined, leave the plugs slightly above the deck surface. The machining helps lock the plugs in place. If you are not having the deck done then leave them just blow the deck surface. Moroso makes these kits and I buy them on ebay for $10 to $15 all the time. If you can't find the Moroso parts any hardware store or supply house will carry these. You will just have to drill the holes.

These plugs are a must for any 400 that has high compression or boost. Also use head studs if you can. Make sure you have the steam holes drilled into your heads and head gaskets or you will create a dry deck which is difficult to deal with on the street. Many a 400 block is still alive due to the deck plug trick.

The short fill mentioned is also cheap insurance especially for a stock four bolt main block. The outer bolts actually weaken the bottom end at high rpm. These were truck and full size motors that would only turn 4200 RPMs in stock form. The filler is just a cement like product that has an expansion rate similar to the blocks cast iron. For the street you fill the bottom coolant passages to the bottom of the freeze plugs. This will substantially stiffen up the mains and keep the caps from moving around or "walking" as they say. The spayed cap option is really the way to go but with the required main bore machining you are going to spend a bunch of money.

If you have a two bolt block just use a main girdle which is available with the studs for around $80 on ebay.

If you keep your RPMs below 6500, the deck plugs and either the short fill (4 bolt main) or the main girdle (2 bolt main) should keep your 408 alive for a long time. You also shold use arp head and main studs if you can afford them.

I have a few older "400 trick " articles which I can scan if I can find them. Do a search for 400 sbc or 406 sbc and you can see what most others do to race prep these blocks. Best of Luck!
JP

Confuzed1

iTrader: (4)

Thanks once again for the replies everyone!

I’ve now officially made up my mind after much, much painful thinking, I’ve decided to keep it simple and go with a roots blower for the following reasons:
-I like the idea of massive low end grunt.
-I don’t plan to wind this engine over 5K normally, and 6K on rare occasions (like only if I’m losing- lol)
-I don’t need a blow-through carb, and tuning should be easier
-I might just be able to keep my AC too!

Also I discussed the centif. Vs roots issue to fellow gearhead I work with that has a garage full of modified AMC’s and old Vettes, and he was animate about going with a roots style – he said “if you really want power from idle to 5K, then there’s nothing better than a roots blower!” - He should know since he runs a AMX with a 6-71 on top of a 390. He’s also dealt with centrifugals and likes them too, but for everyday street use he felt roots was the ticket. If it was a strip car, he’d opt for centrifugal. By saying that, I realize myself that there’s quite a few guys that run centrif. on the street with no probs whatsoever.

So – roots it is. I don’t want to run anything as big as a 6-71 on my car, so I plan to see if I can run a Weiand 177 on it and try to make it fit under a 4” cowl or Jongbloed hood. How the heck I can find out if it’ll fit is beyond me, but I’m giving it a shot! According to Weiand’s literature, it should give me 7 lbs. of boost on a 400 at a 100% overdrive ratio using a 2.00:1 pulley. I could go to the highest pulley and get 12 lbs. too! -Of course, it’s just an estimate. I’m looking to drop compression to around 8:1 soon as I find pistons.

Confuzed1

iTrader: (4)

stephennmm - I ended up taking your advice...

I don't know if I'll meet my goal of 450-500 RWHP with a 177 or not, but I think it'll be close enough.
Glad you're here! I don't think I'll need any machine work, cylinders still have hone marks.

I never heard of "deck plugs" - I'll look into that. I have all ARP stuff, but no head studs, just bolts. But the mains have studs already.

Steam holes are there, and I run a 400 marine head gaskets (has the steam holes). 509 cast block, gotta look into the main girdle thing too, but I run a windage tray. I wouldn't pay to have splayed caps installed...I'd get a Motown block and forget about it. Great advice! Thx

Sonix

iTrader: (1)

This is an excellent thread, thanks JP for the info. A buddy of mine did that with his 400cid motor, but i'd never heard of it before. I guess it stiffens up the decks for high cyl pressure etc. (whereas 350's and other SBC's don't have this problem i'd guess?)

I'm going to look up the main girdle, i've heard of using that on olds 403 engines, but I can't picture what it is.

I thought that if using a fill (short or tall) you should have your bores re-honed to make sure they didn't close up a bit from the filler expanding.

Confuzed, I think you'll be quite happy with your plan. I wish I could drop by and see your car when it's buttoned up.

You can get the measurements of your current induction (ie. go to edelbrock and find out how tall the intake is, go to holley and find out how tall the carb is, etc), then get playdoh and see how close it is to the hood now. Then get the measurements from weiand for their 177, and do some math and see how much taller it'll be. Another way is to use some string across your front 1/4 panels, and see how far *down* the carb/air cleaner is now, then see how tall the 177 is, then with a bit of math figure out how much cowl you'll need. Cheaper than buying a hood to find out it doesn't fit

I'm not sure how feasible it is to lower the engine to make it fit...? Just throwing this out there as a possibility. Might require a custom k-member, or a motor plate though.

Since you're .040" over, (and 400's are notorious for not being able to take as much bore as say a 350), i'd highly recommend you look at a short fill. It's your call, and I don't want to "nag" you but it's so CHEAP, and would help keep the mains, and bottom of bores in place. No wiggles.

JPTINMAN70

Sonic,
Here is what is available on ebay now. These types of girdles are used on 302 fords quite often also. I will look for some more 400 sbc info and post it in this thread. They are my favorite motors.

http://motors.search.ebay.com/?from=...00+main+girdle

JP

Confuzed1

iTrader: (4)

Thanks Sonix, I hope I'll end up happy with my plan too!
I have the rough measurements of my prior induction, and it ended up being within an inch of hitting the bottom of the stock hood. How do I know that you say? Because I ran a 2" air filter element and attempted to run a 3" thick air filter element, and with the 3" I couldn't close the hood. -From the bottom/center of the intake to the top of the air cleaner measures 10 and 1/4 inches. (Measurement "B" on Weiand's website)

I also have the Weiand measurements of their 177 blower, and it *seems* like it *might* just fit under a stock hood - (measurement "B") is 10 and 15/16ths - that's minus the carb and air cleaner of course - in other words, the top of the blower itself with the carb adapter plate *should* fit under a stock hood. (or barely touch the underside of it.) So.....the size of the cowl *should* depend on the height of the carb plus air cleaner - in theory...

-Also Sonix, I'll look close at short filling the block before you nag me to death - just don't want any cooling probs on the street.

JP - I quoted a couple of your posts, and I'm living up to my screen name...confuzed
-So, let's say I use head studs, short fill the block and use the deck plugs..... do I still need to use the main girdle? I don't plan to spin the motor past 6K rpm really, because I shouldn't need to with a roots blower anyway right?

I just pulled the engine a few days ago, and it's on a stand waiting to get built for boost!

JPTINMAN70

Confused,
The bottom end stud girdle is not necessary, but will help at the extremes. I feel that if you short fill your block and use good fasteners, you should be fine. If you keep the RPMs down the bearings should stay at home.

I think that you are going to need some sticky tires and a good suspension to put all of that power down. You will not be disappointed with the 177 blower. Torque is what gets you moving and you will have LOTS!

The only other thing that I might sugest is to run some type of aftermarket oil cooler as the short fill reduces the volume of you cooling system. The 177 will add some heat also.

Best of Luck!
JP

Confuzed1

iTrader: (4)

Thx JP,
Yeah, good thought on the oil cooler - it certainly wouldn't hurt. I think my cooling system is up to the task. I just plan to add an aftermarket electric fan since the stock one is tired.

-How about everyone's take on Total Seal's Max Seal rings like these? http://www.jegs.com/webapp/wcs/store...50259_-1_10221
I'd opt for the normal tension oil rings though. I've read complaints while doing searches about excessive blowby on some roots blown motors and I think these might be a decent choice?

Sonix

iTrader: (1)

I was under the understanding that gapless rings are a no-no for forced induction setups. I think you want to be able to bleed off a bit of pressure, just in case.
Oh, are you doing any kind of crankcase vacuum or just a larger PCV system perhaps?

Confuzed1

iTrader: (4)

I see no benefit in bleeding off any pressure. It's just a waste of energy and it gets the oil dirty. Does nothing for the rings or cylinders.

Never heard gapless are a no-no.....these specifically say they are for boosted or nitrous applications. But as a previous poster on this thread says, I'll try looking at turbobuicks.com.....

shinobi-x

The 177 can produce big numbers. A member on the Chevelles.net forum has run 9.6x with a 177 in chevelle. Theres no reason you can't reach your goal with a 177. Im not impressed with 6-71's. Too big,front end is way to heavy,too much of an hassel if you ever wanted to drive you car in rain.

boa1277

I know you are sold on the roots style, but if you change your mind again this is where I purchased my Pro Charger D1SC setup for 3399.00 Make sure you call and talk to them for the good pricing.
http://superchargers4less.com/procharger/index.htm

Good Luck

Sonix

iTrader: (1)

Ya know, I didn't know why gap-less was a no-no, until I suggested it for a forced-induction build, and was universally corrected. Since I have no direct experience, I will take others word for it. ie, Mark has built a few forced induction builds in his time.

https://www.thirdgen.org/forums/powe...rbo-small.html

327???

My N/A 355 is a hassle in the rain, anything over 1/4 throttle is just a waste. I can't imagine a roots blown 400 in the rain.

shinobi-x

I sometimes drive my car in the rain. Not the ideal thing to do but sometimes I have to if my other car is broken. I won't drive it if I don't have to but when it has to be done,I can do it and not worry about getting to work.