1badrocZ

iTrader: (1)

Hey guys im playing around with the idea of going with a 406 bottom end from JRmotorsports and would like some opinions on my combo.
406 shortblock here
Im thinking about going with the 11.4 comp. flat top pistons with Brodix RR200cc 67cc combustion chambers which should make my comp. around 11.0 or high 10s. I havent decided on a cam that will work with this combination (if you have any suggestions let me know!) but i would like to use a holly stealth ram. Ill be using SD and tuning this myself (with the help of my brother) Do you see any mismatches or anything wrong with this combo? Will the heads work with this 406 and will the ports match on the heads and stealth ram? Ive done days and days of searching about this and have learned alot but i would like to see what you guys think first!

1badrocZ

iTrader: (1)

anyone?

grumpyvette

http://www.crower.com/misc/cam_spec/...00471&x=45&y=4

why not call crower and talk to them?

http://www.crower.com/misc/contact.shtml

this cam (above) works very well matched to an 11:1 cpr shortblock , in the 383-406 displacement range and a stealthram intake, but youll want to use 3.73:1 -4.11:1 rear gears and a 3000 rpm stall converter (auto) or (manual trans) to match it

maybe we can get someone to give you a DD-2000 estimate on the combo

1badrocZ

iTrader: (1)

Ill have a t-56 to match the cam, im just waiting to put it in. Do you recommend the brodix rr200, afr 195s or the trick flows 195cc with the HSR? I know the topic of which heads flow better has been covered many of times, all three seem to be fairly close but im not sure which heads match up to the HSR best?

grumpyvette

I think any of them will work but i think the port size on the TRICKFLOWS are the best match as to size/location in the ports in the heads/intake, the AFR 195cc is potentially the best flow rate but the differance can be made far smaller with minor port cleanup and the Brodix RR200cc are an excellent value also,and may be the best compromise

maybe we can get someone to give you a DD-2000 estimate on the combo with that 11:1 cpr 406 with that cam and the brodix heads

http://www.brodix.com/RaceRiteSmall%20Block.html

http://www.crower.com/misc/cam_spec/...00471&x=45&y=4

F-BIRD'88

Just have to watch your finished compression ratio.
A true 11:1 compression ratio is a little too high for 92-93 octane gas in every day use. (the real world). Will cause more tuning and reliability headaches than its worth.
An engine that detontes at WOT will soon loose its power edge. (ring seal) an engine that depends on computer/knock sensor invoked ignition retard to avoid detonation will not be all it can be in every day use.

You'd be better off aiming for a true 10 to 10.5:1 cr with proper .040" quench clearance.

You should measure the short blocks actual piston deck clearance @TDC and then calculate the true cr with a specific head and gasket. The block may requre dissassembly and deck milling to get a true .040" deck quench clearance including the gasket.

generally for a 406 you want a flat top (-7cc) piston with a "0 deck height"
using a .039" gasket and a 72-76cc head for a TRUE cr of 10:1 to 10.5:1.
This will let the EFI computer max out the timing for maximum power everday. Any more compression will just create problems and require tuning compromises or higher than 92-93 octane fuel.

popular dynamic compression thereoy is too simplified and does not account for real world in car air inlet and engine temperatures and cylinder pressure and cylinder to cylinder AFR variations in actual use. Not all the cylinder in a V8 engine run the same. you have to tune for the worst cylinder.

1badrocZ

iTrader: (1)

After a little more research i agree that the Trickflows match up the best with the HSR, both use the fel-pro 1205. I would like to keep the compression down in the 10.5 range in order to run premium pump gas, so i would have to go with the 72 cc heads and a .039 gasket. I would be interested to see some DD-2000 numbers but with the trickflows, 10.5 compression and the crower cam http://www.crower.com/misc/cam_spec/...00471&x=45&y=4

11sORbust

WHat is your source of information? I have tuned a few of my friends f-bodies with 12.5- 13:1 CR. They drive the em everywhere on 92 octane. There might be a 2-5% loss in peak HP, if any (according to dynamic compression and MANY other factors). The 12:1 engine with a sharp tune will kill the same setup at a lower CR w/ an aggressive tune, every single time. I'm running iron heads with 11.3:1 CR on pump gas. No detonation problems ever. MPFI is very flexible. It's all in the calibration though.

ljnowell

Why have to go through all of that for an extra 5% HP? Just keep the compression lower and make life easier.

11sORbust

I love the cam. Need some AFRs, they are the best. Low lift is where it's at. Max lift happens only once, while low lift occurs twice(in one combustion cycle). Get the heads bare, buy the matching springs for your cam and lighter valves. AFR seems to have heavy valvetrain parts. If you couldn't tell, I think high compression is better. 12:1 is a good place to shoot for. Actual compression ratio usually ends up less than calculated. You'll need 1-7/8" long tube headers FOR SURE. Minimum 3.5" single or two 3" dumps before the axle. You'll have a monster!!!




Put that advice in the bank, partner.

11sORbust

For a small bit of tuning it's worth it. Even though the tune is cut back, the higher CR motor still creates more force on the piston.

11sORbust

Remember, it's maybe 5%hp loss VS race gas.....not low compression.

F-BIRD'88

eventually your 13:1 compression ratio motor will self destruct from detonation on pump gas. Retarding the timing and running very rich jetting will reduce the actual power more than is gained from the extra compression ratio.
Over camming it to "bleed off cylinder pressure" results in a motor that doesn;t make the power it could with more modest compression and correct cam timing that makes full use of the induction and exhaust system without over scaveging, and sending potential power ( air and fuel)right out the exhaust. You end up with a compromised motor that does not make as much power as a proper designed "pump gas motor"
A motor that operates under detonation will very soon loose its edge and become a "worn motor" because the ring seal is destroyed by detonation. The rings and lands really take a beating. Many times you can't hear the detonation over exhaust noise. its going to be a short lived motor.

been there done that....

F-BIRD'88

"I'm running iron heads with 11.3:1 CR on pump gas."

"Actual compression ratio usually ends up less than calculated."

So the real actual compression ratio is....??????

11sORbust

Sorry to report it but all those engines have been running for years. I'm not talking out my A$$. MPFI makes the difference. That and all of Missouri gasoline grades have 10% Ethanol. Blended fuels change the stoichiometric A/F value (while lambada stays the same). You can get away with more compression AND timing with any alcohol additive.

WHen I CC my heads and deck, you'll be the first to know. WHat is your email address so you can get the updates?

1badrocZ

iTrader: (1)

I would like to kep my comp. around 10.5 to 11 for the simple fact that alot of money will be going into this motor and i would rather play it on the safe side. I dont have much experience tuning either so id like to keep it as simple as possible. I talked to a mechanic that builds race motors and he said 11.0 is the most he would go on 93 pump gas and alum. heads. For what im looking to build and achieve (450-500hp) i think 11.0 is plenty.
Whats with the BrodixRR200 heads. After searching i see very few people running them? They seem to flow as good as the afr195 and are a bit cheaper. I see that they require a 1206 gasket and the HSR is the 1205, is this a problem?

F-BIRD'88

"WHen I CC my heads and deck, you'll be the first to know. WHat is your email address so you can get the updates?"

Well you do that. When you find out that your 11.3:1 motor is not even near that, let me know.
In the mean time, you're not doing anyone any favours( especially a novice that wants to do it right the first time)
Advising them to run such high compression but haveing to resort to "fuel dumping" (rich mixture) and retarded timing to keep it alive on 93....You're not further ahead, power wise and reliability will be less.
Up here in Cold Country, we have Sunoco Ultra 94 that is minimum 10% Ethanol
At 10%, Ethanol only leans the AFR mixture slightly.
Most of North America has Ethanol enhanced gas available.
A gasoline tested at 93 octane average is 93 octane reguardless of wether it has ethanol in it or some other method of getting the octane performance.

LilJayV10

iTrader: (5)

I used the 288XR hydraulic roller cam in my 406 and am very pleased with it. the car had a 2800 ACT 9.5 convertor and 3.23 gears, it would pull non stop to 6200, and thats with the second ring installed wrong, that dumbazz mistake. I have protopline 220cc heads w/ 2.05 1.60 valves and 64cc chambers. I had the block 0 decked, and am using KB 147 pistons, which have a 18cc or 22cc dish, can't remember right now, with a .039 felpro racing gasket my comression ratio is right at 10:1.

I agree, 11:1 is kinda high for the street, but with aluminum heads it's do able with good tuning, I think LT1 guys do it a lot. I would keep the compression around 10:1 just to be safe, the additional power you could make wouldn't be worth the risk, pain, or tuning it, but thats just me. But I am running a carb and not EFI.

The car was as streetable as my stock 305 TBI.

I am putting the enging back together this week and putting it in the car. I have a few weeks off before I start my new job, so thats what I will be doing.

oh, the car ran 7.8's @90.5 mph in the 1/8 on 255/50/16 radial tires in a t top car with no SFC's or LCA's. With the rings installed correctly and sticky tires and some minor suspension work, the car should have went mid-low 7's easy and would have been 100% streetable on pump gas.

11sORbust

I never said to run rich. Where did I say that?????????? The engines I was talking about runs more on the lean side.

I have a 406Ci SBC, flat top pistons, 64cc heads and .042 head gasket. The pistons are .010 from the deck. Not even near that, huh? You do the math then.

Ethanol doesn't ACTUALLY lean out the mixture, it changes stoichiometric.

I gave my source of info, broad experience. What is yours?

11sORbust

10.5-11.0 CR is a great place to be. Brodix heads have bigger shaped ports if they require 1206s. That means decreased velocity, given similar port volume to AFRs. THere is more to heads than flow numbers. Try reading a book on pressure wave tuning. The Steathram is not suppose to be opened up to a 1206. I think you'll end up with too little of a sealing surface on the intake(roof)-head area. Contact Holley for more info...

Please don't think I was suggesting 13:1. Others are taking my word and running with it.

F-BIRD'88

36 years of hands on experience. I'm old enough to remember what real gasoline was. Sunoco 260 And sunoco 280 leaded premium .essentually race gas at the pump.
I've built and run varoius high compression ratio motors and helped tune friends stuff. Even experimented with the same short block with different cr's and configurations.
About 36 years total real world experience on what works in a every day environment.
A good undersstanding of engineneering, physics, math, and the limitations fo the real world,


And definatly what $$$$does not work.$$$$ Got the broken parts to prove it.

When you get into the marine engine environment when the motor operates at WOT for much more than few seconds at a time you really see the realistic limitations.

A bud of mine learned that hard lesson on two nice off- shore motors that had just a little too much compression ratio (10.74:1)

just a note: An engine that operates at WOT at a stoichiometric AFR ( reguardless of the fuel used) will not last long or make maximum power.
needs extra fuel to cool the combustion chamber and burn all the oxygen at WOT. Othe wise the combustion chamber will over heat and damage the motor.

Do you know the AFR that you have to run your motor at to keep it out of detonation. Probably much richer than it needs to be Richer than 12:1. This extra fuel keeps you safe but reduces power. as compared to if you had a little less cr and a AFR between 12.5 and 13.3:1

Onless you can afford to build a lot of motors to replace all the broken ones its just not practical to run exessive compression in daily useage. All the tuning and tweeking and fiddling nesseessary to keep from damaging the motor is just not worth it.
if you ant to run a high compression ratio motor buy the correct fuel for it. If you don't want to spend the $$$ on the correct fuel build less compression into your plans.
A motor with 11:1 to 11.5:1 will need a 98 to 104octane fuel. Thats the real world, welcome to it.

11sORbust

I DONT RUN THE ENGINES RICH!!!I really don't care if you believe me or not. I gave my advice to the original author, not you. It's really quite sad that you decide to focus on my post instead of giving your opinion to 1badrocz. Now the focus is shifted from him to us. You might feel comfortable hyjacking threads but I don't like it. The mature thing to do would be to start a new thread to debate CR vs octane.

Your experience alone does not mean I'm wrong. If you had an open mind I would have explained why these cars run on 92 octane. It's not that complicated. Oh well, time to head back to the real world.

F-BIRD'88

"It's not that complicated."

That's right, You have to run a less than optimum tuneup to make it survive. ( less than max power air fuel ratio{wether computer controled or carbed}, less than optimum max power ignition timing.)
The engine will live , but will make less power. One mistake and $$$$kaboom$$$.....
You and I are not the only ones that have tried this.
I ran a 12.65:1 motor with all the tricks ( tight quench, polished chambers yad yada yada) and never once heard any detonation on 94 octane. ran pretty good.

ran much,much better on 110octane gas and max power timing. thou. even sounded better.
Till one day the inevidable/unrelelenting laws of physics caught up to me.
One day while heading to the track I forgot to turn back the timing from optimum 36deg to a safe 28-30 to get by on 94 pump gas till I got to the track and switched to 110 for racing. ( dual fuel system)

forgot all about it. Went to pass a car and all hell broke loose. Never heard detonation. But broke a ring land and cracked a cylinder wall and destroyed a cylinder head just the same.
this same 350 short block ran for 10 years in two of my cars and 1 of a buds with other heads, cams intakes and compression ratios up to 10.4:1 and configurations, even NOS. Till this event killed it.
One combination at 10.4:1 it was very touchy on 94 and pinged bad on 93 during testing unless the timing was retarded. Performance was noticably slower with the retarded timing. Ran same engine at 10.03:1... no detonation, not sensitive to ignition timing, ran consistantly faster et and mph. much better overall.
Just one example of the real world.

It is hard to recognize the sound of power robbing detonation in a WOT running motor till you're right up beside it at 100mph in a boat. Does not ping or rattle. ( thats severe detonation with priignition) just sounds off. If you keep at it the engine will self destruct shortly.
run the same engine with less compression or higher octane fuel and it smooths right out. No more stress and strain. Goes faster too.

11sORbust

Thanks for sharing your experience. It seems like your high compression motor would of lived forever if you didn't mess it up...

I understand what you are saying. There is just more to the picture than what you have seen. How about this, 13:1 CR and a 200 dry shot of N2O on 92 octane? Most people say that's impossible. I know for a fact that it's not. It didn't run as fast compared to race gas but it was DOable.

Ya know, before dismissing my posts may you should have tried to understand. Everybody is capable of learning something new, even if it conflicts with experience. I'm not wrong in anything I said...

ljnowell

I dont know man, this one makes me wonder.

1badrocZ

iTrader: (1)

Not to get off topic guys but what is the small base circle cams that alot of people are running? Is that crower cam listed above a small base circle and are there any other good hyd. roller cams that will work with this setup. BTW ive decided to go with the AFR195 heads and probably the 74 cc to keep my compression down to low 10s. I ran a DD-2000 and the numbers impressed me...peak hp 525@6000rpms and 511 tq@5000 rpms with 10.5 comp. and small tube headers w/ mufflers. Perhaps a slighty larger cam would help a bit? Anybody have any other cam suggestions so i can plug them into DD-2000? Man i cant wait to get this project going

F-BIRD'88

Most all of the cam companies can supply a small base circle cam. Special order. Crane has a series of Powermax (off the shelf) Hyd rollers that have small base circles. check out their web site.
you still have to check and verify rod to cam clearance even with a small base circle. Don't assume anything. check for your self.