Moparts Tech Archive
Big Block
Blowers or Blown Info
Roots blower guys, let's see your combos!DusterDave
Moparts Member
Posts: 3531
From: Tampa, FL
Registered: Mar 2000
posted 08-25-2002 05:56 PM
I'm interested in the whole combination, including rear gear ratio and converter stall speed if you run an automatic. What cam specs, carb size, brand and case size of blower, static compression ratio, piston brand, etc.
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chrisf
Moparts Member
Posts: 1727
From: British Columbia, Canada
Registered: Nov 1999
posted 08-25-2002 07:09 PM
since nobody else is helping you out dave i will. Once you go a forced induction you wont want to go back to NA.
my engine in my challenger is a 68 383, bored .030 7.5-1 Venoila's. stock e heads,comp soild (.540-.562 246-252@.050) w/ 1.5 crame rockers.
2 750 carters, 2" hooker headers, Hampton 6-71 w/ 5% overdrive (13-14lbs boost)
5200 rpm Island Converter, 4.56 dana.
i shift at 6000rpm and go through the lights at 6800rpm. 10.52@130mph, car weighs 3605 w/ me in it.
i street drive it and had it out yesterday.
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DusterDave
Moparts Member
Posts: 3531
From: Tampa, FL
Registered: Mar 2000
posted 08-25-2002 07:50 PM
That's more gear and converter than I thought you had. The reason why I started this thread, is because I have an insurance settlement coming one of these days, and I always wanted to build a blower motor. I want to see and learn combos that work well for street/strip applications.
This is what I was considering:
477 CID
MP Megablock, 4.500 bore
Keep my factory steel 3.75 stroke crank, E-heads, Eagle rods, and Pro Parts headers
Port the exhaust ports
Scott Brown custom hydraulic roller cam
7.5:1 comp.
BDS 8-71 kit with hard anodized interior and 8mm drive, 10-12 lbs. boost
Pair of 1050HP Dominators (since I already have one)
I figure this engine will make a ton of low and midrange power, so I thought of changing out to a 3.73 or 4.10 gear set and tightening up the converter to around 3,600-3,800 rpm. Your thoughts?
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-25-2002 08:34 PM
Blowers can allow you to load the motor at much lower stalls, for a street driven car I wouldn't have a converter much beyond whatever your cruise RPM is at 60MPH. Too much stall with a blower can be detrimental 'cause it hits/slings the tranny with more inertia and can at best easily unload your tires or at worst break something in the drivetrain. On a 470 inch motor the way I'd set it up you'd have approx 650lb/ft below 3000rpm and the motor would pull past 7000.
Think more street oriented, believe me, keep it relatively mild you'll enjoy it and want to drive it more. I've built several Supercharged motors in the past 20 years with great success. Blowers build A LOT of Heat and too large a blower won't be as efficient once it heats up.
A drag only car, go bigger.
With that in mind, your combo looks pretty good, I'd use the long 7.100" eagle and put 75% of your port work into the Exhausts. On the street, I prefer smaller blowers turning faster than I do bigger ones turning slower, you don't really have enough motor in mind to fully utilize an 8-71 IMO, unless you're primarily going for image. Dual dominators are gonna be overkill with the E-heads (your exhaust is going to be your HP limiter) unless they're 750-850CFM. If it were mine I'd talk to Robert Landy @ DLI and run Their 250 Powercharger. I ran a smaller 174 powercharger on my same 12.30/111 shortblock
only with 906's and a .020" thicker head gasket. Never had it to the strip in that configuration (I couldn't keep a clutch or tires on it long enough!!)but it was silly quick. I drove it to the Mopar Nats in 1989 or '90 that way, about 1200 miles R-T.
Chris looks like he's got a great combo for a 383, but I'll bet his exhaust port is holding it back a little bit, a 440+ is gonna need more than a stock E-head port or the boost is gonna start backing up and heating up the blower at around 5000.
I'm thinking about prototyping an intercooler and boost by-pass for the Roots , I've had a design sketched out for several years. Now that there's so many people building I/C cores and tubing, I'm gettingthe Jones to whip one up.
My Daily Driver is a traction limited mid 13 sec. 2000 Si that is supercharged and runs 11 psi and still gets 31MPG. The unit is an eaton that spins 1.44 times the crank ans the motor routinely sees 8200RPM. With slicks and a limited slip unit it would go easy 12.80's. 255hp @ the crank from 1.6 litres is pretty d@mn good in my book. The one advantage to messing with these little imports is that it keeps me in touch with the latest technology, I'm died in the wool MoPar, but I also loved messing with Kaws, Suzukis and my old mid 11 sec. V-max. My dabbling with imports is more an extension of my enthusiasm for sport bikes that make viscious power.
If I can help you set it up, lemme know!
Wize
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chrisf
Moparts Member
Posts: 1727
From: British Columbia, Canada
Registered: Nov 1999
posted 08-25-2002 08:49 PM
Wize.
this is my first blower motor and am slowly learning. what would you sugest then to fix the exhaust problem?? i know the cam is tiny and have been planning on changing it this winter to something around .600" lift
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-25-2002 08:57 PM
Chris,
Does your blower boost increase on the big end? E-mail me some specifics on your Cam timing LDA/Phasing etc. What are your 60 foots? I need some other Specifics such as header tubing size & length.
I'll do some math, I've got some grind info I'll try to retrieve that might help you out. I think a 383-400 makes a great app for a blower.
Wize
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DRAM
Moparts Member
Posts: 4806
From: West Palm Bch. Fl.
Registered: Jun 2000
posted 08-25-2002 09:08 PM
Dave, i think wize has pretty much echoed what we already talked about on a couple issues. the 1050's for example (too much carb) and the heads neeing work on the exhaust mainly. i like the combo other than those items. i don't have a problem with the rod length at all though. i know if you think that duster runs good now, just wait... incidentally, i do like the idea of the gear change and a lower stall than what your currently using. the pure torque of that combo in a light car like yours will have no problem at all. your next investment will be some stickier tires LOL...
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DusterDave
Moparts Member
Posts: 3531
From: Tampa, FL
Registered: Mar 2000
posted 08-25-2002 09:16 PM
Thanks for the advice, Wize and DRAM. Lot's of good info to chew on. Well, I have a friend that wants to buy the Dominator. So, maybe a pair of Holley 850's instead. Do you think I should sell the Edelbrock heads and step up to 440-1's for the better breathing? Or keep the Eddies and max port the exhausts?
[This message has been edited by DusterDave (edited 08-25-2002).]
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4x4 440
Moparts Member
Posts: 1082
From: Glenmoore,PA,US
Registered: Jun 2001
posted 08-25-2002 10:38 PM
I am building a blown Hemi engine but only have the block right now. My buildup is Hemi mega block with 4.35" bore/4.15" stroke ported cast iron dual plug heads, 7.5 or 8:1 Aries pistons, BDS 871 blower with bird catcher electronic fuel injection. I am looking for 1000 Hp through a 4 speed and a Dana rear. I have wanted to build a blower engine since I was 15 and now at 39 I said what the f***. This will take a couple of years and about $30,000 for the engine but it is only money. Good luck with your project. Chris.
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gtxmonte
Moparts Member
Posts: 1892
From: Trinity, AL. USA
Registered: Oct 2000
posted 08-25-2002 11:49 PM
I am going to be the naysayer here. Obviously you like performance and want the car to be relatively quick while still streetable. My thoughts are, why handicap a potential high HP combo with E heads. Unload those things and put a head under the blower that will let it make some stones. While 440-1s would normaly not be my choice for a mild motor, in your case with forced induction they will be fine. That lung on top will push plenty of air through those big ports, so low speed port velocity will not be a concern. Some mildly worked -1s with INDYs blower manifold would be the ticket.
Monte Smith
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smokindatires
Moparts Member
Posts: 684
From: Valdosta,Georgia
Registered: Jan 2002
posted 08-25-2002 11:58 PM
Dave, got to thinking. Why dont you just put a 250 shot nitrous system on it? You wouldnt have to change any of your existing parts and it would be cheaper than the blower as well. I know the visual image of a blower is cool,but as far as power goes I'd really look into a nitrous setup. Its cheaper, lighter weight, only provides power when you need it and can be used with the existing parts that you have. Not to mention, I bet you'd be more consistent with a nitrous system over a blower. As the blower heats up the air intake charge, you slow down. I know that with a properly sized blower, it wont heat up the air all the much. I've built several different combinations using Desktop Dyno and then ran them in the same car on Desktop Drag 2000. The nitrous engine was faster every time. Not sure if this is what you wanted to hear, but just giving my .02.
Rob
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Keith W
Moparts Member
Posts: 2860
From: Greenville Sc
Registered: Nov 1999
posted 08-26-2002 12:00 AM
An old neighbor from TN just built his Blower Motor for his B bod. He put a standard 440 steel crank together. BDS 8-71, 2 750 mechanical Holleys on the top. He used a custom Isky blower cam. Venolia 7.5:1's. He had a set of Indy Steel heads and just used them for now.He bought a GER?? 2,500 converter with the 727 and 3.55 street gears in the Dana. He just got back from 10 chassis dyno pulls . The final pull made 700 HP and 750 Lb Tq roughly. I can get details from his buildup later.I forget what pullies he ended up with but it was 13 lbs of boost.
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blowncuda
Moparts Member
Posts: 2757
From: Fairfield,CA
Registered: Nov 1999
posted 08-26-2002 02:35 AM
Well you know my thoughts. I have built a few blown engines myself. I pretty much echo what Monte said. Get some heads use the big blower and put some carb to it...I went 9'0s on a big blower mildly ported dual dominator car and drove it all the time...But what do I know..
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DusterDave
Moparts Member
Posts: 3531
From: Tampa, FL
Registered: Mar 2000
posted 08-26-2002 07:24 AM
blowncuda, what heads did you use? I knew the Edelbrocks would be a bottleneck in the whole combination. But, keep in mind that I definitely want to keep my 2" Pro Parts headers. So, if I keep raising the power level like switching to better heads, the 2" headers become a restriction.
Let me put it this way. I want to run 10 flat through the mufflers. Can I do it and keep the Edelbrocks?
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-26-2002 07:46 AM
Monte and B-C make some good points, and if price is no object a set of -1 Indys will make more power and with the boost on demand, have no low-end laziness. I guess my point is with a well set up supercharger combo, even with the E-heads you already have, you're going to make more power than your possibly going to need, if you can't launch 700, 800 isn't going to do you much good. Your 2" pro parts will be fine, to fit Indys might be more $$$. DD's coming into some money but another $2500-3000 for all the peripherals would be hard for me to justify on top of the $$$ for the Blower.
Blowers to me are like razor tuned hot street motors (like you have)that run a full time 125-250 shot of Nitrous, with enhanced sound effects!! If you go overboard with cam port and carb, it's more difficult to tune because the only way to compensate for rough low end (yes it is possible cause when your cruisin the motor is under vaccuum)is more boost and then your crusin in high gear at 45, you stomp it and instant tire smoke with (no forward motion) is what you get. Blowers make it too easy to write checks your suspension won't cash. As I said in the previous post, bigger blower/higher boost, the more heat=less air density=reduced blower adiabatic efficiency. Once a non I/C blower heats up it's very slow to cool back down, and when it's hot your pumping serious heat into the motor which means high octane full time. Look at an Adiabatic chart comparing inlet air temp to outlet temp under boost, you'll see what I mean. Dave your in FLA, something to think about. Tuning is the key to making a blown motor happy, Detonation will be virtually undetectable from the seat with a Roots, so make sure whoever you consult knows what he's doing.
Build the block strong then tune the combo (Cam timing/carb)on the mild side and you'll still have all the power you want and run on pump gas; When you go to the track, add your slicks, change to a smaller snout pulley dump in some 110 octane and have at it. Best of both worlds, I think you'd be happier.
Wize
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Blowfish
Moparts Member
Posts: 490
From: Falconer NY, USA
Registered: May 2002
posted 08-26-2002 10:29 AM
When I started building mine , I talked quite a bit with Blowncuda. The only thing I didn't do was choose a cam he wanted me to.
I've got a .030 440 with a BDS 8-71. Dual Holley 830's, steel crank, align bored and honed, Manley rods, Pro-Gram main caps, SRP pistons, Aerohead 452's. I had to open up the chambers to lower compression a little. My final compression is right around 8.67:1. Yes ,it's high ,but it's what I have ended up with after porting and adding a copper shim. Did a little bit of port work on the exhaust side. Flowing into Hooker Super Comps. 2" primaries into 3 1/2 collectors, coated by Jet- Hot(what an experience).
I choose a Crane Powermax dual pattern. .336/.504 .352/.528. Ray Bartons shop told me that this "should be fine for a street driver. It is similiar to the old Direct Conn. Super Commando cam. Good choice." Also, the guys at Hot Heads said that I shouldn't have too many problems seeing how I was NY with the cooler air.
I have a 4.56 rear gear inside the Phord 9 in. along with a 31 spline Auburn locker. The trans will be a 727 with Kevlar and bolt in sprag and a 3500 stall anti-balooning conv.
With exhaust running through either Flows or Dyno max Ultra flows, Desk top dyno says I should be running 10.23 at around 3200lbs. But I'm not sure of the weight yet.
Okay guys. What do you see that I have done wrong?????
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-26-2002 10:48 AM
I think you'll have a great running combo. IMO the 8-71 as I said before is overkill but you can't beat it for curb appeal.
You are going to be really suprised how mellow that cam is going to sound with a blower, I think I would have run the Hughes 244/249 @.050 cut on 112's with that much stall. With that cam and gear you don't need more than 2600-2800.
As it is, providing you can hook, I think you could run 10.70's @ 126 with about 10 pounds of boost. The compressed air's gonna run out of places to go above ~5000 rpm so your boost in the manifold will rise but the power will stop going up. It will run great but I don't think you have enough cam and head to get 10.30's.
6.5 lbs of intercooled air can make more power than ~10psi of non-intercooled, The blower is a heat-sink, keep it cool and running under vaccuum 80% of the time and your motor will make better power when you stomp it.
I like higher static 8:-8.5:1 on most of my street combos.
Wize
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DRAM
Moparts Member
Posts: 4806
From: West Palm Bch. Fl.
Registered: Jun 2000
posted 08-26-2002 11:08 AM
i've only built 50 or so blower combo's but only a couple of those were mild street combo's. the rest were all top alky mills. it just seems that there's a lot of good info spread around here and no one (including myself) has asked the magic question yet. Dave, how much streetable power are you looking for? is 750 HP enough?
i still think you can make the eddy's work if some porting is done, unless of course you want something crazy like 1000 HP. then maybe it's time to start looking at some race heads. with forced induction everything changes as far as cams, carbs, etc.etc. some of the folks posting on this one might be better suited than i am to offer advice. i'm not really used to dealing with such small blowers and mild combo's.
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-26-2002 11:34 AM
DD
I think we can get right at 10 flat with the eddy's , Chris's motor is making about 700 at the crank and net about 615 to the wheels, that's one 383 you don't want to mess with! I've got to hear back from chris on the info I requested and review Fast68 and others data on the exhaust port.
I think the cam converter 60 foot is where we gotta make the move to get high nines; I don't want to bet the farm on the exhauust alone. With an intercooler like I have devised, we could really move!
Wize
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blowncuda
Moparts Member
Posts: 2757
From: Fairfield,CA
Registered: Nov 1999
posted 08-26-2002 12:38 PM
To run the number you want,low 10's it is pretty much a no brainer combo for your car. Add boost...Its true big huffers are not very efficient. My partner and I's race car was originally a baby blower motor. It was equipped with a 177 Wieand supercharger,the car wieghed 3600 lbs and went 10.20's,so there is no doubt they can be made to run the number as well .I have built a few baby blower engines and they work great,heck the centrifigals are very stout pieces as well and are hands down more efficient. And they can be made to run killer HP numbers with a carb as well in a blow through set up. Just look at Filipowski's car running in T/A. his car is a blow though that runs 8.70's on a Drag radial at 3400lbs..
I got the impression you were looking for as much of a visual statement as ultimate performance. The 8/71 and twin Dominators will get that,and can run the number you are after as well. There are obviously many ways to skin a cat. I have never been into the all out race blower deals that they run in Alcohol and Fuel classes. I have put together some real fast street type set ups,couple that run low 8's in cars that are driven regularly. I am not an engineer so dont ask for me for theories. I will leave that to the engineers. I do know that to obtain the goal you want it does not take alot of effort,a few dollars but not alot of trick stuff.
I ran 9.0's in the Cuda with a set of IRON heads. They were a left over set of Zeeker heads from my at the time race car. Basically a 440-1 in iron. They had minimal work done,just a good valve job and some minor exhaust work and bowl clean up.
Like anything else it is a total combination that makes a package run the numbner. Not making needed changes(gear convertor etc)are just compromises that have to be overcome.
BTW the intercooler idea is a very good one..Been a problem with the roots set ups all along. I would like to see what Wize has to address that issue. BDS offers one but most avoid it for a couple of reasons. One is that it is just too tall. And of course cost. I would rather have 10 lbs of good quality boost that 15lbs of poor boost. But what is a roots guy to do,there are not many alternatives. There is of course one very good one..NITROUS...Nothing like an intercooler in a bottle
Not looking to piss in anyone's Cheerios here just sharing my experiences and thoughts. The exchange of info like this can only be a good thing in my opinion..
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lleuth
New Member
Posts: 96
From: Tampa,Floida
Registered: May 2001
posted 08-26-2002 04:30 PM
What does fuel atomization look like comming out of an intercooled roots setup? The centrifugal guys like me are cooling air only and the carb atomizes as it's supposed to. Any idea of the effect of that type of setup? Just courious
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-26-2002 04:55 PM
lleuth,
My system would run the air/fuel past the fins of a fluid cooler similar to an A/C system. It would route a chilled water/surfactant solution to a resevoir and an electric water pump. The trick is to have enough efficiency/residence time to cool the compressed air befor it enters the manifold. Cooling baffles (if properly designed) won't cause the fuel to drop out of suspension as the area above and below the intercooler will remain pressurised. There will be a pressure drop across the I/C but that can be compensated for by increasing the developed boost to achieve the desired net boost.
There are a couple obstacles, namely if the ambient inlet air is too cold the potential for frost or condensed water to build up is at least possible if insufficient heated air passes through the system. Another is the limited time the system can recirculate adequately chilled fluid, heat is constantly added to the process faster than it can practically be drawn away so eventually the fluid heats up and needs to be repleniished. Of course if a small refrigerent compressor system were belt or even blower pulley driven, this would not be a problem. The A/C compressor would not have to be very large and could possibly be driven off one of the rotors from an extended shaft/coupling on the back of the blower.
On a wet carbureted system you won't be able to keep the fuel in suspension if passed through an intercooler, aditionally the friction losses would be horrendous. Couple that to the fact you would be pumping a hot flamable mixture around the engine compartment and you see that design is not practical. It works perfectly well in a direct port injected system because only air is moving from the compressor through the intercooler.
Blower cases could also be designed with surface cooling jackets either seperate or in series with the fluid intercooler as described above. The science and technology is well understood, even practical if you consider the potential efficiency gains. It's just who would fund the development?
Oh well, back in the box I go!
Wize
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chrisf
Moparts Member
Posts: 1727
From: British Columbia, Canada
Registered: Nov 1999
posted 08-26-2002 05:15 PM
Wize
i lost my cam card but am looking for it. i will email you asap. the funny thing about my motor is it's 100% street drivable and well behaved, runs well, cools well and it's a riot to drive
thanks for the offer
chris
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DusterDave
Moparts Member
Posts: 3531
From: Tampa, FL
Registered: Mar 2000
posted 08-26-2002 06:18 PM
Good. I can hit 10 oh's and still keep my Pro Parts headers and Edelbrock heads. It'll be too much of an expense to switch to Indy's at this stage of the game. And, although not very efficient, I can get away with using a pair of 1050 Dominators. Sounds great, except some of you are making me a little concerned about the "hot blower" issue. I never drive my Duster for more than 30 miles at a stretch, and its usually during the evening hours. Would it still be a problem?
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-26-2002 06:57 PM
DD,
Not a major problem, it's just to point out that they do build up heat, (BTW + O/T, Alcohol & blowers are SWEET combos cause they don't heat up, even under squeeze)For the Street I'd rather run a 6-71 25% over and 8.25:1 than an 8-71 1:1 with 7.5:1 for better street manners and stronger overall torque. Besides you're at sea level which means mondo power when boosting!
In fact for what you're doing, there's not much point in going with a 470, 19 cubes aren't worth the expense and with the right blower set-up, you'll never miss them, we'll make them up with RPM on the big-end. But if you're going Mega block you get the 4.50" bore anyway, oh well more room for valves!
The pro parts primaries are little longer (length)than you need for a blown motor but won't hurt ET much. There's no real practical way to shorten them due to where the slip ons join-up.
I checked and Dwayne is getting 240-ish out of the exhaust port, I'd be tempted to run a slightly larger 1.84-ish exhaust valve. 240 will get us there with the right cam with HP to spare.
When you get ready, if you want we'll talk to Scott about a Hydraulic roller that'll pull to about 6800. How tall are your tires on that beast, btw? Need to calc trap speed/gearing. I've got a 7600RPM solid grind that works VERY WELL but the spring pressure's a little rad for a streeter. IMO Phasing and lobe shape is every bit as much the key to Blower grinds as the grind itself.
Wize
BTW, Chris's motor in your ~400lb lighter car would probably get pretty close, 10-teens maybe.
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DusterDave
Moparts Member
Posts: 3531
From: Tampa, FL
Registered: Mar 2000
posted 08-26-2002 07:50 PM
Wize, yeah I would definitely want to get the exhaust ports opened up. A bigger exhaust valve is another possibility. The only reason I chose an 8-71 is because that's what BDS has listed in their blower kits for an RB motor. Since I'm a novice at this stuff, I'd prefer to buy a complete kit instead of having to piece it together.
BTW, my rear tires are 32.5" tall.
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-27-2002 02:09 AM
Dave,
Talk to Robert over at DLI about a whipping you up a 420 (approx the same displacement as the 6-71 GMC case) Powercharger/440 kit, The B&M, (now Holley) blower design is a little more efficient IMO than some of the comparable 6 and 8-71's, you could even do it with the smaller 250 blower. I don't think there'll be any problem at all hitting your goal. I'd run a big single 1250 dominator as I think what you have in mind (2100 cfm's of dual doms) might be a little tough to modulate between a street tire and slick set-up, layin' down a good short time is going to be the key to knocking on the 9's. Have Dwayne do a full tilt job on the exhaust port, once we get the port profile we'll work out the cam specs.
It'd be tough for me to resist the temptation to "Supersize"- do a 2 stage plate/direct port N20 (intercooler on the BONUS PLAN)system, especially if you do a megablock!
Wize
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Streetwize
Moparts Member
Posts: 1425
From: Charlotte,NC USA
Registered: Dec 2000
posted 08-27-2002 02:34 AM
I decided to print out the E-mail between Chris and I regarding his blower tune, hopefully it may be of some related interest to the group:
-----------------------------------------
----- Original Message -----
From: Jetstream.net
To: streetwize@carolina.rr.com
Sent: Tuesday, August 27, 2002 12:11 PM
Subject: moparts/blower
"Does your blower boost increase on the big end? E-mail me some specifics on your Cam timing LDA/Phasing etc. What are your 60 foots? I need some other Specifics such as header tubing size & length"
HI Wize.
It's chris fryer here (chrisf)
and just responding to your thread on moparts about my cam.
I should add I wasnt sure what to buy when I did it and didnt have the experts at moparts to help me out so I called the comp tech line. They asked all the info and then recomended a cam. which turned out to be later the smallest solid sbc blower cam they make.
the specs are w/ 1.5 rockers .540-.562 246-252@.050 lsa is 112 degrees
I am unsure about my boost beacuase I kinda look straight ahead while I am running the car and not looking at gauges. I would say I do build some serious top end mph though,
I ran a car 2 weeks ago were I ran 10.55@130 and he ran 10.60@125 so I do know my car has great mph.
my 60' times footbraking at about 1800rpm are 1.46-1.49. I am still working on the 4 link and gtx monte has given me some tips
I am not sure about the header tubing length they are hooker super comp 2" I run through 3 1/2 " race bullets as well (ya through the mufflers!!!)
what else do you need to know??
thanks for your help
Chris
Chris,
Your performance is very impressive, no doubt! You seem to have excellent drivability and your 60' are right there to where it would be tough to improve much. As for changing the cam, you might gain another tenth or two by adding another 10 degrees and .030-,040" lift to the cam, something like the Hughes 5663 solid cut on the same 112 centerline, you have enough stall to use it but IMO it's probably not worth all the hassle for very little overall gain. A better plan would be to work your E-heads to flow about 295i/-245e
which again means just some bowl work on the intakes and a good Stage 3 full port on the exhaust. You can try using 1.6 rockers on your exhaust first, it might help slightly by giving you about 3-4 more degrees and .030 net lift at the valve but IMO the port can't move enough air. The rough calc at your race weight is 616 to the wheels net, so you're approaching 700HP at the crank!
As for watching the gauges, let's keep your eyes on the road! lol. I'd recommend rigging a cam-corder securely in the car and the lens focused on your gauges, on your launch count off out loud "1-2-3-4-5-6-7-8-9-10", to give us a real-time "synch" so I can see your shift points and watch the boost. If you can cleanly focus the camera on the gauges as well as the tree/traps of course we wont need the "verbal". If your boost rises in a roots blower (especially at higher RPMs in high gear) it's a good indication that the air has no place to go and it's backing up/building pressure in the manifold. This means you either need more port or more cam. We know getting air "In" is not the problem. A simple calc says the exhaust porting is going to be your best bang for the buck, we can do the cam but again, we might have to re-examine the whole fuel curve, lets not throw out what's already a very good combination. The porting should increase your mph/top end charge and all else being equal, LOWER your boost in the manifold, which means MORE boost is making it in to the Cylinders. Worst case we may need to jet-up the carbs a little bit.
Hope this helps,
Bobby/Wize
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