Pablo

iTrader: (1)

this months Chevy High performance has a dyno test of the motor combo I thought would kick *** , Victor Jr, Vortec heads, Lt4 Hot cam and your run of the mill bottom end (9.7:1 cr?)
422 Hp!!! Is that not insane! We could all build one of these what with how cheap the parts are. THey mentioned it had about 14" of vacuum at idle and hey thats plenty, my 305 has about 14" of vacuum at idle and Ive gotten it to run well with some tuning

Just thought I should share some substantiating evidence to support my hp hypothesis. I know what im building next (If i ever get to stay in one place for any decent amount of time that is)

Semper Fi
Pablo

82resto

For real? Did they do extensive work with the heads, or just mill them to yield 58cc and bolt them on?
I thought an LT4 hotcam was too large, and took away nearly all the vacuum... oh well

Jon

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89 GTA
Beautiful Gunmetal gray, LB9 305 and T5 tranny. Only 60,000 miles!
Dual cats, 3"flomaster
Accel 300+ Ignition, wires, cap, coil, etc
Airfoil
KN Airfilter
Removed Screens on MAF
SLP 1 3/4 headers
No Smog/AIR system

Tas

I try to tell people to use single plane but people still want to put the piece of crap carb performer under their TBI.

------------------
-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

NTChrist

I'm pretty sure that those numbers are for a 350. In other words, there was no milling needed.

------------------
No guts, no glory.

DM91RS

3.08

JPrevost

So I should do a cam swap (have lifters already), get my heads worked for the LT4 lift, and slap on a single plane intake.

I was going to do a cam swap soon anyways. Probably spring break if I have the money. I'll do a roller cam and we'll see what that does with the lower lift but faster ramp speed. Hopefully that's enough to get ~40 hp.
Pablo, all I gotta say is DO IT. Get a 350 and be VERY very happy.

------------------
, Jon (350 TBI!)
91 Red My website

DM91RS

JP the HOT cam has to be one of the best priced rollers for the HP there is. Hope you do it. I may or may not use that cam depending on what things are like when I rebuild my 350, but I would like something more agressive than the LT4 that I used the 1st time.

[This message has been edited by DM91RS (edited September 30, 2001).]

firbird

is that fast burn heads that they used because, i have heard some people say vortec heads instead of fastburn because they have the same mest up style, just maken sure because thats good hp its maken

RyanSS

Ever since I read that, I have been planning on using fastburn heads, a hot cam, a single plane intake, a 454 TB, and Hooker SC shorties. Then I bought desktop Dyno2000. That's where the trouble started. The best I can get out of it is 432HP@5000RPM and 479TQ@4500RPM I was hoping for at least 450HP with the Fastburn heads. I mean why spend the extra money for fastburn's when they only add 10HP over the vortec's?
Am I missing something here?
I also tried the hotcam with Aluminum Canfield 195's(more flow than fastburn's with bigger valves and same price) and I got within a couple HP of the fastburn's.
After that, I decided to try a different cam. With the Fastburn's I used a TPIS grind with .520" lift and 226 duration the combo made 453HP@5000RPM and 484TQ@4000RPM. The same cam with the canfield's only made about 420HP. I don't really want to go with a cam bigger than the one from TPIS due to the car being a daily driver with no lower than 3.42's and I want good gas mileage and idle vacuum. I guess I'll never be satisfied.

Oh, how can I find out the Lobe center angle and intake centerline of a cam?

Anybody have any ideas?

------------------
89 RS parts car
Daily driver 91 RS auto LO3 70k, 14x3 K&N Open element, cat-back delete.
Coming soon: 350, headers, loudmouth exhaust.

Pablo

iTrader: (1)

Thats because fast burn heads suck, they flow less than vortecs (also a "fastburn" style head but not so named) up till about .4 lift i believe. I think the fastburns only start outflowing the vortecs at real high lifts and imho i dont think it justifies the price at all considering they have 30 more cc's of intake volume to flow BARELY more than vortecs. Pathetic i say, someone slept in class the day they talked about bernoulli's principle

btw the test is with vortec heads

firbird

thats cool pablo thanks pablo thanks for clearing up that for me and i have to say thats one good setup there, need to get a cam swap soon

Tas

SDPC has vortec heads that take high lift cams for $600 www.sdpc2000.com

------------------
-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz



Got Beach?

JPrevost

Vortec rocks. Fastburns are good if you have extra money burning (pun intended) a hole in your pocket.
Pablo, when do you think you'll ever through something like this together?

------------------
, Jon (350 TBI!)
91 Red My website

fast_broker

iTrader: (1)

Pablo is right about the Vortec vs FastBurns. Higher lift the Fast's are better BUT if you use big springs in the Vortecs, you WILL need to upgrade to screw-in studs or the OEM pressed ones will pull out sooner or later. also, the Vortecs can only take about .470"-.480" of lift before valve cap intereference with the seals, and the Hot Cam is .492"/.492" with 1.5 rockers... I am going to use the Hot cam with both heads sooner or later, so I'll let you guys know what I get. RPM Air Gap, though. Single plane later, I guess I could try. 'Later' is a key word for me, if you've paid any attention to the stock market, you'll know what I am going through...

EDIT: And, yes, a single plane is fine for 400hp+ engine (although RPM will make 400, too, quite easily) and probably req'd for any 450+hp engine. I must admit, a tall single plane (like Holley Strip Dominator) does look about as cool as it gets and is probably tuneable/drivable with our TBI PROM knowledge)

[This message has been edited by fast_broker (edited October 01, 2001).]

[This message has been edited by fast_broker (edited October 01, 2001).]

brharris27370

Anybody heard anything about the Edelbrock E-Tec 200 series heads. Vortec style that is suppose to out flow fastburns by 20hp worth. Same price as fastburn heads.

I would like to know what they did to the vortec heads. I mean the 350HO crate puts out 330hp with vortec heads. Surely they didn't gain 100hp with Cam and intake alone.

[This message has been edited by brharris27370 (edited October 01, 2001).]

firbird

thats what i am thinking now how can it give me 90 hp over my engine now that produces 330hp and the cam maybe can do 40 but i dont think milling the heads and putting the single plain intake one over the preformer intake will produce another 50 hp to = 420hp am i missing something??????

JPrevost

I would just like to point out that the 330hp engine WILL make 50 more hp and 25 more ft-lbs with JUST a cam swap.
http://www.sallee-chevrolet.com/Chev...er_Deluxe.html
Go ahead and look at the parts they used. Yeah, basically it's an RPM intake, same carb, still flat tap and makes 380hp!!
I don't really like that cam but it did make the hp number no doubt. Probably isn't EFI friendly.

------------------
, Jon (350 TBI!)
91 Red My website

fast_broker

iTrader: (1)

That is a VERY common combo right now, ie Comp XE268 w/Vortec heads. The cam is the Comp Extreme Energy XE268 with 224/230 duration (Sallee has the wrong duration for the intake, at 244deg!!!) and is probably Comps BEST PERFORMING and BEST SELLING flat tappet cam for street/street racer cars. The vortec heads will work lift-wise but I bet they have screw-in studs and guideplates because I believe those ProForm rockers are non-self aligning and the Comp springs will pull out pressed-in studs sooner or later. The rollers are good for about 15 free hp vs stamped rockers, BTW. I believe those valve part numbers are OEM Vortec, but not sure, could be better ones?

I have build several similar motors but only achieved 374-375hp consistency. Close enough, I guess. I am quite sure that I have used that cam in more carbed street-car motors in the last few years than all others combined. It just "works"... BEst "new" design Comp came out with...

That cam will NOT work with EFI very well, 110LS. For a carb, it is nice in a 350cid with a small converter and is a GREAT cam... Pulls VERY hard from about 2500+ through almost 6000 with moderately lopy idle...

An RPM/Air Gap can make 400+hp all day long, BTW, and should offer better throttle response in most conditoins than a single-plane. Not bashing the single planes, but, as I always say, if the motor is in a daily driver, use the dual plane. Ever see the runners on an RPM manifold??? They are quite large. The limiting factor in the intake system becomes the Vortec head intake ports, trust me. (besides the puny valves and 170cc intake runners, but can't count those for budget buildup)

EDIT: Bring that CR up to 9.6:1 with pistons and you get 400hp, BTW. I suppoe you could mill the heads and use a thin gasket instead of pistions, too... BUT, remember, that crank is not a steel crank like the ZZ4's and doesn't like 5000+ rpm extended at all!!! ie, use ZZ4 shortblock for more compression, steel crank. Same block, PM rods anyway...


[This message has been edited by fast_broker (edited October 03, 2001).]

Brent

iTrader: (1)

Hmmm, I just ran that Sallee engine through DesktopDyno. It made 7 more HP and more avg torque using the Hot Cam .

Even more interesting is how Hot Rod's engine makes more 32HP(dual plane)and more torque under 3000rpms than Sallee's engine, using less duration.

Torgue @ 2600rpms, Sallee = 319, HR = 358

fast_broker

iTrader: (1)

The Hot Cam is a roller and an unfair comparison. The Hot Cam is surely a better cam for the Vortec heads, or for any head, really, because of the very fast ramp speed (ie similar potential for airflow between cams even with smaller duration because the valves open VERY fast and close VERY fast with a roller, ie more area under the curve than similar duration flat-tappet) and 112 LSep... Also, the smaller durations of the Hot Cam (218/228deg) helps to give more lower-end torque, as you suggested(?), without sacrificing top-end. The Sallee engine's XE268 durations are 224/230deg at .050" tappet lift, a bit more than the Hot Cam.

That is my TBI goal, BTW, to get 400hp with Hot cam. It can be done. It WILL be done, as soon as I can borrow a Diacom or get Craig MOates to support 1227747 ECU...



[This message has been edited by fast_broker (edited October 03, 2001).]

fast_broker

iTrader: (1)

Pablo, did they run the KIT 1.6 roller rockers with the Hot Cam or use some 1.5'ers??? the 1.6 ratio rockers would mean .525" lift and that means some pretty heavy machine work on Vortec heads. even the .492" lift with 1.5's is a lot. ie, not CHEAP, unfortunately.

If you guys have never tried a Hot Cam in a well built/thought-out 350, you are missing quite a treat. (ie, big intake, headers, nice carb, nice HEI advance curve, 2500 stall converter, 3.73/4.11 gears)

DM91RS

I've got the article in front of me and I can't see any mention of any rockers at all. So I guess they are using the ones that came with the Vortec heads. They do mention $100 for head work; larger spring pockets, shortening valve guides and drilling and tapping for screw-in studs. That sounds like a lot of work for $100. I've got a set of Vortec's setting here that I would like to get done for $100! Or is that the going rate? I have not priced these mods.

fast_broker

iTrader: (1)

100 bucks if you know someone pretty well or have been to a shop a few times. Otherwise, buck-fiddy-200 or so.


While we are on the subject, you have all heard of the FastBurn 385, right? ie, 385hp, Fastburn heads, 1.5 stamped rockers, ZZ4 cam/pistons??? I put 1.6 Roller rockers on the intake and 1.5 rollers on the exhaust and got 412hp and 398lb-ft, w/carb/AirGap. I bet that the mildly worked-over Vortecs in the shop will produce 390-400hp on the same shortblock. That's a LOT of hp with a LITTLE cam. with either heads... TBI to be motors...

See:

"finalizing TBI motor-to-be" here in TBI down a bit for more details.

Those Vortec heads are really nice for the street. Especially good if you can use 1.25" dia springs (ie, no spring pad machining) and cams with .480" or less lift (no stem seal tower machining) but you still gotta get screwed-in studs, which you really could do yourself if you put down the beer... The OEM springs that come with them ABSOLUTELY MUST BE REPLACED, too. A cost not talked of much here. 80lb of seat presure just aint gonna cut the mustard.

[This message has been edited by fast_broker (edited October 03, 2001).]

Motopsyco

1 question guys on the Lt4 hotcam, will it work with the stock computer on my 91 tbi firebird

-Stormr

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"If its in my way-It gets run over"

--'91 firebird
305 TBI
Hypertech chip-thermomaster
Edelbrock performer intake
Crane compucam 2031
B&M shift kit
straight pipe exhaust-with Flowtech resonator tips
160 thermostat
open element

Pablo

iTrader: (1)

The computer isnt the problem, its the chip


Yep fast, they machined the heads to accept the cam and 1.6 rockers as far as I remember, Machined down the seal towers and pads I believe


When will i get around to doing this? I dont know. I dont know where Ill be a month from now much less know whether ill be able to drive my car next, i joined the marines and next thing i know they are sending me to all kinds of places, go figure. They dont give much notice either (all the navy guys in my class allready got their orders we still have no clue and wont for awhile)

Tas

Hey Pablo, my friends brother that went to the marines a bit before you already got shipped to the gulf. "Parts Unknown" as he wrote in a letter to his mom. Good luck to the both of you in these times.

DM91RS

?Sorry guys.......got my signals crossed on this one when reading some old posts....just ignore

91RedFirebird

I got the hot cam in a 350 with 190cc heads, and woah its a big jump from the lo3 and me being retarded Its my first time tuning EFI and I still don't have it down right. and to get that kinda power you going to need some good exhaust to go with it. the Eldelcrap headers and 3inch flowmaster system was just too small. Right now I'm fighting with hooker long tubes and a sphon t-56 crossmember. But even with the bad exhaust and my crappy tune I was able to eat up most cars a came across. Big block injectors are a must and I would say go with a single plane, the motor really wakes up around 3k.

91RedFirebird

With the ELB, the exhaust and if I can learn to drive I think I can hit high 12's on street tires.

GOY

Single plane or dual plane....... no EGR makes it not even worth a second glance to some of us.....

But for what it's worth - dual plane is the way to go unless you are running a crazy combination.

91RedFirebird

With EFI signle planes aren't as prone to lose down low torque as with a carb who's fueling is purely based on vaccum. Other than Rock crawling trucks no one races under 3k where most dual planes out shine single planes. I will gladly trade off some unusable tire destroying torque for a more up top.

flaming-ford

iTrader: (7)

i dunno fast is kool but, i like destroying tires way more than i'd ever want go super quick. Then again my minor buildup should have a most of my low torque left with a good bit more top torque!

GOY

You're not saying anything new, but I still don't buy it for an Idle (850RPM)->6000RPM redline engine. The fuel metering may not be DIRECTLY affected by vaccum (MAP???), but the intake charge speed GREATLY suffers, which will DIRECTLY affect power production for most intake speeds below 4000 RPM in an engine under 400 cubic inches. I base that on the VAF = (CI/1728) x (RPM/2) x VE, formula.

A 305, operating at 4000 RPM, with an assumed 80% VE at 1 atmospheric pressure, is still consuming under 300 CFM total - much less than the manifold is capable of flowing - killing air speed. Consider the size of that plenum...... even at 6000 RPM, we are talking about 423 CFM.


Consider the size of that plenum......

Fast355

iTrader: (2)

Which is why, I don't understand the decision to switch to a single plane. I am back to running a Bored to 2" GM intake on mine. Plenty of flow for a 305, even up to 6,000+ RPM with MUCH improved off-idle and mid-range torque. I took the Bored 3704 off for my 383. I am still running the 454 TBI though.

That is one of the big myths to TBI, that the intake and TBI are greatly holding back a stock engine. Bore the intake to 2" openings, slap a 454 TBI on it and you can make 275 RWHP @ 5,500 with the ability to rev to 6,000 RPM and still only build about 1.5 in/hg of vacuum underneath. A manifold designed for TBI is better for air fuel distribution than a carb intake with a TBI adapter is. The front cylinders tend to get more fuel and the rears less. Don't believe me, take and put pyrometers in each header tube. I have and the rears run alot hotter=LEANER.

GOY

Wow, this is the second time in 2 or 3 days that F355 and I agree about something....
.... don't go thinking that like means that I like you or anything now F355

91RedFirebird

CHP did dino test with the vitor Jr and a GPP dual plain and the single plain on gave up 10 torque at like 3400-3800 and had more torque and hp at lower rpms where they started the test at 2600 and got an extr 10 hp in the uper end. And the TBI intake is almost the same as any other sbc aluminum carb intake from the 80's other than the tbi mounting pad and the circles under the injectors. Same old 2 runners make a t and then head into the Plenum. That T is a restiction and yeah any other aftermarket intake would make more power over the whole RPM range. I have never head of a TBI running rich in the front, most of the time its in the rear due to how the throtle blades open. Was that on a stock intake of one of the spacers where the TBI is mounted forward?

Fast355

iTrader: (2)

That was a performer RPM with a Projection adapter on it. The rear cylinders ran lean @ WOT.

91RedFirebird

yeah that one is not centered, it does have a dual patern where the tbi can be mounted in the front or the rear but never the center.

Pablo

iTrader: (1)

goodness this is back from the dead

we have hashed this out many times

GOY

You probably havent been here for awhile.

First off, the example people like to pull about x displacement engine pulling x amount of airflow is thoroughly misused.

Lets say that infact your example applies to any engine we are talking about (which it shouldnt, otherwise that would be a very weak 305)
Your point about it consuming 300 cfm of air ignores the fact that manifolds and intakes dont have CFM ratings without pulling any vacuum.

For example, a 600 CFM carburetor flows 600 cFM with 1.5" hg pressure drop. If you saw 1.5" hg in a street car you are severely choking the engine

Back when I had a 305 TBI with a 310, ported heads, large cam, torker II single plane, and stock TB, I would regularly see 1.5" hg by 6000 rpm. The problem would clearly be worse with a dual plane.

Lack of Vacuum signal is the bane of the big manifold/carburetor combination, not runner lengths, plenum size, etc. While those do play an imporant part in creating a decent vacuum signal, that is just a requirement of a carburetor, not an FI system. If fuel could be introduced regardless of vacuum signal these things would not have as much of an effect as most people tend to think on the resonance tuning of the intake manifold and filling of the cylinders.

Consider that the LT1 Intake manifold has extremely short runners, if im not mistaken they are shorter than a victor JR's runners, and it has a larger plenum. Why then was it put on a car that generated pretty good low end torque and high end hp?

I have actually tried both, my firebird was setup to run either TBI or carburetor and i could swap in 20 minutes or less, the ecm always controled my dist, i burned my own chips and monitored afr with a wideband and datalogging.

The TBI was far and away superior in low end performance and I really did alot of carb tuning, far more than most people would probably do. The lack of vacuum signal really reeked havoc with the carb. I never did get to try out a double pumper that I purchased but the fact that I needed so much volume and duration for my pump shot on the carb speaks for itself.

If you search for more posts on this subject youll find this has been talked about over and over and over and over again and enough people have proven this nonsense wrong about single planes not capable of low end power that this stuff should be put to rest.

Fast355

iTrader: (2)

Yeah, I have run single plane, Performer RPM, bored edelbrock 3704, and a bored stock GM intake on my 305 with a 454 TBI on top. The single plane sucked for low-speed torque, even when it was where I thought it was adequately tuned. With a vehicle weighing 5,300 lbs and towing 4,000+ at times, I can definately tell when I lose 30 ft/lbs on the bottem. By-far the best intake for a 305 TBI, in my experience has been either the stock GM piece that was bored or a bored edelbrock 3704, combined with a 454 TBI.

GOY

Pablo -

The LT1 produces decent low end power due to the small camshaft, not the intake. I actually currently own a LT1 vehicle - if you do, start it and put it in drive with your foot on the brake. Let me know how that pulse feels. That's the infoulable LT1 intake showing it's weakness. Swap the camshaft, and all of a sudden that "Low end" torque seems to disappear like a fart in the wind. If the intake was capable of maintaining low end torque, this wouldn't be the case.... it's the cam in the engine, not the intake that promotes a 2400-2700 RPM torque peak. The intake simply makes up for the cams weakness torwards 4500RPM by the "Ease of access" to large volumes of air despite short valve timing.

Also, you take into NO account, what so ever, that the same "Factors" that create a good operating enviroment in a carb application will be required for a TBI application - fuel still has to flow through those runners. If air speed suffers, fuel will drop out, period! Secondly, you will have very poor overall filling. Air is slowed at lower engine speeds by larger, straight runners, no debate to be had.

If you feel comfortable in saying a single plane is great for TBI applications with proper tuning, that's fine. Common sense, and knowing fuel has to flow through those runners won't allow me too agree.