I have the option of taking my heads and dual plane intake to a shop to have them looked at for a porting job. I have a wiend stealth intake and Holley Systemax II heads. Would it be worth my time to have the heads and intake cleaned up? I run nitrous (150hp shot) and i have a 9.6 to 1 compression ratio. i have a XE 274 cam it has .519 intake lift and .523 exhaust i believe. I may upgrade to a 393 or 408 in a few years (have 2 girls so dispossible cash is at a low right now have to save for future motor mods). My other option is just going and having my combo tuned on a dyno. It has never been really tuned and certainly never in a dyno. or should i do both.
2 Port or not 2 Port
- Thread starter 86bluecobra
- Start date
bluevenom867
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I woulds say have them look at the heads,but as for the manifold....
I would do a Victor Jr. sense your spraying,and a 1" open space beneath the nitrous plate also,to get some more plenum volume.
I would do a Victor Jr. sense your spraying,and a 1" open space beneath the nitrous plate also,to get some more plenum volume.
i have always thought about putting a victor jr on it but i only race twice maybe 3 times a year and i don't know if i want to sacrifice the low end torque for a bit faster at the track 3 times a year. i mean 3500rpm on the street starts to turn heads. my 351w is a little louder then your everyday 5.0L.
bluevenom867
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86bluecobra said:
The dual plane isnt superior in torque nessicarily.
With the Fords,the equal (well,better,niether is equal on all 8) runner lengths help alot.And your manifold probably doesnt have enough plenum aera now for your motor.
Trust me,we had a simlar combo at one time (with a C4) and it was fine on the street.You dont even notice "low end" torque cause you get up to 6800rpm really fast
bluevenom867
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86bluecobra said:
No.
Get your self a jet kit and go to the track and jet it up (pri and sec) 2 jets and see if you mph picks up.If it does keep increasing jets untill it does,once it drops of go back to the jets that gave you that last increase and your tuning is basicly done (pretty much,nitrous is a little harder).
Ill send you a page on tuning for the nitrous.
bluevenom867
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To be honest, you have a very sound combination and it would benefit from some dyno tuning. Most people don't realize that there is usually 20-50 horses and ft/lbs of torque available right there. Especially with a tuner that can really get the full throttle advance curve, part throttle advance and every circuit in the carb dialed in well. It could very well act like a wholly different motor once the tuning is done. There are also some other minor tweaks such as picking just the right ignition components and making sure the exhaust is exactly what you need. With a motor that stout it would really benefit from a set of 1 3/4" long tubes such as is available from MAC Performance.
bluevenom867
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I will agree with the long tubes,they help.
But he already has an exhaust system and really,shorties aret that bad (at least if there a 1 3/4" also).
But as for tuning,just watch your track mph and read the plugs.
Is the carb you got now mech. or vac. secondary?
But he already has an exhaust system and really,shorties aret that bad (at least if there a 1 3/4" also).
But as for tuning,just watch your track mph and read the plugs.
Is the carb you got now mech. or vac. secondary?
There's actually quite a bit to be gained beyond simple mile per hour change when tuning a set up. Such as improved part throttle launch control, improved reliability, cleaner shifting characteristics through improved RPM control that a proper tune can do for a car that an enthusiast at a track could spend years or more trying to accomplish, much less learn to do when that knowledge isn't extensive or tested. As far as proper exhaust scavenging goes, I know for a fact that luminaries such as David Vizard have found anywhere from 10-50 horses just with proper exhaust tuning. It's a very valid way to gain a monumental amount of power and can equal the amount of power gained by stroking a motor.
Here's a link to a couple articles detailing some of Vizard's discoveries surrounding exhaust tuning: http://www.geocities.com/motorcity/track/6992/vizard.html
Here's a link to a couple articles detailing some of Vizard's discoveries surrounding exhaust tuning: http://www.geocities.com/motorcity/track/6992/vizard.html
bluevenom867 said:
thumper460
Founding Member
11.56 as it is now... rocks!! With the stealth and heads worked.. you will realize enough add'l power to drop that 11.50 to an easy 11.20 or even an 11.10 !! with a good tune... Damn, the wind isnt the only thing FAST in Canada!! I would think your sitting on a high 10 sec car!! I have run the stealth intake ported to the heads and a 200 shot of juice with NO problems!! the Vic jr. did loose just a little lower end... but nothing that wasnt made up on the top end!! have fun!!
Just me....................................
Thumper
Just me....................................
Thumper
bluevenom867
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hrspwrjunkie said:
Eh,its barley readable
.Tuning on a carb for max hp (wide open) is that easy,you get the fastest mph and the plugs still look good.The other circuits dont need much tuning,other than a couple of screws turned to make the baseline set-up Holley gives you run smooth.
Yea,I have read a bunch of differant exhaust articles,but the thing is,is every set-up is differant.
You can dyno two headers with the same lenght tube,same diameter,some collecter size,but still get differant numbers...why?Cause small stuff,differant bends,collecter entrance angle,collector length,blended weld,and even the material.
Now theroy can some times be differant than what actualy works,but basicly...short,fat tubes are for high rpm,and long small tubes are for low rpm.I think most of the shorty headers problems is the they have a terrable collecter angle,tight bends,and the over all length of the collector is bad.
But all this "knowledge" doesnt mean a thing is you dont got the cash to spend on parts,so us it with what will make you the most power.
thx thumber and my carb has mechanical secondaries. i have a msd distributor and a digital 6 msd ignition box aswell as there blaster 2 coil. i don't think my shorties are 1 3/4 i believe they are bbk 1 5/16. i guess ill remove my heads and intake and get it ported. btw would my dual plane intake like a 1 inch spacer?
bluevenom867
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86bluecobra said:
I would say yea.
See,when you move the carb up,your giving the plenum more volume,but with a dual plane,your also letting the cylinder thats opening be able to draw more form the carb,cause normaly the one cylinder can only draw from half the carb (one secondary and one primary).
Also,make sure to put the spacer UNDER your nitrous plate.
ok will do i'm going to vancouver on friday maybe i will pick up a 1 inch spacer. btw thx for the link. i have never done any spark plug checks after i have done a run. i didnt know how to. i will pick up a jetting set and do that aswell. might be worth my while to get a wide band air fuel gauge set up aswell. wife not going to be happy me spending a bit of cash.
bluevenom867
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86bluecobra said:
Go read up on that sight how to make your self a nitrous fuel system flow tool.That way you can set the flowing fuel pressure.And if your runing your plate off the same reg. as your carb,that should be done befor any other work,as you would see a nice (i.e. larger) gain by tuning your nitrous
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