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My head choice dilema...
So we had a discussion about heads...GT-40's and 40Ps. I had narrowed down my choices between these two. I got a couple of replies for TW heads.
The Edelbrocks and cast iron varieties seem to be the heads of choice with AOD owners. The TW w/5 speeds. I had originally thought the P's would help me retain some low end so that my car didn't feel so sluggish out on the streets. The smaller valves created more velocity down low and it would help me retain torque. I looked at the numbers and the Edelbrocks flow about the same as P's up to about .3 lift. After this, it's all Edelbrock. The TW out flow both all over the board, but have larger valves. I don't want a race engine, but a nice running 5-liter with plenty of pull and some good HP (Say...320+ HP). The setup will be: .030 over block Cobra intake Mild cam (depending on head choice) ***Heads of choice*** 24 lb injectors 190-lph fuel pump 76 m mass air 65 mm TB 3.27 rear Off road exhaust, 2 chamber flows AOD w/ Transgo shift kit All in a full weight 91 GT. I want the car to be streetable, reliable and, again, not be sluggish down under. That is why I decided on the P's. The Edelbrocks flow the same amount of air on the intake(total from .1 to .5 lift), but are 40 lbs lighter and flow more exhaust! I don't have the cash or time to re-do this combo twice. I need to get it right the first time. You have steered me right before, and I trust your judgement. I have done so much reading and studying that it's driving me mad. I need to hear more experiences... ------------------ Robert 91GT; 88 ASC McLaren #709 |
are you planning on replacing your headers w/ "p" only headers?
i would go w/ the edelbrocks. You can find them used for the price of new "p" heads. ------------------ 4.10's,long tubes & 75 shot...Goes 12.50's Check it out at http://www.burnouts.stangnet.com 11's coming soon!!!! Heads,intake and cam are all here |
I agree with NOS_Notch. Go with the Edelbrocks, I'm happy with my set, and don't let the number games fool you. They flow well enough out of the box, and even better with only a SMALL amount of touch ups. And you can use you're existing headers, etc. with them.
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I have the TFS TW with a E-303 cam, and I have more power than the tires can handle at 2500rpm and above. There is tons of lowend.
Sky ------------------ -1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, headers and 3chamber flows. 12.55@107mph 50-175 Nitrous Works WET Kit just added. |
Get the edelbrocks, you wont be disapointed. Excellent quality, light weight, and exactly what your looking for.
------------------ 1993 GT/AOD '93 Mustang GT |
Go with the T/W heads, they flow the most at low lifts (E-Cam) than the Edelbrocks. I run the Edelbrocks and if I had to buy another set of heads I would buy the Victor JR's or a set of the T/W.
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The edelbrocks are mediocre heads.....they flow around 235-240/175-180. IMO waste of money when you can get a set of TFS TW's for $1000 that flow 250-255/190-195. Edelbrocks are overpriced too.
------------------ Dustin Saleenized 89 GT,428 rwhp,TFS Street Heat Intake,TFS TW Heads,TFS #2 cam,BD-11A 9 psi,FRPP 1.6 rr's,BBK 70mm TB,Pro-M 75mm Bullet,MSD 6BTM, FMS 9mm wires,BBK longtubes,BBK Short H-pipe,American Thunder cat back,3.55's 12.3@119 |
afr 165 kick *** ...especially at the low lift on a mild motor!
------------------ 88LX notch, Speedpro EFI Procharged! |
You will make plenty of torque with the TFS heads. Mine are ported, along with a heavily ported GT-40 lower. (Fel-pro 1262) On the dyno I was making about 275 lbs of torque by 2800 rpm. 310 lbs by 3400.
Thing is you have to buy good rocker arms and 6.700 inch hardened pushrods. You should get this stuff with any head though. ------------------ 1988 Mustang GT 12.0 @ 122 1992 BadAzz Wrangler 1993 Explorer |
If you are trying to decide amongst all heads, the TFS Twisted Wedge are an easy choice. A steep flow curve, along with small combustion chambers, great flow rates, and a killer price on a set of aluminum heads.
The TFS heads will blast the GT-40 series out of the water. Edelbrock makes quality heads, but the old myths around the Twisted Wedge taking out valve guides is finally coming to a fizzle. Lot's of people run them with NO problems. So here's what you are left with. Great flow velocity and huge numbers with a quality name brand head for hundreds cheaper than the competition. That's what the Twisted Wedges deliever. |
So everyone agrees on the TW heads? I always thought that the larger intake valve would keep me from making low end torque. Does the low lift flow make up for it?
------------------ Robert 91GT; 88 ASC McLaren #709 |
Mine made more low end Tq than stock headed mustangs do.
------------------ Dustin Saleenized 89 GT,428 rwhp,TFS Street Heat Intake,TFS TW Heads,TFS #2 cam,BD-11A 9 psi,FRPP 1.6 rr's,BBK 70mm TB,Pro-M 75mm Bullet,MSD 6BTM, FMS 9mm wires,BBK longtubes,BBK Short H-pipe,American Thunder cat back,3.55's 12.3@119 |
Unit....when did TFS add you to thier marketing payroll?
------------------ 1993 GT/AOD '93 Mustang GT |
GT-40Ps weigh a lot more (50-70lbs) than comparable aluminum heads. You can't just compare flow numbers with flow numbers. What is it, 100 lbs cost you a tenth in the quarter? It's also weight in the front which is where you don't want it.
You can run more timing advance with aluminum heads since they dissipate heat better than iron heads. Unit's right about the TFS heads. They're the best bang for the buck. As far as torque goes, it depends on the cam and the length of your intake runners. TFS TW heads have no problems with low end torque and are great at the high end. ------------------ 351W 89 Mustang GT Convertible |
jimberg....About timing with aluminum heads. Has anyone here with aluminum heads played with timing on a dyno? I've heard people say you can run more with aluminum heads (which is probably true), but does that mean you'll make more power? I'm not trying to say that it is right/wrong to run more timing, but do you really need to since the design of an aluminum head is a lot more efficient than say the E7TE castings? Due to efficiency, I have been told that they need less timing. Of course this is all speculation. I have no proof either way, but I would like to see some dyno runs with a set of aluminum heads with timing at 10, 12, 14, 16, etc...to see what the differences in power are. Does anyone else have thoughts on this?
Back to the original topic....RobertD, I think you would be happy with any of the choices that were mentioned. I was thinking of going with Canfields (54cc chambers), but am now considering the Trick Flow TWs. But whatever you choose, in my opinion, will be better than stock. ------------------ 1989 lx notch 89,000 miles bolt-ons,stock heads/cam 60'- 2.07, 8.90@78, 13.93@99 |
I ran best with 18*. I tryed it at 16* and ran a run about 8 hp less.
------------------ Dustin Saleenized 89 GT,428 rwhp,TFS Street Heat Intake,TFS TW Heads,TFS #2 cam,BD-11A 9 psi,FRPP 1.6 rr's,BBK 70mm TB,Pro-M 75mm Bullet,MSD 6BTM, FMS 9mm wires,BBK longtubes,BBK Short H-pipe,American Thunder cat back,3.55's 12.3@119 |
Dustin....those results are pretty interesting. Was the gain seen throughout the entire curve or just at the peak? Also, how close was p/v clearance with the cam?
------------------ 1989 lx notch 89,000 miles bolt-ons,stock heads/cam 60'- 2.07, 8.90@78, 13.93@99 |
Go TFS you won't be disappointed. BUT make sure you measure the pushrods, and then get the correct ones. If not you WILL have problems.
XR1stang loves his TFS heads |
TJR-
The power curve was greater throughout the whole band, BUT it peaked at 8 hp more....I noticed a great improvement in throttle response too. P/V clearance was fine....they say TFS TW heads can go up ti .540 lift ot 290 duration, but I'd always use the clay method just incase. ------------------ Dustin Saleenized 89 GT,428 rwhp,TFS Street Heat Intake,TFS TW Heads,TFS #2 cam,BD-11A 9 psi,FRPP 1.6 rr's,BBK 70mm TB,Pro-M 75mm Bullet,MSD 6BTM, FMS 9mm wires,BBK longtubes,BBK Short H-pipe,American Thunder cat back,3.55's 12.3@119 |
I have thoughts on timing http://www.mustangworks.com/msgboard/smile.gif, and yes, tuning the timing on a dyno is the best thing to do. Too much timing will do more harm than good.
Advancing the timing will net you more power throughout the powerband since you are able to utilize more of the energy being released by the explosion of the air/fuel mixture. Bear with me since this is probably something that most people know, but it's a good idea to keep in mind and not all people know it. When we get our basic lesson on how four stroke engines work, we know that there is an intake stroke where air is sucked into the cylinder and fuel is injected. This is then compressed and ignited. Before I ever understood what timing was, I always assumed that the fuel was ignited at the top of the compression stroke and then the piston was just pushed down buy exploding gases. What they really do is start the explosion before the piston gets to TDC to get the mixture expanding during the compression stroke. It's kind of like compressing a super duty spring that then releases its full amount of potential energy after passing TDC. This is where it becomes relevant to the thread. The danger, though, is that if you start the expansion too early along with high combustion chamber temps, the fuel will spontaneously ignite (Detonation). My guess is that if you could take a movie of the explosion in super slomo, you'd see the explosion start up by the sparkplug and grow downward toward the piston. During detonation, all the fuel explodes at once before it reaches TDC. There's a lot of important information that can be derived from knowing this. When you advance timing, you increase the amount of potential energy that can be released after the piston reaches TDC. Cooler combustion chamber temps as a result of aluminum heads will allow you to advance your timing farther. Cooler combustion chamber temps as a result of running richer will also allow you to advance your timing farther. Octane is the lab measured amount of compression that fuel can take before it detonates. This is why you use a higher octane with high compression engines, or with engines that have advanced timing. High octane fuel also burns slower so using it with stock timing will give you less power since the amount of potential energy released at TDC will be less. This is why timing advance is important as engine RPMs go up. Since the piston is moving faster, it is important to start the expansion of gases earler so that you maintain your maximum amount of potential energy throughout the rpm range. There's probably a lot more, but I think you guys should have a good idea of what's going on. Before anyone harps on me about going into such detail on what we consider basic, there are a lot of people on this site and other sites who have no clue about this stuff. It's obvious in a lot of questions that are asked. ------------------ 351W 89 Mustang GT Convertible [This message has been edited by jimberg (edited 06-14-2001).] |
Just so you know what kind of time spans we're talking about here. At 1000 rpms, it takes the crank .06 secs to make a revolution. If advance is at 10 degrees it's about 0.0017 seconds of explosion time we're talking about. At 6000 rpms, it would take 62 degrees of advance to allow that much time, but with the speed and heat being generate, total advance can only be little more than half of that.
------------------ 351W 89 Mustang GT Convertible [This message has been edited by jimberg (edited 06-14-2001).] |
jimberg....That's a lot of info, I had to read it twice to catch everything I missed the first time http://www.mustangworks.com/msgboard/smile.gif.
------------------ 1989 lx notch 89,000 miles bolt-ons,stock heads/cam 60'- 2.07, 8.90@78, 13.93@99 |
I just hope it's useful info. http://www.mustangworks.com/msgboard/biggrin.gif
------------------ 351W 89 Mustang GT Convertible |
Quote:
I had a shop teacher adamantly maintain that no engine could be revved past 6,000 rpm or so (yeah rite!) since his calculations were based on a steady state burn (gasoline), unfortunately he didn't any other variables in account when he did the math! For a high RPM engine, a small chamber with a good R/S ratio is desirable, along with a port/chamber design which promotes good fuel atomization/homogezination. a. a small chamber reduces the time it takes to burn the A/F mixture across the chamber b. a high r/s ratio creates more piston dwell time at TDC c. highly atomized and homoginized fuel tends to burn more rapidly. |
Right, the timing isn't linear for another very obvious reason. By compressing the gases faster at higher RPM you generate more heat which will cause detonation earlier and earlier.
------------------ 351W 89 Mustang GT Convertible |
jimberg - how is the timing being non-linear (advances with rpm) going to discourage detonation?
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Sorry. That was unclear. Advance in degrees can be linear in relation to rpms, but advance in an actual time interval would not be. e.g. The 0.0017 seconds in above example.
The faster you compress a gas, the more heat will be generated since there is less time to dissipate the heat. This extra heat will add to the potential for detonation. ------------------ 351W 89 Mustang GT Convertible |
I think jimberg's been readin a lotta physics lately. http://www.mustangworks.com/msgboard/biggrin.gif
Mach 1 TFS added me to the payroll 3 months ago, they keep telling me the check's in the mail, but for some reason, it always get's lost? http://www.mustangworks.com/msgboard/tongue.gif |
Yeah, the old "check is in the mail story"...heard it a hundred times myself...lol.
I think Jimberg is confusing himself...... ------------------ 1993 GT/AOD '93 Mustang GT |
Trick Flows it is....
Thanks! ------------------ Robert 91GT; 88 ASC McLaren #709 |
Re: My head choice dilema...
Have you thought about AFR heads? Edelbrock is an excellent choice as well!!
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Re: My head choice dilema...
This thread is 3 1/2 years old. Whatever he decided, I'm sure its a done deal my now. :lol:
Andy |
Re: My head choice dilema...
I use TFTW heads and couldn't be happier. I have enough low end torque to smoke the tires with a C-4/3.25. I don't know what I would do with anymore low end torque. One other good thing about the TFTW, is that they have a raised valve cover rim that allows using roller rockers with poly-locks and still be able to use stock height valve covers.
On the other hand, I've heard that the AFR 165 heads are "kick ass" in the torque and power department. I think I would have been just as happy with those too. Rev |
Re: My head choice dilema...
Another vote for TW's...
Man, do I love them! Especially w/ 3.73's, but my neighbors for some reason don't appreciate them nearly as much. :D |
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