Hell yeah!!!!! My bro's Charger is going to be on its way back to Techco International for some more horsepower treatment. They will be dropping in one of their new 427 Hemi packages with the following specs: TPL-427D 427 cu in Bore- 4.082 Stroke-4.080 Comp 9.3 to 1 6.125 rod length “X Frame†Reverse Dome Piston Tool Steel Pins 4340 Forged Crank/with keyed dampner 4340 Forged Rods Blocks Prepped and machined on 4 axis CNC Mill Blocks Honed with torque plate CNC Ported Heads/with CNC Valve Job Beehive Valve springs Techco Supercharger Camshaft HP Range – 550- 900 rwhp (depending on boost Cam/Headers/etc). Sitting atop the new engine of course will be their Techco 3.0L Reverse Revolution Twin Screw Supercharger. They will also be installing a new upgraded transmission, new torque converter, new LSD, and halfshafts. A big props goes to Carlos Duran and the Techco crew, they have been nothing but professional and customer oriented throughout my experience with them. I look forward to seeing how this build goes and can't wait to take this beast to the track!!!
Why the 9.3 CR? Why not stock 10.3? Less boost required to make the HP. Less boost is better on the street.
hmm the bore and stroke listed would be less than a 426. The 4.082 squared equates to a true 426. Or am I wrong?
You are one of the Forum heads, you are never wrong!! I don't know, I am sure Carlos will tell us. If memory serves me right Ford was more than a liter off on the 5.0L....I don't even think the bore and stroke came to 304 cu.in. much less 305.... Let's wait for 'Los to weigh in..........
Bro is looking for a daily driver and keeping the Charger for fun buddy... Maybe I am wrong: CID=0.7854*stroke*bore*bore*number of cylinders .7854*4.080*4.082*4.082*8=427.
Do 10.3 CR. What if you decide to take the SC off someday? Listen to the old guy. Why run more boost than needed? More boost is more stress. 4.08X4.08 = 426.7370568615318 4.082X4.08 = 427.1655290667057
First off...We wanted to do something different from everyone else. This is why we released our 397/427 program for the dodge crowd. So far the response has been 50/50 on the 427 becuase of what it is linked to. Secondly..I was raised to respect my elders and we will listen to the old guy. :salut: currently we are building engines for N/A customers and sc customers and we have even done special ratios from 8.5 to 10.3. There are so many variations you can do and everyone has a valid reason on why it should be done. If a customer requests we will built 10:3 all day long N/A. Currently we are building 427's for supercharged cars with a true supercharged cam. Anything you think that you might of lost with the point of compression is more then made up for with the cubic inch increase. The motor specs we have are for supercharged applications BUT if someone requests N/A we can assist.
So an 8.5 to 9.3 CR 426/427 will make the same HP as a 10.3 426/427 with the same boost? Carlos, I just don't see the rational to build lower compression motors for street cars. These aren't race cars. Why run more boost than you have to? Why put more stress than necessary on the blower, pistons, etc. I believe most pick lower compression for street out of lack of knowledge. What if someone decides to take off his SC, say becasue it never gets CARB certified, and gets busted and told to remove it, or he justs wants to remove it to run NA or with N2O? If he's going to run it NA after that, I'm sorry the lower compression motor will not make up the HP because of more cubes. It has the same cubes. I know this has been a debatable topic for many years. So Carlso, do you recommend lower boost for the street, and if so, why? Inquiring minds want to know.
Halv after discussing it with you and looking at that great article I am now in the process of my build and I believe you are right about the compression. I am trying to see where but I will not go lower than 9.5 but I think I might keep it at 10.3.
Here, let me help. haha I completely agree with the resident OLD guy (wow, there are firsts. haha) When my first motor was built, we went 9.5:1 CR for several reasons. Mainly because it was BEFORE tuning and we did not know how the PCM and SS ECU were going to react. And, because I had planned on going higher than 12psi when tuning was available. lol My new motor will be 10.3:1 CR since I will only be running 10psi. If I planned on 16psi or higher, the CR would have been lowered. No sense in Robbing the motor of horse power when not needed.
On Compression ratios, as the specs we are putting out are all for the SC engine, we are going for lower 9s as this is what we have found over the years and literally 1000s of engine builds to be the best all around for both performance and safety. While i do agree completly that to a point if you are running good gas, and can run the same spark timing that more Compression is better. However we are building street motors running on down to 91 oct. we have found that a little lower comp, allows a more "normal" tune for spark, which more then make up for the point of compression. This is the same that the main OEMs do for there sc engines (ford gt -40 , Gt 500, corvette ZR1, etc, all 9 to 1 or LESS) having an extra point on the street , that has to run 8 less deg of spark does not do you alot of good. If you have good gas (like race gas) and can run the same spark values on each (9 vs 10) the 10 will win, (up to a point when the boost level overwhelms it) However when you add constanly changing street gas, the lower compression is going to allow you to run a more normal spark that the cylinder head was designed for. You will make the same or better power with less comp. this also allows the customer to go higher with boost in the future if wanted. If you want to build a NA engine then we will go higher, we do this on our 5 liter ford we do, 9.5 on the SC- 10.5 on the NA. This is our opinion on this from our experince in the past.
