When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
What about the stock plenum and base being ported to match the larger runners.?
Totally, just looking for the biggest numbers anybody has seen out of a stock plenum setup.
I saw a guy claiming some pretty big number from a 383 setup with a Stock TPI setup, but couldn't provide any Dyno proof. Just wondering if it was possible.
There's something a little fishy about that article. It was written a couple years later by the same guy that wrote Ten Times the Torque, The Ultimate TPI Shootout (there's a lot of info in the TPI sticky about it). https://www.thirdgen.org/forums/tpi/...feb-super.html
The engine in the “10 Times” article is a 10:1 383 with Trick Flow heads (no size or any other info given) and a Comp XR288HR-10 cam (288/294, 236/242, 0.520/0.540). I estimated that the head flow needed to produce the numbers for all those combinations tested had to be at least 265cfm on the intake, and later it was speculated they were probably TFS 195s.(maybe ported - who knows). It wasn't specified, but the headers appear to be 1.75" using a torque tube with a 3" MagnaFlow round mufflers.
Using the same extrude honed base and plenum with the large tube runners as that standalone article it was reported to produce 451HP and 534TQ - no RPM data, just the graphs.
A number of the same pictures were used in both articles, which it is not uncommon to reuse and relatively common to recycle an article, or break out stuff from one to make another years later. However, here’s my “issue”.
The standalone article is a 10.6:1 383 using Extrude Honed “L98 Aluminum Heads” (article says flowing 260cfm) and a XR264HR-10 cam (264/270, 212/218, 0.487/0.495). Headers are said to be 1.625" with 3' MagnaFlows. I scaled the grafts of the same extruded honed intake used in both articles and for all intents and purposes they’re the same (see below –the differences are within dyno tolerances).
There’s very little to no chance that the engines spec’ed in those articles could lay down near identical power curves. Maybe he pulled the wrong dyno file from the computer when sending to the publisher?
EDIT - Looks like I'm a few years late to the party - found the link below where folks back in 2007 immediately started questioning these results and includes a response from the author regarding those questions. I still think the graphs are too close not to have been mixed up. https://www.thirdgen.org/forums/tpi/...ml#post3217154
Not trying to dig at you, but dyno results, and time slips?? To make 380 rwhp through a 700r4 with a 10 bolt you are talking about a 500 hp small block.
If its true and you did it with iron heads.. I really need to see this, I can learn from it!!
I'd love to see the v.e and bsfc numbers from the dyno.
Originally Posted by Fast355
10.5:1 Vorte 383 made 380 wheel through a 700r4 and 8.5" 10 bolt.
Ported 3817 Vortec base, siamesed SLPs, and reworked upper plenum.
Not trying to dig at you, but dyno results, and time slips?? To make 380 rwhp through a 700r4 with a 10 bolt you are talking about a 500 hp small block.
If its true and you did it with iron heads.. I really need to see this, I can learn from it!!
I'd love to see the v.e and bsfc numbers from the dyno.
13.7 @ 101-102 mph was the 1/4. Ran about a 2.1 or 2.2 60' on street tires with a 3.08 rear gear and stock 1,600 rpm converter. Vehicle was 5,300 lbs and had the aerodynamics of a house.
Was never on an engine dyno, just chassis.
The 7730 had the VE table (fuel map) maxed out at 70 kpa and 2,800 rpm. I had to tell the computer it had smaller injectors and go with a higher PE Fuel multiplier to get the pulse width to get enough fuel at WOT. It ran LT4 28 lb/hr injectors running at 50 psi and had them maxed out at about 98-100% duty cycle.
Heads were 906 vortecs with 2.05/1.6 valves, flowing 260ish cfm intake and 220 exhaust. Chambers were deshrouded a bit at around 68cc with a 0.020" mill.
Bottom end was a Mercruiser 6.3 rotating assembly from a freeze cracked block, put into a 4 bolt main Vortec truck block that had been freshened up, zero decked and had a 0.040" quench. Mercruiser 6.3 is 4.00 x 3.80".
Cam was a 232/240 @ .050 roller on a 108 LSA with 0.550 lift using 1.6 rockers.
Thorley tri-y headers into dual 2.5" exhaust with a X-pipe.
700r4 and 8.5 10 bolt loses about 18%. That makes 380 hp at the wheel around 465 hp flywheel. It also made 410 tq at the wheels. HP peak was about 5,400 rpm. TQ peak about 3,400.
That engine ran good, but my newest 383 easily makes another 60-70 HP than that one. It is 11:1 with 6" rods. Has aluminum heads that flow 299 cfm. Has a similar cam (232/244 @ .050, 108 LSA, .554 lift with 1.7 rockers that give .640 lift but also has Rhoads VMax lifters. It has a heavily ported dual plane mpi intake and 1,200 cfm 4bbl throttle body. The torque curve is broader and flatter. It makes as much peak torque but carries the curve much higher on both the low-end and high end than the TPI based stuff. Chassis dyno is not a straight across comparison on this one. As it has a 4L85E and GM 10.5" full float rear behind it. It also has a large mechanical clutch fan with an aggressive clutch to keep it cool. It is in a vehicle that is 900 lbs heavier but has a 2,800 stall converter and 5.13 gears. I have not run a 1/4 in it but it has hit a 4.8s 0-60 and an 8.50 1/8 mile using a performance app in the OBD2 logging I use. At the 1/8 mile it was running 82 mph. I figure the current combo is good for mid 13s at about 100-102 mph. It really moves for a 3 ton brick. It also yanks my 6,000 lbs travel trailer around like nothing. Climbing up the old Cedar Hill on I-20 leaving Grand Prarie on my way to the beach with the cruise set to 70 mph, it drops one gear to 3rd, jumps up to 4,000 rpm and stays right at 70 mph. The cruise can hit about 75% throttle opening which partially opens the secondary throttle bores. 4 banger cars have a hard time staying out of my way with the trailer on that grade.
I have 2 different shifting patterns for it depending on if I am towing or not. In normal mode it shifts WOT at 6,200 rpm and holds off lockup until 4th gear. Towing it shifts at 5,500 rpm and locks the converter shortly after the 1-2 shift and keeps it locked all the way through the gears even at WOT. Converter was stock diameter built with a billet front cover and larger heavy duty lockup clutch to allow this. Modified to get as much STR aka torque multiplication as possible.
Because I tow and wanted it to be conservative I only run 26° of timing on 91+ octane fuel with a WOT air/fuel ratio around 12.5:1. I plan to play around with the E85 tables someday soon but need a fuel pump upgrade before I can do that. Really needs a 340 lph fuel pump in it. So far the factory replacement Delphi pump with a Racetronix Hotwire is holding 58 psi at WOT but it will be far thirstier on E85.
I have thought about adding water/methanol injection to it. Just have not found the time. I have enough room under it to easily add a 5 gallon tank and a pump. With the added octane and cooling I am sure I could run 30-32° of timing and air/fuel around 13-13.2 for more power even on 87 octane. I would put it on a Hobbs switch to turn on with low manifold vacuum.
05-04-2020, 06:58 AM
