TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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I've been looking at a new Rotating Assembly, I started a thread called 383 Breathing Issues, but it got filled with jibberish. I was looking at the 396 assembly from TPIS. Anyone familiar with it or the regular 383? Is there anything I should look out for before mating more cubes to the TPI setup???
Plenty running TPI on 383's but the TPI was designed for the 305 and barely feeds a 350 let alone a 383+ Output will be severely limited by TPI ; depends what you are looking for.
Many would say
"why go to the added expense a 396 for increased HP and then strangle it with a TPI?"
396 is a lot more work in clearancing block for increased stroke and prob requires small base circle cam which is why 383 is more common
( cheaper ) option
Because 396 is less common the pistons are more expensive than 383 ones
Do any of the members here who have the 383 TPI, have any feedback? Maybe such as yourself? I am just want to be sure of what I'm doing, I do not want to buy my rotating assembly only to be disappointed.
As noted most change the intake to optimise the benefits of the larger engine.
I used a well modified TPI ( SLP big tubes , ported plenum , siamised base ,30 lb injectors ,58mm TB ) on my new 383 to run it in with.
Killer bottom end and throttle response ;datalogs showed it reving past 6K but I know from the TPI graphs, power would not be increasing much over 5K
12.7 with A4 and 3.07 rear.
Swap intake to HSR , minor tune adjustment to spark advance ; ran 12.3 ( with a better tune would have gone faster )
Pick your poison
If you are not into big Hp and revs I say do it; you will blow any body off from the stop lights on torque alone IF you can get traction
I Built a stroker 395 (maybe same as your 396) for my '87 IROCZ. Great torque, lots of fun to drive. However, I would not run a factory TPI unit on top of it. The 395 is a 30 thousands over 350 block with a 3.875" stroker crank. And as stated above the crank and pistons are less common. Check out my sig. Any specific questions?
__________________ '87 L98 TPI IROCZ, 395cu.in. ZZ4 block (.030" over bore), ported Holley StealthRam; 3.875" Callies DragonSlayer crank, 5.85" Eagle H-beam rods, 14cc dished SRP pistons part# 148988, AFR190 heads, 3.70 rear gears, 224*/230* 114*LSA 0.530/0.536 lift CompCams cam, 1.6 roller rockers, 3000 Art Carr TC, SLP 1 3/4" headers, SLP cat-back, no cat, no AC, MAF w/o screens, 30#/hr Ford injectors, 52mm TB with airfoil, TB coolant bypass, Lay Ind. ram air kit, SS Brakes 1LE upgrade 12" rotors dual piston calipers, turbo TransAm fuel pump, K.Brown weld-on subframes. Rear tires: P295/35R18 BFG Drag Radials.
Best ET 12.12 sec @ 110.55 mph @ Milan.
With 395, ET 12.197 sec @ 113.65 mph @ Milan.
With 350, ET 12.97sec @ 105mph M/T ET Streets.
Best with HSR: ET 12.385 sec @ 108mph @ OSW.
As I said if you are not into all out Hp then TPI will make killer bottom end engine but you will be leaving a lot on the table ( especially with extra expense of a 396 ) if you run a LTR style intake vs a HSR /SR / MR
SixseriesCSi: You will do very well with what you have. I must not be very smart because Orr in Pittsburgh is running in the 11s with a 383, and another guy has run my same ET with a 30 over 350 (which is a 355). So, I must be a bit challenged here.
For you, I like what you have. Install an adjustable fuel pressure regulator (AFPR) so that you can controll the fuel pressure to better dial in 12.8:1 AFR at WOT. Also, get a good fuel pressure gauge. Match port the LTR to the manifold and the plenum. You can even siamese (sp) the ports in the plenum. And open up the inlet end of the plenum to match the 54mm TB. If I remember correctly, there is a restriction just inside the plenum behind the TB. Grind some of that away and smooth it out. Now tune the ECM. You should be able to run in the 12s and have great torque on the bottom end. The car should be alot of fun to drive.
SixseriesCSi: You will do very well with what you have. I must not be very smart because Orr in Pittsburgh is running in the 11s with a 383, and another guy has run my same ET with a 30 over 350 (which is a 355). So, I must be a bit challenged here.
For you, I like what you have. Install an adjustable fuel pressure regulator (AFPR) so that you can controll the fuel pressure to better dial in 12.8:1 AFR at WOT. Also, get a good fuel pressure gauge. Match port the LTR to the manifold and the plenum. You can even siamese (sp) the ports in the plenum. And open up the inlet end of the plenum to match the 54mm TB. If I remember correctly, there is a restriction just inside the plenum behind the TB. Grind some of that away and smooth it out. Now tune the ECM. You should be able to run in the 12s and have great torque on the bottom end. The car should be alot of fun to drive.
Actually, Orr now runs a 400+ motor with twin turbos and is in the 9's...
My motor 2 seasons ago was a healthy 383 (nice cam, good Dart heads) and I ran the TPIS Bigmouth intake, SLP runners, 58mm TB and a heavily worked over upper plenum. The motor ran great but when I swapped over to a HSR it was certainly noticable where the car pulled in the upper RPM's compared to when the TPI style intake was bolted on.