forcd ind

iTrader: (7)

Matt, what track-if Cecil I might come up and spectate

denmah

iTrader: (2)

tested out some CNC ported heads to see what they would do to this build


dyno test

soon to do TBSS intake swap test

truckdoug

iTrader: (25)

would love to see what a bigger cam would do on that same test.

Forcefed86

iTrader: (4)

I'd really like to see what it does with some decent RPM. 7k should be diddly on a 4.8...

94heritage

First off I just want to say thanks for taking the time to show everyone all of the different tests you do. My question is were the tests all ran with stock size valves or were they oversized? I never heard either way in the videos what they were.

douglee25

Good info man. I too was surprised you only picked up 20 hp up top.

Doug

BudRacing

iTrader: (3)

It didn't seem to increase much more than it would have on an NA motor. I was expecting it to have some compounding results.

408GT

iTrader: (2)

I read awhile back on "the nerd" build where he picked up about 25 whp from ported heads also:

https://www.theturboforums.com/threa...5#post-1994822

denmah

iTrader: (2)

it quits in the low 6s

all stock valves

well then it appears i am seeing the same thing

94heritage

I wonder if the valves are causing a restriction and thats why there isnt a bigger gain up top. The 40 hp down low would definitely be a good seat of the pants gain now if it could just carry it all the way to red line. Congrats on the little one and thanks again for all that you do for the community

Forcefed86

iTrader: (4)

Why would a “sloppy stage 2 cam” run out of steam in the low 6’s on a 4.8? Does that seem right to you? Factory ECU doing something funky? Spark blow out maybe?

JoeNova

Looks like a classic example of positive cam overlap and turbocharged high exhaust backpressure.

Forcefed86

iTrader: (4)

I get the “give a damn” factor isn’t very high on this build, but something sure seems off… Probably why the power didn’t carry through the whole rev range with the ported heads too.

The gains with porting alone on the factory valves (looked like the factor valve job too?) are pretty darn good!

JoeNova

Seeing as how he switched heads and valve springs and the curve didn't change much, I would say the only chance it has of being a valvetrain issue is incorrect length pushrod length.

What are the volts showing at 15 PSI? Is it dropping below 12 volts?

My money is still on the cam/turbo combo. I've seen it dozens of times.

3 window

iTrader: (1)

Any flow numbers on the heads? Just because the heads are ported doesn’t mean anything. They could flow like ****. I recall more than once a buddy flowing heads someone else ported to find the flow the same as an unported or even less in the crucial areas.

Game ova

[QUOTE][it quits in the low 6s/QUOTE] This shows that you don't have to rev a motor to the moon, to run fast. Seems everyone is all about turning 8500 rpm.

Forcefed86

iTrader: (4)

Not trying to dump on the build. I’m sure Matt could care less if the thing pulls to 7k. But… a typical mild cam NA 4.8 usually peaks around 7k+. It’s the nature of the smaller stroke engine. If it’s falling off at 6k there’s something wrong, regardless of the power it makes before then. Would be cool to find out what the issue is and see what the 4.8 is really capable of is all I’m saying.

I have tons of RPM related issues too, one of the reasons I was asking. Some of my stuff falls flat around 6500 no matter what I do. I’m talking 6-7 motors with all different turbo setups, ECM, Cams etc…

sbcgenII

iTrader: (1)

It picked up 40hp on low boost. It doesn’t matter what they flow.

forcd ind

iTrader: (7)

Is it still on the 4.8-def a bad azz little motor

Bad Apache

Yes, still on the 4.8l engine.