Couple Runs, NPB at 11.2

[98nbmz]

I paid right around 3 from summit I think

[Foose04]

Any thoughts on my stock timing chain with 89k miles on getting pissed off about this upgrade?

[1998ta__1991rs]

the partiot extremes are fine, thats what im using on my new motor, if anything you can upgrade to a ls2 chain, your stock should be fine

[BAD BOB]

stock should be fine with that mileage. just do the springs

[Carlrx7]

PAC-1518 springs. c5r katech timing chain. those plus a 228/228 .591/591 114 lsa cam. triple win!

[RobertHolton1]

truck is sick!!!

[ASkipper]

I remeber reading that the Patriot Extremes and the Texas Speed Springs are the same springs from the same manufacturer.

I may be wrong though but I do remeber reading along those lines on ls1tech awhile back. I would go with the double springs as I have read alot about the turbo setups and how boost needs a high rate spring pressure at a high psi rate. I remember parish8 tried to get the most out of a 4.8 in his truck and he had the same issue with springs.

Next time you go to the track just take the motor and butterfly off your cutout to make sure that it doesn't close back.

[ASkipper]

Originally Posted by RobertHolton1

truck is sick!!!

What he said ^^^.

[ASkipper]

Here is some post that parish8 made about trying to blow up a 4.8 and what it would do stock.

http://performancetrucks.net/forums/...d.php?t=245938

http://performancetrucks.net/forums/...d.php?t=243360

[Foose04]

Thanks for into guys. Yeah ASkipper parish8 is one of the guys I did a lot of research on prior to my build.

[98Camarod]

How did the times compare, with/without the 2step?

[ASkipper]

So what's the plan wring all you can out the 4.8 then up it to a 6.0 or bigger.

[DolSVT00]

Originally Posted by chrisheltra

Maybe Randy will chime in here because my memory is a little fuzzy here but I think Lightning heads stock are 90# and usually if increasing the boost past 18 psi it is recommended that you upgrade the springs. IIRC mine are 120#.

35# in stock PI heads

One of the first PI springs out there were 90# and later it was found that 110-120# were optimal.

Rob, I'm not even gonna begin to try and point you in any direction because I literally have 0 experience with your type engine combo. What works for us, may not work for you...... However we do have some similarities with regards to weight and aerodynamics.

I'll start out by saying, what works for cars in a similar engine transmission application, usually turns out to be shit for us and typically that's due to weight and aerodynamics above all.

I know your a turbo guy, and i'm sure you know all about bigger turbos and HP vs TQ. The a smaller turbo usually runs out of HP steam fast and starts making gobbs of TQ and hardly anymore HP, you want more HP get a bigger turbo slap it on and there it goes, but the byproduct is usually a drop in TQ at the same boost levels. Torque is important to us because like a tow diesel or anything else that moves weight real good they have gobbs of it, the same goes for us (well lightnings at least).

With that bigger turbo you have and less efficient transmission you may need to find something that gets you some torque back like a good cam with some mid range grunt while not sacrificing top end, but not soo large that you loose more in the middle and turn it into a top end roll car/dyno queen like a supra.

Now springs, I know your heads are different and I know that they flow better than ours, but this is what I personally learned. I put some 90# springs in my heads the first time, and when I started to make around 20 psi I noticed the power start to wobble and then abruptly tank and that was on a stock crap PI cam, I put some 135# PAC springs in and I noticed it hang on to the power a lot longer with the same cam, apparently I was getting some float at 90# closed and 20 PSI of boost.

I also noticed that the more CFM that I made at the same boost number from a better flowing blower would Blow out spark up top and kill my power up top. (not sure how much gap you have, but its another guess)

Cams, my truck woke up on cam's I was amazed how much I picked up on the top end with a really mild cam, I picked up a bunch of mid range TQ and top end HP on what would be considered a stage 1 cam (for our motor's).

In short and for us TQ= MPH vs HP for our transmission/ converter/ weight in a Lightning at least and the same may work for you.

[Foose04]

2Step is nice to be able set the rpm up. A 3600 cut me a 1.69, 3700 cut a 1.61, but was hit or miss on keeping on the brake. I think once the transbrake is working, it will work out real nice.

As to whats next after the 4.8L, i'm not 100% sure yet. I'd be jacked if I can keep the 4.8L alive for a bit but I know i'm playing around at a level most haven't.

[BAD BOB]

it will be ok, just do some springs and turn the boost up. maybe get a ams1000 to tune the boost to get it off the line the best

[ElecTech]

Originally Posted by DolSVT00

Now springs, I know your heads are different and I know that they flow better than ours, but this is what I personally learned. I put some 90# springs in my heads the first time, and when I started to make around 20 psi I noticed the power start to wobble and then abruptly tank and that was on a stock crap PI cam, I put some 135# PAC springs in and I noticed it hang on to the power a lot longer with the same cam, apparently I was getting some float at 90# closed and 20 PSI of boost.

The concept is very similar to injector delta pressure. If you do the math:

90# seat - 20# = 70# seat pressure

and this doesn't take into account the 20# applied to X sq. in. surface area of the back of the valve. This final value could be even lower.

[ElecTech]

Originally Posted by chrisheltra

I wouldnt touch patriot with your pecker.

The Patriot Extremes are probably the best thing Patriot sells. Good value for sure.

[DolSVT00]

Originally Posted by ElecTech

The Patriot Extremes are probably the best thing Patriot sells. Good value for sure.

Chris just hit em hard because anything and everything they sell for mod motor's are total garbage and have cost quite a few guys a ton of money fixing.

The mod motor guys would buy their heads for the port work (that we later found would cause leaks) and take the entire valve train and literally throw it in the trash.

From what I've read though they do much better on the GM stuff.

[ElecTech]

Originally Posted by DolSVT00

From what I've read though they do much better on the GM stuff.

Not really. Their flow numbers are weak on the GM side too. Most buy them because they are cheap and most don't know any better.

[minytrker]

Originally Posted by Foose04

I'm pretty sold on it being a spring problem though, atleast I hope so.

Thats my bet also. The springs have lasted way longer than I would have guessed, but you know I was against them from the start.