Couple Runs, NPB at 11.2

[Foose04]

First want to thank Darryl and Zach for taping a couple runs. I enjoy looking over the video's just as much as I do racing, so thanks again.

Made a new best, that said I've hit a wall and the trucks making the same power even as boost rises. Pretty much at the same power it did with the old 70mm turbo, even at the same boost now 76GTS.

First off I've found couple problems. If you notice in the video's, the truck is pretty damn quiet on the back half and second run. Well my first Jegs brand cutout stopped working and now this one is closing during my runs. It's nearly shut after a pass. My after cutout exhaust is less then impressive press-bent 2.5inch piping and another muffler.

Other then exhaust I think the LS6 valve springs may be opening up when boost is at or around 14-15psi, so there is no gains above that? Thoughts?

Here's the runs : http://youtu.be/aSKJSHVN-rw?hd=1

[CINDERBLOCK]

trucks running good man... I couldnt make the trip up there this weekend. Went to Bowman instead.

[1iron]

I'm not sure what you are saying about boost opening the valves. Never heard of that. More boost = more power. If a small turbo can make the same boost it should make the same power if everything else is the same.

[98nbmz]

Boost doesn't matter so much as backpressure. A car with a more efficient turbo system (less backpressure) can actually get away with less spring.

As an example 20lbs of boost going through the intake isn't going to effect anything when the valve is on the seat. When the intake valve opens you have flow into the cylinder and pressure is trying to equalize between the intake and the cylinder. As you reach intake valve closing the compression cycle starts and pressure in the cylinder immediately eclipses pressure behind the intake valve.

On the exhaust side however you may as an example have 40psi backpressure. As the exhaust valve is closing your intake valve starts opening (overlap) and there is still 40psi on the back of the valve but little pressure in the cylinder to balance it. At this point you can bounce the exhaust valve causing a drastic loss in rpm/power.

For the hyd roller stuff that's going to see 20psi boost I usually run a spring with around 400lb/in rate so I can get 200lbs on the seat and 425 or so over the nose. Seat pressure is what's important here.

That is very generalized and like anything else should be decided on when selecting the rest of the parts for the combination. I can say with certainty that 918's will not be enough for a turbo LS1 that will see 20psi boost

Taken from ls1tech, maybe itll help

[silver fox]

Check your waste gate or blow off valve. The spring might be getting weak and can't hold the increase pressure.

[chrisheltra]

Congrats. Your slowly creeping up on the 10's just like me. Its frustrating as hell isn't it?

[bwelch]

How much air are running in the hoosiers?

[Foose04]

Hoosier's were run at 13 cold, around 14 after a pass.

My boost reference is measured at the manifold, so the wastegate and BOV are working fine.

I have a bottle kneck for sure though. I can share HPTuners logs, but I got about 1.5MPH gain going from 14psi to 19-20psi boost. Also I only used a couple more % fuel, so the way I see it, the air's not moving through the engine.

Thanks for the info 98nbmz, i'm going research more on the springs.

Chris, it is a little frustrating. Seems like I "should" have had it a few trips ago.

[1iron]

Boost doesn't matter so much as backpressure. A car with a more efficient turbo system (less backpressure) can actually get away with less spring.

As an example 20lbs of boost going through the intake isn't going to effect anything when the valve is on the seat. When the intake valve opens you have flow into the cylinder and pressure is trying to equalize between the intake and the cylinder. As you reach intake valve closing the compression cycle starts and pressure in the cylinder immediately eclipses pressure behind the intake valve.

On the exhaust side however you may as an example have 40psi backpressure. As the exhaust valve is closing your intake valve starts opening (overlap) and there is still 40psi on the back of the valve but little pressure in the cylinder to balance it. At this point you can bounce the exhaust valve causing a drastic loss in rpm/power.

For the hyd roller stuff that's going to see 20psi boost I usually run a spring with around 400lb/in rate so I can get 200lbs on the seat and 425 or so over the nose. Seat pressure is what's important here.

That is very generalized and like anything else should be decided on when selecting the rest of the parts for the combination. I can say with certainty that 918's will not be enough for a turbo LS1 that will see 20psi boost

Taken from ls1tech, maybe itll help

So the cutouts not staying open might be the issue?

[Foose04]

It's not helping thats for sure, but I still feel something else is holding me back.

[chrisheltra]

Whats the seat pressure on the LS6 springs?

[Foose04]

90 lbs. @ 1.8 in., 295 lbs @ 1.250 in., .570 in. Maximum Lift

[98nbmz]

I bet its the springs/seat pressure. Why not do a cam and spring swap?

[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#. I'm unsure if springs and valves and all that jazz respond differently because of different head design and 90# is sufficient for you or not, but that may be were some of your issues are coming from. Not enough seat pressure and your turbo is pushing the valves open which will cause some boost bleed off. This is all purely speculation and not a professional diagnosis.

[BAD BOB]

it could be pushing the valves open. when i put the stock heads on mine it was need to have the springs replaced to a set of dual springs with good seat pressure.

So what is the issue that you are having? just that the new turbo isnt doing any more than the old? and the exhaust, depending on what is on it, does have that much effect on the turbo unless its really restrictive. my car runs through full exhaust and does pretty good

[98nbmz]

Look at patriot extremes not too expensive at 250 bucks

[Foose04]

Yeah the main issue is 13.5-14psi run 11.3@119-120. Last run was mostly 20psi, ran 11.2@119. No knock, same timing, safe a/f's. The only reason it went 11.2 was because of the better 60, the HP the truck is making is staying the same.

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

[chrisheltra]

Look at patriot extremes not too expensive at 250 bucks

I wouldnt touch patriot with your pecker.

[BAD BOB]

i got some from texas speed and they were around 350 but said to be very good for my application with the turbo. just try them and see what they do

[98nbmz]

Or Ford

I wouldnt touch patriot with your pecker.

[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]

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/showthread.php?t=245938

http://performancetrucks.net/forums/showthread.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]

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]

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]

I wouldnt touch patriot with your pecker.

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

[DolSVT00]

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]

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]

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.

[98Camarod]

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.

x2 :bigthumb:

I've got my old motor that has a comp 230/230 cam, prc duals, cloyes hex-a-just timing chain, melling oil pump, comp lifters for sale if you want that

[OUTLAW]

First want to thank Darryl and Zach for taping a couple runs. I enjoy looking over the video's just as much as I do racing, so thanks again.

Made a new best, that said I've hit a wall and the trucks making the same power even as boost rises. Pretty much at the same power it did with the old 70mm turbo, even at the same boost now 76GTS.

First off I've found couple problems. If you notice in the video's, the truck is pretty damn quiet on the back half and second run. Well my first Jegs brand cutout stopped working and now this one is closing during my runs. It's nearly shut after a pass. My after cutout exhaust is less then impressive press-bent 2.5inch piping and another muffler.

Other then exhaust I think the LS6 valve springs may be opening up when boost is at or around 14-15psi, so there is no gains above that? Thoughts?

Here's the runs : http://youtu.be/aSKJSHVN-rw?hd=1

hey seen you at the track that is 1 fast truck:bigthumb:

[Foose04]

Thank you sir, she don't run bad for a heavy weight. :cheers

What car you run Outlaw, I wanted to say I met you at some point.

[Foose04]

Well I spoke with the guys over at PAC yesterday, they said their 1518's would handle my application just fine. I decided on those because I really don't feel I need something as aggressive as the duals for a .550 lift cam and stock timing chain. I just need some seat pressure to provide some valve control for another 3-4psi. After that, this setup (short block) is to a point i'd rather not push further.

If I build something down the road and want more seat pressure I have the option to shimming them as most FI cam's still don't have monster lift.

[Audie1]

A lot of good advice given here from some very knowledgeable folks. As a turbo guy I know a thing or two about turbo setups and their problems. Some simple things to check that rob power are vacuum lines. Make sure that they are not cracked or even old. I change mine out every year. Some will seem like they are fine, but when they get hot they can balloon up and you wind up loosing pressure. I use small zip ties and put them on both ends of the lines and make sure they are tight. If your are not making anymore power with the bigger turbo then I would agree with your earlier stated suspicions about there being a bottleneck somewhere. I've never seen your engine setup so I can only throw out some suggestions. Does your intercooler have adaquite sized inlet and outlet ports, is the intercooler large enough to support your engines power level? Is all your piping going to and from your intercooler large enough so that they are not creating a bottleneck? Do you have an EGR Valve, if so is it working and clean (they get gunked up sometimes and can hang open)? Exhaust leaks anywhere between the headers to the down pipe are big power robbers and can drasticially slow down your spool up times. Are your headgaskets good and torqued down correctly? Do you have an automatic trans, and if so could it be slipping? Please don't take any offense if some of these questions might seem rather obvious and simple, as I'm just writing any possibilities down here that I can think up....:cheers...Are all your hose clamps good and tight? What type of Boost Controler are you using? Are you getting any boost creep or is your boost steady? If it's creeping then you may need to increase the size of your wastegate puck hole. Do you have a big enough wastegate and is it in good shape and not sticking? If it is not big enough then there is another possible a bottleneck. I would check out some of the simpler things before changing out your valve springs. But stiffer springs and a better cam will not hurt either (as some of the guys already stated). What is your static compression ratio? You said that you are running 20# of boost? What are you gapping your plugs to? I'm running 25+ # of boost and higher boost levels usually require a tighter gap, as was mentioned in an earlier post. On my Buick I run a gap of .032 instead of .035 to prevent the spark from getting blown out. What type of gauges etc are you using to monitor your air/fuel/timing etc? Just asked to make sure you are not getting any knock that would retard your timing. Do you have a knock gauge or audible alarm to sense knock? I'm sure your on top of those things or you would not be running as fast as you are. Just a few suggestions here, you've probably already checked these things, but I'm just trying to pitch in my two cents worth.....Hope you get it figured out though....:cheers

[Foose04]

Damn Audie, you pretty much covered all the bases. This should be a pre-flight checklist every time I head to the track.

I'll check and double check a few things and update the forum once I make some progress.

Thanks again for the tips.

[Derek]

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.

:hide:

[98nbmz]

http://www.ls1tech.com/forums/parts-classifieds/1380822-patriot-extreme-dual-springs.html

[Foose04]

Well I got the PAC 1518's in from texas speed but haven't installed them... work has been kicking my ass so I took the easy route and finished up the bottle setup so I can use it at the track.

Installed the purge and bottle heater on a switch. Just running a 50 shot, but hope to have enough to trim that .2 off and breaks 10s. I don't know, this fatty truck eats HP...

GoPro Hero is pretty sweet for daytime shots, but pretty rough at night. Over all very happy with hardware it comes with and setup. I'll have that little bad boy with me tomorrow.

God speed to the GM.


http://www.youtube.com/watch?v=gy3CPk15hgk&hd=1

[PapaBear]

Where is this road?

[Matts94Z28]

Next to lincolnville road.

[bambooi]

I installed pac1518s from texas speed too when I had my vette. I removed the ls6 springs asap because of the horror stories...

[Carlrx7]

Next to lincolnville road.

SHHHH, if i hear you, u owe me 5 bucks! just follow the road and drop the money in the 5th mailbox on the left

[chrisheltra]

I bet your chevy forum buddies think your crazy for running a turbo and nitrous on a stock block.

[Matts94Z28]

SHHHH, if i hear you, u owe me 5 bucks! just follow the road and drop the money in the 5th mailbox on the left

Pffttt. I used to race on that road back in 03! Some guy who had a blue 350z used to come check it out back then.

[Foose04]

Yeah it's on Carls drag and tune road. I've made about 5-6 runs now, feeling good about the tune.

Chris most the GM forum guys thought my truck would let go 15k miles ago and around 10psi. I didn't know much about the engine and it's limit's, but i'm willing to push the bar for sure. I consider myself ok behind the laptop with tuning, most people told me I'd never keep a 110MPH 1/8 mile talon together for 4 year and 90k miles on a built block I bought used, but I did.

Well see, i'm having fun with it right now and I think thats all that matters.

[Chillerman]

All I know is that truck haul's the groceries pretty darn quick. I hope you get your issues worked out and break into the 10s.

[chrisheltra]

All I know is that truck haul's the groceries pretty darn quick. I hope you get your issues worked out and break into the 10s.

+1

But I hope I get a 10 first. :hide:

:hysterical: