Rabidbandit

Well....we swapped on the 'ol Weiand on Bill's car and dyno tuned at TTP Sat. We lost a little more than 30 freakin' hp at the wheels This manifold is crap. I can't believe that they say it flows 15% more than the Z06 manifold. Manifold temp at the TB was 144deg. plus....it got way hotter down the road and that was outside temp. That's what we get for buying something purdy...we'll stick with the LS6 for now and maybe a FAST 90/90 later. Just wanted to share my dissappointment. His brothers car tossed a trans on the way to TTP...he made it back but with teeth missing and glitter soup after we opened it up. So it was overall a pretty bad day

brad8266

iTrader: (23)

that sucks.

TheBlurLS1

iTrader: (8)

Are you sure something wasn't installed wrong? I've seen a bunch of people make power with those (around the same or a bit more than an LS6) so it sounds like you might have had a vacuum leak or something.

If there's nothing wrong with it, sell that bad boy. Some people like them just for the bling factor.

300bhp/ton

How'd you dyno with the tranny out?

Also I don't doubt that Weiland is no better (maybe worse) than the LS6 but I doubt it's 30rwhp worse.

Remember dyno's vary all the time, or did you do a base run on the same day with the LS6, plus you'd need to use SAE corrected figures to be able to compare.

An example would be, same car, same dyno, same setup and mods dyno's two days apart and results in a 20rwhp variance with STD results. Once corrected to SAE there was less than 0.5rwhp between the readings.

brad8266

iTrader: (23)

he said it was his brothers car that the tranny broke on.

Rabidbandit

Sorry...I'll clear the trans thing up. Bill's car is the blown 2000 T/A....Mark..his brother had a 1998 T/A with a auto...he then converted to a 6-Speed. Mark's trans took a crap...Bill's car dynoed 30 less. Mark was supposed to dyno his but you can see why he didn't. As far as vacuum leaks on Bill's car...none what so ever. Idles great! These were SAE corrected figures but done at different times. Temp and Humidity could have been a factor...but we still took a hell of a hit. Matt from TTP can verify our dissappointment All fittings and gaskets were properly seated. I'm stumped!

Rabidbandit

We did lose a little boost...went from 8-9 to 6.5-7#s. I wonder if that damn piece of sheet metal under the intake is sealed under vacuum but leaks under boost??? It looked a little cheesy. Before you say it....yes we checked the airfilter, intercooler plumbing, and everthing that holds boost up to the TB for blown off hoses. Everything is tight. I can't believe a manifold was this bad. If I'm missing something...tell me...I don't usually bash products....especially the Weiand/Holley line...but damn Edit: I had to add...this was the replacement of the LS1 manifold that was on the car...he's buying the LS6 from his roommate to replace the weiand.

TheBlurLS1

iTrader: (8)

I think I'd blame the drop on the 2-2.5psi in boost lost instead of the intake manifold. 30rwhp is insane-o power loss.

NoMoreLS1

iTrader: (65)

Well... losing boost will cause a drop in power. When you "open things up" with a manifold change, that'll happen. Do you do any tuning? Do a pulley swap and tune it.

300bhp/ton

Right there's no way you should loose 30rwho over a LS1 intake, as that'd be about 50rwhp less PEAK than a LS6 intake and upto 70rwhp less than a FAST 90/90.

Remember boost is a measure of restriction and not airflow. If you lost boost it will be down to less restriction, i.e. better flowing exhuast or something. This would mean the same amout of air flow but it isn't being "bottle necked" so you'd end up with the same gain but with less boost/effort.

However I don't believe this is the case here. If nothing else was changed/altered then the most likely cause is a boost leak, which will of course show up as a power loss.

Do you know where the boost pressure sensor gets it's reading? Is the manifold tapped and taking the reading from there, or is it straight off the turbo/supercharger?

rocketman442

iTrader: (8)

You lost 30 hp from a LS1!!! I'd be looking into the boost loss, thats where you power went.

Rabidbandit

Here's the kicker...The pulley on the ATI is the 3.2....It's already bumped up. The boost gauge is on the back of the manifold. The boost decrease I agree with as far as the better flow. Here's another question...if the air is hotter in the intake (less dense air charge) Would that drop boost being that the compressor has to spin faster to overcome the thinner air to produce the same boost??? There are NO leaks on this manifold...at all...the only part that's a culpret is that access plate on the bottom. I don't want to fire up the age old topic of heat soak...because you guys are tired of hearing about it. Something's definately wrong here...nothing changed on this car except the intake...like I said...Idles and drive like a dream....The fuel tables on the dyno were just a tad rich at WOT....but pretty damn close. Arrggg

Detroitmuscle

iTrader: (16)

I'm gonna guess you don't have the manifold sealed correctly. I helped my friend install his and it seemed to be fine but does act funny (only once in a while) with idle now and then which indicates boost leak. My friend works at Wheel2Wheel and one of the salesmen there told him that not only do you need to replace the coolant pipes with the LS6 ones but you also need to change out the valley cover bolts to the flat allen head ones like the ones that come with the FAST intake. I am guessing this is the problem as many people don't do it and end up with a leak. Take off the manifold and install the new bolts and see if you get back to 8-9#

LS1-450

iTrader: (33)

Did you check port alignment? Mine overlapped the runners on the heads by 1/16" to an 1/8" prior to port matching. Use high temp silicone to seal the bottom (sheet metal cover). Were the phenolic gaskets used to insolate the intake from the heads & TB? How 'bout timing tables; were they the same? Any knock retard?

Since boost & power were down, I'd agree that it's boost related. Check the port matching, silicone the under plate, & try again. Also as mentioned, take a base run to measure against. 30HP from dyno to dyno or day to day isn't un heard of.

Rabidbandit

We already replaced the the coolant lines on the back with the LS6 conv. The valley pan bolts don't hit. I may not own an F or Y-body car...but I turn wrenches on about 5 of them (It by no means makes me an expert but...I have an idea). I'm pretty good at checking and re-checking bolt-ons...no room for error. My reputation with the owners is very important to me. If it was something as simple as incorrectly installing a manifold I'd might as well quit what I love...but with that said...we did dry installs with and without gaskets to be sure. If it was a boost leak from improper gasket positioning or manifold alignment...it would be a vac leak as well! The IAC is showing the same values (within 2%) as the stock intake. Heat and humidity could have been a factor in HP/TQ....I need to hear from someone that has used this intake with the P1SC, 3.2 pulley, 6-Speed, Stock cam, and 4.10's. Thanks for covering all the bases though. All of your guys' responses are really appreciated...checking items you have mentioned are always worth the looking at...even if me or anyone else has already covered it

Rabidbandit

Yep...timing tables unchanged...used high temp on the gaskets that meet the head...not on the bottom though....if it was leaking...I'd see a change in the IAC wouldn't I?

00454sscamaro

with tests on these manifolds in the magazines i get. one swap from a ls1 intake on a f body they lost hp switching to the aluminum manifold, another with a corvette they gained like 10rwhp with the intake tb and blackwing airfilter. the only one that actually gained hp had other parts to help it. but that was just 2 tests with 2 different outcomes, so who knows.

Rabidbandit

I would still like to see results with a blown app.

300bhp/ton

I still think the power loss is due to lack off boost somewhere maybe the belts are slipping, did you adjust them at all?

IMO hot air would increase pressure, just like race tyres or a ballon. If it's hot the 'expand' and when cold 'contract'. The hot air may be less dense but the molecules (sp?) should be further apart.

v8hunter

iTrader: (2)

Just because the boost pressure went down on the gauge...that doesn't necessarily mean that the engine was flowing any less air. I have heard of that before with other supercharged engines which had their exhaust systems opened up and actually showed lower boost, but were making more power.

In order to know for sure if the manifold is crap...the motor should be retuned as FI applications are much more picky about what they like and don't like.

I'd put money that an unmodified wieand probably doesn't flow as good as a ls6 intake though.