Project Thread LS 400 Single Turbo

[Fasteddie]

...what do you guys think, will give the best results for my setup ?
Cams or intake ?...and why ?
If it is NOT the intake, does this mean that SUPERCHARGED 1UZs with a different intake offcourse, will be limited by cams ?
Any supercharged dyno sheets available that do not have the "after 4500rpm drop in power" limitation ?....thx !

 

[cribbj]

Nearly all of us with screw or Roots superchargers are using either the Richwood or Bullet manifolds, or a home brewed version that replaces the restrictive OEM lower manifold. And our dyno curves don't have that characteristic falloff. But in thinking about it, nearly all of us are running different cams too. Hmmm, don't know which one worked better for the top end.

Super Runner might be the only one running a stock lower intake with his home brewed setup. It'll be interesting to see if his power curve falls off.

JustenGT8 was the first to notice this and comment on it here, so perhaps he'll jump in and add something. I'm pretty sure he'll say it's not the cams but the manifold that is the restriction.

 

[JustenGT8]

Jumping in

The cams are very mild for sure and at some stage will be a limiting factor for top end flow BUT from all the testing i've done and thr results of others it appears the lower intake manifold is a bigger influencer of the shape of the power graph.

Add boost and you make more power sure but the whole power (or torque) curve just moves up. To 'straighten' the curve out, go short runner intake manifold and big top end gains result.

Just changing cams with the stock lower part of the intake manifold in place does not result in as much change. From results of others running higher flow cams (even with ITB) but the stock lower half on the manifold in place the 'roll over' point for power/torque only moves a few hundred rpm. Swap out the lower intake manifold and my car has kept porducing increased power out to redline.

Of course, if budget allows do both. But in my view cams are wasted without scrapping the stock intake manifold 1st.

 

[XR8tt]

 

[Fasteddie]

Thx Justen!...intake is planned for end of April, together with a new dyno session....before that we will also have the Boostlogic auto trans in place.
So new session = intake + BL trans...will be fun to see what we get !

 

[Fasteddie]

Guys,

we installed the BL automatic. Now it really shows the short powerband that decreases rapidly after 4500 rpm.
We have a 3800 stall, so that restrictif manifold basically only allows a short power increase, and then it drops.

Anybody experienced similar results with a high stall and the 1UZ ?

 

[spf_lexus]

Short runner time? Your project is perfect for the before and after.

 

[Fasteddie]

True, we hope to produce the before & after results in about 4 weeks ...

 

[hungryforinfo]

What are thge intake runner options, just the 3uz one?

 

[Fasteddie]

custom made manifold

 

[XR8tt]

Is this in lower gears ?? Could just be engine revving before turbo hits any decent boost ?? Till there's some load on engine..
On a dyno this is often the case with high rpm converters..

 

[Fasteddie]

...with the 3800 stall the engine seems to "stall" at 5000rpm.....meaning: under full boost, the needle sticks to 5000rpm instead of somewhere around 3800...anyone familiar with this problem ?......does the built just slips past 3800 ???...

 

[cyberdiamond]

Thats normal if the converter was not spec'd for turbo engine.
Even if it was its hard to know how much torque you have until you have it running so its only a guess at best.

A converters stall speed is totally dependent on the torque that the engine is putting out.

 

[XR8tt]

Yep its over powering converter...
140 h.p then when turbo is spooled its a 500+ h.p torque monsta...

 

[Fasteddie]

...we make more then 600ft/lbs at 4500rpm, and at 5000rpm it is still very high...
The transmission is a Boostlogic built automatic with 3800rpm stall converter...which now stalls at 5000rpm...hmmmm.....

 

[Fasteddie]

...guys at Boostlogic suggested that a 3200 stall would be better...
The Lexus will be at the shop that will design and install a new intake manifold the whole coming week...we are aiming for 600rwhp all the way until redline, so no hassle with that power dropping after 4500rpm....
Will post pics of that progess soon ....
Anyone some info on the limit of the stock cams? (can they support this kind of power ?, they "look" to have a good duration/decent lift...)

 

[Fasteddie]

...some progress on the new manifold:

 

[JustenGT8]

Looking good mate...that's what i wanted to refine my prototype into, nice

 

[Fasteddie]

...more progress, lets hope we get this 1UZ to perform ....fingers crossed.....

 

[JustenGT8]

Looks great mate, nice work.

That should 'straighten' up the power curve and improve your top end out of sight