How restrictive is the stock 1UZ inlet manifold ?

[Fasteddie]

Guys,

now that we are building the 1UZ, we moved to shim under bucket with upgraded springs with the right lbs needed etc etc....so we dont expect "valve float" at high rpm....target rpm +/- 8000.
First we will try the stock cams and see what figures we get...
Now i am wondering if the stock inlet manifold can get us to 8000 rpm or maybe even 8500 ???....read somewhere that the stock runners are only good untill 6500...so what will happen at > 6500
What can we expect ?...anynone ?

 

[cribbj]

Not to hijack your thread or question, but what sort of seat and opening pressures are you running with your new springs?

The reason I ask is that our resident Lextreme engine builder, RMS, had reported he had seen 1UZ cam drive pins shearing with heavier valve springs. Might be something to think about if you're doubling or tripling the seat and opening pressures to avoid valve float. A sheared drive pin would make for a very bad day if your cams have enough lift that the engine is no longer non-interference.

I too converted to shim under bucket, but kept the stock springs, and it seemed to be OK up to 7000. Really wanted to take it higher, but our supercharger belt was already slipping bigtime.

 

[Arnout]

seat pressure 80 lbs. opening pressure 135 lbs

 

[JustenGT8]

No point trying for more than 6500rpm with the stock manifold....runners are too long and too small a diameter.

You need a short vetical runner design like the one i did or similar.

 

[Fasteddie]

Thx...are there any dyno sheets of reving past 6500 rpm with the stock inlet?....

 

[JustenGT8]

All my dyno runs, right up to 400rwkw, have the power curve nosing over around 5300-5500rpm

 

[ed_ma61]

bit of a correction there johnny, erol didnt blow a shear pin with heavier springs. infact the engine was a stock Tokyo taxi. blew a pin secondary to a push start backfire that either broke the pin directly with the shock load, or slipped a belt then tried to fire again out of sync. either that or the cam pulley retaining bolt failed. bit hard to tell what came first. either way nothing to do with springs whatsoever... perhaps another yankee-fact crisis averted?? lol

theres a long thread around discussing the possible issues with the manifold. if you plan to go big rpm/cfm youll need to build a new manifold. pushing sh1t uphill otherwise.

building the 1UZ...target rpm +/- 8000....First we will try the stock cams

what on earth make you think stock manifold and stock cams will want to go anywhere near 8-8500rpm?? nothing in the system would want to go that high, why try? a new manifold would get you say 1k over oem power band, then get the cams to suit. but stock + stock = zero gain

 

[Zuffen]

Ed,

A link to the thread you speak of would be most beneficial

 

[Fasteddie]

Thx for the info....

what on earth make you think stock manifold and stock cams will want to go anywhere near 8-8500rpm?? nothing in the system would want to go that high, why try? a new manifold would get you say 1k over oem power band, then get the cams to suit. but stock + stock = zero gain

...since we are making a built block with some nice internals that can handle 8-8.5k rpm we already know that the inlet will be restictive based on design and experience by others...same goes for the stock cams...
Unlike with the 2JZ there is no proven inlet manifold that we can order and everything will be fine...so in a way it is a "trail & error" situation (which i dont like as a customer...)....

 

[cribbj]

Ed, the communication I received from Erol indicated he was having drive pin problems with the high lift cams and stiffer springs in the race motor, not the totally stock Tokyo taxi motor.

There's a possibility I misinterpreted his email, but in any case, you can take your "Yankee fact crisis" aversion and stick it where the sun don't shine. :lmao:

 

[ed_ma61]

its not exactly an authoritative discussion, just some musings by smart people.

http://www.v-eight.com/tech_forum/viewtopic.php?f=4&t=268

john my friend, id suggest you clarify whether erol had an actual failure with the race setup, or rather had a failure on the tokyo taxi and is thus wary of a similar failure (and subsequent prophylactic management of) the race motor...

considering i was pushing the reynard when it went bang, im reasonably confident of the circumstances of the first (and only?) pin failure. more than happy to stand corrected tho.

as for 'yankee facts' - dont make me sift through the internet finding details of the masses of forum based automotive misinformation sprouted as gospel and embalmed as technical fact. ps - keep it clean, sarcasm is looked poorly upon

 

[ed_ma61]

in a way it is a "trail & error" situation (which i dont like as a customer...)....

not really. its not like this engine defies the laws of physics, just look and learn from similar engine development on other platforms... id ballpark 280-290deg adv duration, lift to suit your port flow, something like 280-320mm runners with a big tapering internal dia.

running the engine with stock cams and manifolds wont 'teach' you anything (other than it doesnt work) and wont give you much of a hint as to what 'would' work

 

[cribbj]

Ed, Erol's email cut & pasted:
"...another problem that has reared it's ugly head and you need to look at is the camshaft drive gear/camshaft interface. With our current cams, 330 deg - .440" lift, the std drive pin is totally inadequate. We have had the retaining bolt 'back off' and it was tensioned to 80 lb/ft. We fitted 2 additional 5mm drive pins about .250" deep into the cams and still had problems with fretting. The pins rocked in the cam and gear creating oval holes. We now have 2 pins .5" into the cams and ALL the way through the gear.
The engine has done around 600 race miles with this mod and seems to be OK"

In a previous email related to this one we were discussing the heavier Performance springs that he was running at the time, and we both agreed that a lighter spring was warranted.

Ed, misinformation on the Internet knows no nationalities or boundaries, and for you to keep using that term "Yankee fact crisis" is offensive to many of us.

Keep your sarcasm to yourself, and I'll keep it clean on my side.

Sorry for this unwanted diversion of a good thread; I'm done.

 

[ed_ma61]

nice... some accurate technical clarification, somewhat different to the first 'statement' that "1UZ cam drive pins shear with heavier valve springs"

you wonder why i jump on my soapbox... lol anyways, im also done, crisis averted

better solution to drive pin problems - get a vvti engine
also gets you around the manifold velocity issues. 200rwkw out of stocky mcstock vvti engine with aftermarket management. anyways, i digress (again)... do the math (its not that hard) and prototype a manifold to suit your engine. seriously, 8-8.5k is going to need a full system remake if you want it to work and not be disapointingly underperforming

 

[XR8tt]

All my dyno runs, right up to 400rwkw, have the power curve nosing over around 5300-5500rpm

I would expect that with std cams and springs..
Its the total induction package.. I doubt its the length ?? More the restriction and or angle as inlet enters head ??
To a point this would depend if N/A or forced engine??
400 rwkw is around 15 Lb and thats about the limit of std springs..
Any modified engine would dowel the cam better than std if he knew what he was doing.. Though its easy to see now....
Exactly how much extra power is made with VVT heads etc on forced induction?? Over 1UZ heads.. In both cases I would they would need to be modified ?? Depending on expected power levels??
I'd like to see a well sorted forced motor with cams, springs etc with ported std inlet and see the power gains at 18 to 25 Lb...

 

[ed_ma61]

its not so much the length, its the dia, and subsequent effect of length at that dia, the effect of the boundary layer as the velocity increases, and the flow choke point

suggest reading the thread linked above. lots of questions, a few answers, ideas to play with.

 

[Fasteddie]

Exactly how much extra power is made with VVT heads etc on forced induction?? Over 1UZ heads..

That's an interesting question...but again, not enough data to safely predict what will happen...
I know of one:

600 rwhp and 600 rw ft/lbs...

All my dyno runs, right up to 400rwkw, have the power curve nosing over around 5300-5500rpm

We will take your dyno results as a ballpark estimate for sure...just wondering if it can be topped in stock form...possible ???

 

[XR8tt]

Have a look at the 1UZ inlet? They tapper down around manifold / head gasket.. I assume to increase torque ?? To pull heavy vehicles..
With this restriction, it would cause resonance big time..

The new XR6T has a MUCH shorter inlet manifold..
On most converted turbo engines you gain better power etc by shortening inlet by about 20% and making plenum much bigger...
Unless its an all [most] out race engine like the 4AGE 20 valve etc..
Though this is over kill with plenum size on 4Ltr 6 you cannot argue 11.2 @ 127 mph with std engine..

 

[Fasteddie]

...so any opinion on how to make more then 400 rwkw with the stock 1UZ ?...(pump 98 gas, built block with ported heads, upgraded springs, T88-34d single Turbo..)...

 

[JustenGT8]

You have pretty much what you need and even with the stock manifold you will make over 400rwkw.....just that the peak hp will be around that 5300-5500rpm. If you can extend the torque band then you will obviously make more hp.

The other guy with the T88 on here has done a pretty good inlet so a basis for you to have your own made.