Porting intake manifold, larger tb vs. itb's

The 1UZFE EGR Delete Kit is available for sale here.
The one thing i haven't seen awnsered yet (think the question was asked though in some form)

to get the peak hp RPM higher up in the rev range the runners go shorter, but where did erol's 50mm diameter throttle valve come from?
we're obviously trying to make the effective diamater of the intake bigger to undo the boudary layer fenomenon making it smaller than it is is that the definitive reason?

the practical side of this.

is it the 50mm making it able to reach 500+hp CFM
and the short length of the runner decides where in the rev range peak HP comes?

from what i know/think (no expert by any means, just lots off theory and maths done)

I have the lower manifold but only a very small part of it, runners are now about 6cm long from plenum chamber into the head port. but the diameter of the part retained is stock,
what this will do is shift the peak rpm point upwards, and being able to flow a little better because the boudary layer effect increases dramticly in longer tubes. also the intake tract from the plenum to the valve has now only got 1 angle (from port to valve) instead of 3. in corners/angles flow choke is a very big factor.

How did you get the angle of entry into the head port that steep erol by welding up the lower part of the port? and have you been able to fully eliminate the curve/angle into the valve throat?


@ jibby, I hear you on the experts vs hobby man debate, but all of ou keep it nice please, here's one for you.
warning: "low cost tech approach DIY research and tune project)
get 2 pieces of 8mm alloy plate make those into intake manifold flanges, 8 peices of tube about 10cm long 40mm in diameter, or fabricate from sheet tapper from 40 to 45mm ID, 2 stes of hayabusa or R1 throttle bodies from ebay, mount everthing together and put it where your stock manifold now is. make an airbox to cover the intake trumpets, run a tube the size of you AFM/MAF outlet from the box towards that sensor leave you cone filter attached, and start to play with the length of the trumpets and if possible the length of the runners.

Very low cost, no need to inmediatly convert to programmable manegment, easily sold on if no succes. Nice learning curve and practical stuff like that beats calculting till you see purple while still not having put anything together.

I actually did this on my old 16v T-vis 4age in my striker once throttle response was through the roof compared to stock, and torque kept on about 1400rpm higher than stock, result extra BHP from the RPM. did require a little higher fuel presure but was controlled by the stock 4age ECU, I've never tried on MAP version but if a canister is used for vacuum I think it coulb be possible,

back to topic

Grtz Thomas (not scottish btw)
 
get 2 pieces of 8mm alloy plate make those into intake manifold flanges, 8 peices of tube about 10cm long 40mm in diameter, or fabricate from sheet tapper from 40 to 45mm ID, 2 stes of hayabusa or R1 throttle bodies from ebay, mount everthing together and put it where your stock manifold now is. make an airbox to cover the intake trumpets, run a tube the size of you AFM/MAF outlet from the box towards that sensor leave you cone filter attached, and start to play with the length of the trumpets and if possible the length of the runners


Striker, I am trying hard to picture what this looks like completed but am coming up just a little short with my limited imagination...:33: It sounds effecient though...Any pics of this intake scenerio by any chance?
 
i'm trying to remember, but couldn't find it. Did someone make 1,000hp with a 1uz in an ultima gtr, was he using an early engine with a stock/custom manifold or a later vvti? Justen, did you say that the powerband is the same even with FI on the stock manifold?
 
This is a great thread for me as I am just getting ready to fabricate a plenum with a front mounted Nissan throttle body. It seems as though the plenum volume needs to be in the order of 40-50% of the engine displacement. Even with twin turbos is this correct? I believe it is.
 
JustenGT8,

I know this is off-topic, but does relate to why i asked the original question. I agree with you on most all of these points, but i still like to discuss it. Everyone complains about weight distribution on an i-6 in small cars. What's strange to me, although logically it would seem i-6 cars would suck at handling, the best handling small cars i have been in are BMW's. Notorious for their handling and they are small cars with long i-6 engines, makes no sense logically, besides the chassis are designed for their engines. What about old z cars? Toyota 2000gt? So to me that is a case study which helps support the i-6 handling issue. Speaking of that what about position of a turbo in an i-6. It is going to be next the strut, while a turbo 1uz would have the turbo hanging in front of the engine bay in a bad spot to add weight. Turbo plumbing in a celica engine bay with 1uz, also no available turbo manifolds and i am not a fabricator= nightmare yes? I think there is a price difference in turboing the 2jz vs. 1uz, there are nice kits out their with all components and tubular manfolds for $1299 on clubna-t that people are loving. Also the cost of adapting 1uz to manual, very high. Also there are piggybacks know to work well on 2jz-ge, none on 1uz. These are major cost differences. Finally, what about a front-mid engine design, too much fabrication? Opps,also to note, someone on club na-t bolted in a 2jz w58 combo in a 79 and it fit so perfectly the w58 trans mount bolted right up to the original holes. He also noted that the suspension didn't drop any after the conversion from the heavy 20r which the engine i have, maybe the 18rg aussies' had was lighter?

UZ over 2J in that chassis mate.

UZ will provide better handling balance and mildly tweaked will provide more than enough hp with great torque.

If you do want to go FI eventaully then not much price difference in turboing a n/a UZ to and n/a 2J.

UZ also lends itself to a cheapish M90 SC setup for even better torque

UZ FTW in my book (and i love the 2J, but only in the right chassis)
 
i'm trying to remember, but couldn't find it. Did someone make 1,000hp with a 1uz in an ultima gtr, was he using an early engine with a stock/custom manifold or a later vvti? Justen, did you say that the powerband is the same even with FI on the stock manifold?

WDoherty - Yes majola (?) cranked out the big numbers but with a totally custom inlet.... and yes again, the powerband is the same no matter how much boost i screw in. Ffrom 6 to 17psi the dyno curve was the same across the rpm, just a higher hp at every point.

RE the inline 6. All my points stand....i've either done it, or a mate has so this isn't speculation. Drop me a pm if you want to discuss, or start another thread and i'll happily expand on my reasoning/experience.

andrew K - 1.5 times engine capacity is rule of thumb for plenum size.
 
respect, i'll start another thread later.

WDoherty - Yes majola (?) cranked out the big numbers but with a totally custom inlet.... and yes again, the powerband is the same no matter how much boost i screw in. Ffrom 6 to 17psi the dyno curve was the same across the rpm, just a higher hp at every point.

RE the inline 6. All my points stand....i've either done it, or a mate has so this isn't speculation. Drop me a pm if you want to discuss, or start another thread and i'll happily expand on my reasoning/experience.

andrew K - 1.5 times engine capacity is rule of thumb for plenum size.
 
Back to topic; it's awesome what your doing with the custom manifold, can't wait to see the results. If someone would produce a manifold, this could be a cost effective key to opening up one of the 1uz's worse limitations.
 

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keep in mind that even tho there is only one trottle body its really only being used by one cylinder at a time.

I completely understand that and always have, but still isn't one large throttle body where all the intake air needs to pass thru more restrictive then independant large TB's?...Jake, you claim there is really not a big difference between the two if both are setup to work effeciently.....Again, if that were the case and both are close to equal then why even bother with ITB's?...What's the point for all the trouble involved? Just for sound and a tiny bit more throttle response?
I may not be a pro, but even a novist can make logical sense out of that...

I am really trying to get to the roots and the possibities of ITB's vs. A larger single one throttle body setup...

Can any one give me a better reason to switch to ITB's rather then the one larger throttle body?
 
I also think about the BFI intake design where as the intake air flow is channeled and funelled directly into the single Throttle body... It's almost like ramming the air into the throttle body when the car is in motion... At idle the motor sucks in the intake air, and in motion it is somewhat being forced...

You don't see to many ITB's with "each individual intake air flow that is isolated" system like the BFI design.. Some designs I have seen come close though... Doesn't that have to considered when comparing the two for performance?
 
Striker,
Roof of port has been raised, cut out for injector has almost gone. Floor is std for the moment. Every time we change port/manifold dimensions I have to make a new manifold !

50mm is the size used on the 3ltr DFV's and the Judd.

Some theoretical velocity's, at 14.7psi atmospheric and 30 deg C.
Stock + ITB's at 6500 307bhp
Valve - 301, port - 310, runner - 218, TB - 177
Race at 7800 max torque 338lb/ft
Valve - 254, port - 293, runner - 262, TB - 212
Race at 8400 max power 534 bhp
Valve - 274, port - 315, runner - 282, TB - 229
Race at 9000 520bhp
Valve - 293, port - 338, runner - 303, TB - 245
20% larger port ?? at 9000
Valve - 293, port - 296, runner - 303, TB - 245

If the larger port will maintain the 333lb/ft we have at 8400 to 9000 we should have 570 bhp.

Jibbby,
We run a large tapered K&N filter in the airbox, the intake temp after the filter and at the ramtube is the same as ambient.
So far as ram pressure goes, you have to be going pretty quick. The data log is intake pressure down the straight. 8600 rpm is 160 mph. Ambient pressure was 100.4 kpa.
 
Has anyone changed the location of injectors ??
usually the higher rpm motor makes its power the further the injectors are away from head.. I'v seen them placed on the end of trumpets / ram tubes...
 
Jibbby,
We run a large tapered K&N filter in the airbox, the intake temp after the filter and at the ramtube is the same as ambient.
So far as ram pressure goes, you have to be going pretty quick. The data log is intake pressure down the straight. 8600 rpm is 160 mph. Ambient pressure was 100.4 kpa.

Thanks for the reply RMS (Erol) your a swell guy with grey hair and big ears...I'm sure the girls or wife love ya, because big ears usually means you got big ----... I remember your first post on this forum how can I forget... :beerchug: :beerchug: :beerchug:

I did figure you had to be going pretty fast to make any kind of difference.... It's all the little things you can do that start to add up that makes the car run more effecient when modifying from stock..... Like the basic intake designs before the throttle body..5-10hp or so is still 5-10hp......

I am done on this thread as there are two many topics going in each and every direction..I don't want to cause anymore confusion.....

I must say this thread really had me going for a while like no others in years past, it's actually been a long long time since I've actually been rattled on the forums..:banghead: . Congrats to ED and Jake for that as I didn't think it could be done. You guys did rattle me, you guys really made me feel like a rookie which I would like to think I am not..:ugh: Regardless of what you fellas think I do know the 1992 SC400/Soarer bumber to bumber and just like the back of my hand...I can fix or break down everything on the SC400, LS400, GS400 and then put it back together, no problem, except maybe a full transmission breakdown or something of that nature. I would really like to think I do bring something positive to this forum...... Now with that being said I say to you all farwell and good night...See you guys later....Much later....:smoker:
 
Ed if the result is Tiny, either you have a very well siezed stock TB or poorly seized ITB's Throttle response is normaly much better with correct ITBs

Erol thanx for the info, one Q as allways, since you haven't changed to portfloor I asume you still have the bend in it? sorry for sounding stupid but not sure what you guy's mean by port floor, terminology problem.

basicly are just the Runners and Throttle bodies in downdraft set-up
or is the whole intake tract from valve to throttlebodie including the port a downdraft idea? ie no bends like looking down an yamaha R1 intake tract from the trumpets down on the valves? thought that was impossible on these heads......


@ jibby, no helas no pictures of that set up at the moment loooong ago, but it's very simple, make an intake manifold that will take 8 hayabus or yamaha R1 ITB's, attach an airbox over the lot and run a big intake tube towards the airflowmeter that is in your 1uzfe now, and hey presto (if the ecu is as forgivving as a 4age AFM obd1 one)
you'll now have 8 ITB's on your 1uzfe running the stock ECU. can't get any cheaper than that and worked for me on the 4age.
look at the stock set-up of an 4age 20v silvertop, That's what I mean but then twice as big because of 8 cylinders.
the idea was you can play around with the intake lengths of the system to verify RMS' numbers yourself. the manifold doesn't decide how much torque comes, just when it comes, and therfore makes more power versus less low end torque, or vice versa. play around with the system till you're satisfied......
the parts aren't that expensive (a set of new good rear tyres will probably cost much more.)

Grtz Thomas
 
striker;82669 @ jibby said:
Thomas that sounds very promising and doable.... Question, did the ITB's you setup give you any kind of trouble over time?...Like adjusting, tweaking, cleaning, constant attention, etc.. How reliable were they for you compared to a single TB?.... You obviously had to dump the stock MAF system and convert to MAP also..Is that correct? You mentioned the airflow meter, so you got me wondering MAF?

I thought I was done with this thread but this last post really grabbed my attention... Seriously, Thomas (stiker) what gains did you notice with that setup that you did.. More info needed please? Would you do it again on your next 1uz-fe? What's your take overall about the ITB's?
 
Yep, you did this with the Stock ECU and MAF intact, and got good reads...WOW, I didn't think that was possible... Now that is easy and cheap and actually makes sense.. Really all you are doing is replacing the intake manifold and changing the one throttle body to eight while leaving everything the same.... Did you see big gains because with that setup as you still have to have all the intake air pass thru that little MAF body? Under full throttle I think maybe you would be ristricting air flow with the MAF and 8 ITB's, no?
 


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