High compression high RPM 7M-GE build

[Rollus]

I didn't meant copy, just doing similar with your own design. I don't know the english verb, for doing something "inspired"/"similar to" another thing.

I seen computer simulations about throttle design, barrel type was the best, butterfly type the most linear between the band, and slider type was on-off like Idle/WOT. I haev to search flow diagrams.

Do you have an idea about the cost of your assembly?

 

[Rollus]

Here are some interesting readings:

http://turbo124.com/forum/viewtopic.php?f=2&t=2992
http://www.ausrotary.com/viewtopic.php?f=3&t=217736&view=next
http://www.sohc.nl/index.php?action=engine

and my prefered: http://www.pistonheads.com/gassing/topic.asp?h=0&t=692680&d=10728.40185&nmt=

Just done quite a lot of work on this for my university dissertation. Designed and built a carbon fibre inlet manifold for a formula sae car and designed (but didn't have time to build) a linear stepper motor controlled telescopic inlet primary system which took a signal from the crank sensor and via a pic PLC controller, sent the appropriate pipe height to the motor which would adjust very fast indeed.

Anyhoo, as part of my research, I did a lot of work into throttle design and flow characteristics and I can safely say that a dual roller barrel system provides optimum flow. Camera shutter types cause some weird vorticies and are difficult to make strong enough, and butterflies create turbulance in the inlet...

What you want is something like this:

Following that, you want to get hold of a copy of this book: http://www.amazon.co.uk/Theory-Engi...=sr_1_1?ie=UTF8&s=books&qid=1242417460&sr=8-1

And this book: http://www.amazon.co.uk/INTERNAL-CO...=sr_1_2?ie=UTF8&s=books&qid=1242417569&sr=1-2

Ok they are a little pricey, but I'm sure you can get them somewhere cheaper on the net! I had to use the uni library copies... Both have some very good info on intake manifold design and theory though including variable length systems, exhaust gas recovery, dual plenum designs with balance valves, acoustic ramming, helmholtz resonators and all sorts... Interesting reading!

 

[TurboStreetCar]

Wow that dual roller barrel device looks like an impressive piece of hardware. Looks like right about 2-3000 dollars worth of CNC work with materials. :biglaugh:

 

[IndigoMKII]

Wow that dual roller barrel device looks like an impressive piece of hardware. Looks like right about 2-3000 dollars worth of CNC work with materials. :biglaugh:

I got some extra aluminum I might play with.

 

[andrew_mx83]

Thanks for those links rollus, some really good reading in there. I saw the word 'shaftless' which really got my brain ticking, and ive nearly worked out how to package it into my design
The double barrel design is nice. Ive not seen that before, only singles. I may do a barrel throttle one day, but the design hasnt come to me yet, and you cant rush these things... i understand what you meant, and im waiting for the inspiration! (Your English is very good btw)
As nosechunks said, its an expensive bit of hardware, and fairly complex. 2-3k for a set wouldnt be unreasonable at all. Strictly 5 axis work, holding tolerances in the tenths.

My goal is to have the cost of the assembly as close to AUD$1000 as possible, will see how it goes. Everytime ive priced up a conventional ITB setup for someone, by the time you get a manifold made, buy a set of throttles and trumpets, make linkages etc, 2000 disappears in no time at all. Im really trying to change that with this setup, and make it more affordable by making an assembly that bolts onto the stock lower manifold and has everything in 1 piece. I can post up or email a rendering once ive got the drawing a bit tidier if you're interested.

 

[1986.5supra_kid]

where has this thread been hiding?! It has been a very interesting read. look forward to the conclusion

 

[miekedmr]

That is cool... so cool that I could see myself [quite irresponsibly] spending thousands of dollars on dual roller barrel ITBs if anyone made them for 1/2JZs.

Very interesting thread as always.

 

[Rollus]

I'm still in 😁

 

[andrew_mx83]

And then all this stuff turned up...

Proper Japanese lpg injectors (not the solenoid type), good for 60hp/cyl. I hope to mount these in the stock rail.
Lpg converter/regulator to suit vapor injection. Rated at 320hp
Filters for both liquid & vapor phases
Rail pressure & temp sender

Aside from the tank, which is already installed, that should be the complete fuel system. Will order a megasquirt and all other the fruit next.

 

[andrew_mx83]

Ive done a bit of work on this but not enough
Getting ready to mock it all up and see if the new valve combo works. Pistons and rods are now in for the final time (hopefully!!!).

I recut the intake seats to suit the stock valves, also bought the margin thickness of the valve head down to get less protrusion past the head face. Id taken too much out of the exhaust seats to get a decent seal on the stock valves, so ive put the +1mm Ferrea stainless ones in. These have a nice big radius on the edge of the valve head, which should make it contact the piston much later (if at all)
From memory the intakes now sit 0.3mm proud of the deck and the exhausts 0.5mm, which is much better than when i first put the thing together.
I also smoothed off all the sharp edges in the chambers, ssr's and port dividers where it transitioned from cast to machined, since i needed to final wash the head (again!) anyway. Much happier with all that now.

Just have to set all the valve clearances now so i can clay up the pistons and put the head on for one final check. Fingers crossed it all clears so i can finish off the remaining loose ends and start driving this thing!!!!!


I also bought a gearbox for it, a freshly rebuilt R150
R154's go for crazy money here ($2k+) and are generally clapped out. Im sick of breaking W boxes and they arent exactly cheap these days either.
The R150 is essentially the same box but with shorter ratios. And no supra tax.


oh, lastly.... 4 valve FTW!

 

[Aleo24]

Awesome work, got to see a video of your customers N/A 7m on facebook and can't wait to see this one in action.

 

[SeeUSmile]

ohh nice ^^ got a link aleo?

 

[Aleo24]

Its on the A70 Supras Australia facebook group. Was a month or so ago.

 

[Koenigturbo]

I think it will be really fast. Kinda wondering if it will be laggy in the lower R.P.M range? Should be fine, I spent five hundred bucks porting my heads. and Like you said forty hours of die grinding. Th exhaust note should be crispy, just the way I like it.

 

[atmperformance]

I didn't meant copy, just doing similar with your own design. I don't know the english verb, for doing something "inspired"/"similar to" another thing.

I seen computer simulations about throttle design, barrel type was the best, butterfly type the most linear between the band, and slider type was on-off like Idle/WOT. I haev to search flow diagrams.

Do you have an idea about the cost of your assembly?

inspired, motivated, influenced, moved, or roused all work, probably influenced works best for your situation. (i teach English to both Japanese and Brazilian exchange students)

 

[andrew_mx83]

Yeah the supra motor came up real nice. It is what i would call my "hot street" motor with 268 cams and mid 11:1 CR, springs, oil mods, 0.40 over, balanced, blueprinted etc, new everything. It is a great combo and drives really well on both street and track. Extremely responsive, happy to lug up hills at 30mph in 5th and excellent power from 4000 - 7500rpm. Can be a handful in the wet.

I have made some compromises with this current motor im building, from being an all out high rpm motor as it is going in my daily and i want some driveability out of it. Ive gone for the heavy 7m crank rather than my preferred 6m one, relatively heavy clutch/fly and probably more compression than is really necessary. It still has the breathing and hardware to hold together at high rpm but im hoping these few touches will make it less of a pig to drive down low. Essentially once it is built and run in i will play with cam overlap and timing until im happy with how it drives.
In an ideal world, id like it to drive as well as the 268 cammed engines to that 4k mark, and then turn into a wild animal once the 280 cams wake up and hopefully pull hard to the high 8k area.


Looks like the supra guy has posted up a new video. We are running a megasquirt on this one (which is a first) so no AFM and no dizzy. Having troubles with it leaning out over 4000rpm but very healthy up til then. At 4000 it is already making more power than a stock one does at 6000, and the cams have barely woken up. We will set the redline at 8000rpm once it is tuned properly.
https://www.youtube.com/watch?v=C3vRZk-2zOk

 

[Grandavi]

I'm not a mechanic, but I'm wondering, at 8000 RPM, with the compression already quite high, any concerns with lifting the head? I've seen some heads that crack around the exhaust side where the head bolts go. Was just my first thought when I read the 8000 rpm redline. second thought was bearing survival. Glad it's you instead of me because I don't understand the entire engineering dynamic for this. If successful, the car will be a monster at those RPM.

Very impressive work so far. Wondering if anyone has done anything even remotely similar. Wish I could run mine on LPG... Lol. It's a bit over half the gas price.

 

[Rollus]

I'm not a mechanic either and won't answer instead of andrew_mx83.

AFAIC, I've gone with 9.5:1 on my 7MGTE, and here is what I did with my head: http://supra-mk3-rr.blogspot.com/p/technique-supra-mk3.html (in french, but you have a translate tool in the left panel of my site).

Hopefully, it will prevent it from lifting.

 

[TurboStreetCar]

I think being NA it will be subjected to much less temperature and pressure then even a mild (400hp) turbo motor. I dont think there is anything to worry about.

 

[andrew_mx83]

I spun the last motor in this car to 8000 with no bearing problems and i have another that regularly does 7700, both on stock rods + arps. You just have to keep enough oil upto the bearings and be anal during the blueprinting/assembly phases.
The problem with pushing this one towards 9k will be the stroke, piston speeds become horrendous too far over 8000. Im hoping the forged rods, upgraded pins and oil system mods will be enough to hold it together for short bursts. I still maintain that the 5m 85mm stroke is far more suited to sustained high revs but i had these pistons & rods on the shelf so decided to use those and will build the destroked race motor another day.

Previous motor started to have head lift issues over 12:1CR, but im fairly sure that head has gone soft now. The head used on the new build was my hardest in stock (120+) and i added arp insert washers to stop the alloy collapsing around the studs. Im also switching to a MHG now which is totally unnecessary on 99% of NA builds.