building the 7a to become fte, comp. tech. build discuss Options

[playr158]

DISCLAIMER:if you wanna say 3s,4a,7ag or otherwise don't post...if you wanna talk trash dont' post if you have nothing technical to say don't post this is purely technical and for the information and technical discussion of the complete build of this motor to grow and people to learn and discuss

now on to the complete discussion

lets start off with the "weak issues" of the motor mechanically

1) the main thing most people hear is the rods are weak
what is the real potential of the rods? and our options for a solution?
what makes the rods the weak point. and the known option is forged rods from
pauter. but what makes them that much better/stronger? what kind of boost
can they handle

2) pistons. what kind of stress can they take, and the design flaws of them as stock? who has boost on them and what have you encountered as a result of using them. 4agze pistons are known to work as well what compression has been reached by swapping them into a stock 7afe and what boost can they handle in the 7afe? what was required to make them usuable?

3) rod and head bolts....are there any aftermarket options? would they be considered a weak point under a boosted application and at what point would they be an issue? what makes them a point of needed attention? and what would the advantage of changing them be?

4) cylinder wall....is this a potential weakness? how thick is it? what boost can it potential hold? what boost has been run on it? what about boring? whats the "safe point" and the results of boring be?

5) head design: YES IS ECONOMY but whats wrong with it? and what would hte potential downside to it be? how could you modify the head to be more sufficient?

NOW onto the other general features of the motor in relation to boost

lets start with
Electrical
1) MAP SENSOR:Definition: Refers to a manifold absolute pressure sensor, a variable resistor used to monitor the difference in pressure between the intake manifold at outside atmosphere.
the stock 1bar map sensor only sees -14.7 to 0 vaccum
it cannot read boost. and it reads 0-5 volts
what do we need to do to utilize this in our boosted application.
what bar sensor would be appropriate for each setup
a 2 bar map sensor (-14.7 - +14.7psi)
or even 2.5 bar?
or greater? what car can we get one from? manufacture? how would you adapt it or will it plug in?
SDS product (map sensor)
MAP Sensor 1 Bar Abs(for normally aspirated) $64
MAP Sensor 2 Bar Abs(up to 15 psi boost) $75
MAP Sensor 3 Bar Abs(up to 30 psi boost) $90


2) FUEL DELIVERY
A) INJECTORS: our stock injectors by no means will handle boost
so we do know that we need HIGH IMPEDANCE TOP FEED injectors. Is there another vehicle with the ability to share injectors with? or which manufactures are good for an aftermarket piece? how do you calculate what size injector would be useful? i found that RC has a useful formula to calculate:
In most cases Turbocharged engines will have a B.S.F.C. (
B.S.F.C is brake specific fuel consumption - How much fuel you are using per horsepower per hour) is .60 to .65 and as a industry standard 80% duty cycle is whre most injectors will "max out" so there for use the equation of
or if you want to start with the injector to find out what amount of crank HP they are good for in your motor use this formual:

~ RC SL9-550's fit 7afe

B) FUEL PUMP: the accepted transplant for a 7afe stock fuel pump is known to be a WALBRO 255lph pump (easily found on ebay or other online sites) or a Stock OEM 93-98 supra twin turbo fuel pump....anyother options?

C) FUEL PRESSURE: how do you control this with the turbo setup? what controls and devices are needed?

3) ENGINE CONTROL
a) STAND ALONE: this is the most able way to control your new turbo setup.. fully programable what will be the detailed benefits of using a stand alone? what does it control specifically? installation? tunning and programing? and which products are available?

b) piggy back: this uses your stock maps and "fools" your ecu...what are the benefits of this method? what does it control? what is a downside to using a piggy back? what products are available?

4) GAUGES: what can you see on your motor?
air/fuel, wideband o2, egt, oil pressure, oil temp, water temp, water pressure, fuel pressure, boost pressure, intake manifold pressure...what are the benefits of each one and what products are better then the other?

MECHANICAL

1) TURBO: which one is good for you? what manufacture is better (greddy, hks, turbonectics, garrett, dsm) what do the sizes mean what is prefered for the 7afe
and turbo maps?

2)WASTEGATE: internal and external? what do these do for you and which one is better? what options do each one offer you? how do they function?

3)Exhaust manifold:
2 options: first is your standard log stlye manifold while this is a decent design it is also not the greatest do to the unequal flow from each cylinder and if you decided to use an external wastegate issues would arise.
your second option is the HONDA B16/18 series turbo manifold....turbular in design and equal length tubing this design is more favorable to the log style of option 1....the only needed modification to get this piece to be ready for 7a usage is to cut off the exhaust flange on your 7afe OEM manifold and the b exhaust flange on the new then weld the 7a flange on the the b header

4)HEADGASKET: will a stock headgasket hold the boost? or will an aftermarket be needed? who makes one for the 7afe specifcally? and 4agze headgaskets can be used but will interferance be created? and who makes a good headgasket for the 4agze that we can use? what will a 82mm headgasket do on our 81mm 7afes?

5)valve train: will stock valves and valve seals be sufficient enough for a boosted 7afte application and to what psi can it be relable? are there stronger aftermarket options? what could be done to new stock valves to make them stronger?
5a)CAM SHAFT: the stock 7afe cams sufficient? to wat amount of power would they be benficial and when would they start to fall short? how would you know that the cams arn't performing to what you would need? will the JDM spec cam shaft help? whats the difference.. are aftermarket cams available for our 7afe? and can we modify our stock cams to be more boost beneficial? what would beed to be done?

6)cam gears: what do these do for us? can we work with them or will new ones be needed are aftermarket cam gears avail?....what would be the benefit or lose of using them?

7) head design: what can be done to help the head design to use it to our full benefit? port and polish? or what are our options? who can do this for us? ideal sizing or grade of modification to the head?

8) pistons: (doggy's findings)
Second - GZE pistons are full floating, wrist pin is floating in pin insert on GZE rods. I thought doing this the same on 7A rods, and making GZE pistons full floating on 7A rods.. But..7A pistons wrist pins are pressure fit to the rod, this means there is NO WRIST pin insert in rod, NO oil drain for wrist pin.If you wanna make GZE pistons full floating you have to rework 7A rod top end. This means you have to put the wrist pin insert and make oil drain on the of the rod.For making 7a rods with inserts, you would need to mashine the top end hole about 2 mm, then put the insert in and get it polished till the right diameter (i know im using not the right word with "polishing" but some guys will know what im talking about ). THis would weaken the rod, and the place there the wrist pin mounts, same would happen with oil drain hole cuz it would need to be driled at the top of the rod.... And weak rods and boost do not go together at all......So the only chance is left go pressure fit with the GZE pistons, and forget about reworking the 7A rods... you will have stronger pistons, but only one chance if detonation will apear, cuz only one place would float fully


i believe for now since i'm tired i will hold off here and leave this for discussion.....
please add to this discussion and be helpful to others.....please no trash, or talk of other motors or options.....strictly 7afe
AE58 C-160

This post has been edited by playr158: Jul 19, 2005 - 2:44 PM

[playr158]

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This post has been edited by playr158: Jul 19, 2005 - 2:21 PM