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Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Thu Feb 06, 2020 4:29 pm
by yabaiani
I had a dumb question, but what are the steps/things I would need in order to take my bluetop motor (JDM MAP 16v) and add ITBs on it. I would love to know if I need new injectors, most likely a piggyback ECU (which one that works best for the the JDM motor), should I get a vacuum block, etc

Any help here would be great.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Fri Feb 07, 2020 8:26 am
by aukword1
You will definitely need either a standalone ECU or a piggyback like an hks fcon or something. You can run a vacuum line from each TB from the adapter plate to a vacuum block if you want but it's not absolutely necessary. Instead, you can tune the fuel map via throttle position and not MAP. Really up to you. I am running a vacuum block and am tuned via TP just for the hell of it. You dont need to upgrade the injectors unless you want to. So basically you will need an adapter plate, ITB's, ECU and a tune.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Fri Feb 07, 2020 12:06 pm
by yabaiani
aukword1 wrote:You will definitely need either a standalone ECU or a piggyback like an hks fcon or something. You can run a vacuum line from each TB from the adapter plate to a vacuum block if you want but it's not absolutely necessary. Instead, you can tune the fuel map via throttle position and not MAP. Really up to you. I am running a vacuum block and am tuned via TP just for the hell of it. You dont need to upgrade the injectors unless you want to. So basically you will need an adapter plate, ITB's, ECU and a tune.


Would you recommend the Haltech (https://shop.battlegarage-rs.com/produc ... dalone-ecu) or a simpler Greddy eManage Ultimate? I’ve always heard the MAP sensor causes trouble (or maybe just the fact that it’s a JDM car) with these standalone or piggyback ECUs

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Fri Feb 07, 2020 1:51 pm
by jondee86
To save a bit of typing I will copy and paste something I wrote to a guy on another
forum who was asking much the same question...

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The primary issue with putting ITB's on an otherwise stock single throttle 16V
engine is that opening the throttles with ITB's introduces a LOT more air into
the engine compared to a single throttle. On an aftermarket ECU you can adjust
the fuel map and acceleration enrichment to add a LOT more fuel at lower rpm's
when you open the throttles. The factory ECU can't do this, so you get a lean
condition (stumble) when opening the throttles quickly followed by an over rich
condition as the MAP reading goes high before the engine revs build up.

Higher up the rev range the situation is not so bad as the amount of air going into
the engine is not so different between a single throttle and ITB's. But the fuel map
will not be optimum at any rpm. In other words, it will run but may not run as well
as a single throttle engine.

The second reason is to do with idle air. On an AE101 or AE111 ALL the idle air
is introduced via the ISCV. This is a rotary solenoid valve driven by a PWM signal
from the ECU. On the stock TVIS engine extra idle air for startup is handled by the
auxiliary air valve under the throttle body. Warm idle is set by the idle bypass screw

Whe converting to ITB's and using an aftermarket ECU it is usual to either use the
ST/BT factory ISCV or a Bosch ISCV and drive it with two PWM capable outputs
from the ECU. Ideally, the idle air should be introduced equally into all four of the
intake runners.

The vast majority of ITB conversions are tuned using alpha-numeric (TPS tuning)
rather than speed-density (MAP tuning). This is because with ITB's the manifold
absolute pressure reading will hit atmospheric with a very small throttle opening.
However, single throttle engines are invariably tuned using a MAP sensor or airflow
measuring device for the load input.

When used with ITB's a MAP sensor has good definition at small throttle openings,
but poor definition at larger openings as once the MAP is at atmospheric opening
the throttle further has no affect on fueling. The TPS has poor definition at low
opening but much better definition at large openings as the ECU will increase fuel
according to the throttle opening. .
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As said above, if you want your engine to run well with ITb's you should look at an
aftermarket ECU like the Haltech so that you have full control over your fuel and
ignition maps, and you will also have the ability to control a PWM idle air valve.

Image
Image

This is a pic of the setup I had running on a smallport engine. This ran with the
factory ISCV from a 20V silvertop. Although it was a TPS tune my ECU used a MAP
signal input as part of it's fueling calculations, so you can see a small vacuum
accumulator hooked up to each inlet runner. I used the smallest available tubes
to dampen the pressure fluctuations and get a stable MAP signal.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 08, 2020 7:08 am
by yabaiani
jondee86 wrote:To save a bit of typing I will copy and paste something I wrote to a guy on another
forum who was asking much the same question...

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The primary issue with putting ITB's on an otherwise stock single throttle 16V
engine is that opening the throttles with ITB's introduces a LOT more air into
the engine compared to a single throttle. On an aftermarket ECU you can adjust
the fuel map and acceleration enrichment to add a LOT more fuel at lower rpm's
when you open the throttles. The factory ECU can't do this, so you get a lean
condition (stumble) when opening the throttles quickly followed by an over rich
condition as the MAP reading goes high before the engine revs build up.

Higher up the rev range the situation is not so bad as the amount of air going into
the engine is not so different between a single throttle and ITB's. But the fuel map
will not be optimum at any rpm. In other words, it will run but may not run as well
as a single throttle engine.

The second reason is to do with idle air. On an AE101 or AE111 ALL the idle air
is introduced via the ISCV. This is a rotary solenoid valve driven by a PWM signal
from the ECU. On the stock TVIS engine extra idle air for startup is handled by the
auxiliary air valve under the throttle body. Warm idle is set by the idle bypass screw

Whe converting to ITB's and using an aftermarket ECU it is usual to either use the
ST/BT factory ISCV or a Bosch ISCV and drive it with two PWM capable outputs
from the ECU. Ideally, the idle air should be introduced equally into all four of the
intake runners.

The vast majority of ITB conversions are tuned using alpha-numeric (TPS tuning)
rather than speed-density (MAP tuning). This is because with ITB's the manifold
absolute pressure reading will hit atmospheric with a very small throttle opening.
However, single throttle engines are invariably tuned using a MAP sensor or airflow
measuring device for the load input.

When used with ITB's a MAP sensor has good definition at small throttle openings,
but poor definition at larger openings as once the MAP is at atmospheric opening
the throttle further has no affect on fueling. The TPS has poor definition at low
opening but much better definition at large openings as the ECU will increase fuel
according to the throttle opening. .
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As said above, if you want your engine to run well with ITb's you should look at an
aftermarket ECU like the Haltech so that you have full control over your fuel and
ignition maps, and you will also have the ability to control a PWM idle air valve.

https://i.imgur.com/Gf9GBya.jpg
https://i.imgur.com/mVMVInK.jpg

This is a pic of the setup I had running on a smallport engine. This ran with the
factory ISCV from a 20V silvertop. Although it was a TPS tune my ECU used a MAP
signal input as part of it's fueling calculations, so you can see a small vacuum
accumulator hooked up to each inlet runner. I used the smallest available tubes
to dampen the pressure fluctuations and get a stable MAP signal.

Cheers... jondee86



Would you ever consider getting the TODA Kit if money wasn’t an issue? https://www.toda-racing.co.jp/en/produc ... n/4ag.html

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 08, 2020 5:25 pm
by jondee86
If money was no object then I would have had these...

Image

... and a forged engine with big cams running on ethanol :D TODA stuff is nice but
I like the idea of the throttles and injection being further outboard and the one-piece
throttlebody and manifold.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 08, 2020 7:14 pm
by yabaiani
jondee86 wrote:If money was no object then I would have had these...

https://i.imgur.com/RlM2sql.jpg

... and a forged engine with big cams running on ethanol :D TODA stuff is nice but
I like the idea of the throttles and injection being further outboard and the one-piece
throttlebody and manifold.

Cheers... jondee86



What is that one? Details?

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 08, 2020 8:43 pm
by jondee86
TWM now BORLA... smallport only...
https://www.borlainduction.com/2000-series.html#200040
I don't know much about them as after looking around I decided to make my own
manifold. Intake theory says you design for a certain length from the open end of
the bellmouth to the valve head... length depends on a number of factors. You can
find "rule of thumb" calculators on the internet.

The size (diameter at the throttle plate) of the throttlebody is critical to performance
and driveability. Too big and the engine struggles to idle but will make best power
high in the rpm range. Too small and bottom end response will be better, but top
end power may be restricted. It's all about keeping intake velocity high if you want
good driveability and sharp response off idle.

My research indicated that 38mm was the ideal size for what I wanted to achieve so
I used the 42mm ST ITB's and made custom "chokes" to reduce the intake to 38mm.
Might have cost me a bit of topend but paid dividends in torque and low end response.
That's what you want for a street driven car.

Jenvey also make a kit...

Image

So plenty of choices if you look around :)

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sun Feb 09, 2020 3:05 pm
by yabaiani
jondee86 wrote:TWM now BORLA... smallport only...
https://www.borlainduction.com/2000-series.html#200040
I don't know much about them as after looking around I decided to make my own
manifold. Intake theory says you design for a certain length from the open end of
the bellmouth to the valve head... length depends on a number of factors. You can
find "rule of thumb" calculators on the internet.

The size (diameter at the throttle plate) of the throttlebody is critical to performance
and driveability. Too big and the engine struggles to idle but will make best power
high in the rpm range. Too small and bottom end response will be better, but top
end power may be restricted. It's all about keeping intake velocity high if you want
good driveability and sharp response off idle.

My research indicated that 38mm was the ideal size for what I wanted to achieve so
I used the 42mm ST ITB's and made custom "chokes" to reduce the intake to 38mm.
Might have cost me a bit of topend but paid dividends in torque and low end response.
That's what you want for a street driven car.

Jenvey also make a kit...

https://i.imgur.com/N3SegM6.png

So plenty of choices if you look around :)

Cheers... jondee86



I reached out to Jenvey since they make a big port kit, but it says coming soon so not sure there...

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sun Feb 09, 2020 7:45 pm
by jondee86
You want state of the art ? This is state of the art...

Image
Image

https://www.mrpltd.co.nz/product/mrp-4age-billet-race-individual-throttle-bodies/

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Mon Feb 10, 2020 4:32 pm
by yabaiani


Super clean. Reached out to Barry from their and super nice guy. So I am now debating between the Jenvey kit or the one below...the one below though is almost $5000 shipped here with all the extras + ECU...

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Mon Feb 10, 2020 5:40 pm
by Jayrdee
I'm glad this thread came up because I had a similar question about the MAP thing, but you all already answered it. I wasn't planning on going ITBs anytime soon, but I couldn't pass up a good deal on some silvertop throttle bodies! I still need to buy an adapter plate, stacks, and ECU. Most likely going to try and do the DIY Megasquirt route but stick with the stock ignition system.

https://www.diyautotune.com/support/tec ... 2-article/

yabaiani, definitely keep us posted on progress! I know I'll be paying attention. Its nice to read an ITB thread that isn't 20 bajillion years old Lol.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Mon Feb 10, 2020 6:15 pm
by yabaiani
Jayrdee wrote:I'm glad this thread came up because I had a similar question about the MAP thing, but you all already answered it. I wasn't planning on going ITBs anytime soon, but I couldn't pass up a good deal on some silvertop throttle bodies! I still need to buy an adapter plate, stacks, and ECU. Most likely going to try and do the DIY Megasquirt route but stick with the stock ignition system.

https://www.diyautotune.com/support/tec ... 2-article/

yabaiani, definitely keep us posted on progress! I know I'll be paying attention. Its nice to read an ITB thread that isn't 20 bajillion years old Lol.


Definitely will...I am just debating between Jenvey and MRP ITB Kit...price is very different so just thinking it through. :)

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Mon Feb 10, 2020 9:34 pm
by jondee86
Just checking that you are doing the currency conversion right...
NZ$5000 = US$3150 or thereabouts. And if Barry's (MRP) price includes GST
to can take that off anything exported from NZ.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Mon Feb 10, 2020 10:26 pm
by jondee86
Jayrdee wrote:... definitely keep us posted on progress! I know I'll be paying attention.

The thing to keep in mind is that the amount of power that an engine can produce
is directly related to the amount of air that you can get into the cylinders. Changing
the induction system from a single TB to ITB's has very little (if any) effect on the
amount of air that enters the engine. Fuel needs air to burn and if you want to burn
more fuel to make a bigger bang, you need more air.

Factory single TB intake manifolds have runners designed to smooth and settle
airflow after it has passed the throttle plate. This is good for low and midrange power
which is where most of our driving takes place. ITB's with short intake runners gain
better throttle response due to the small volume of air between the throttle plates
and the cylinders, but lose the benefit of smooth airflow. Longer trumpets help by
tuning the total length of the intake to get some "ram" effect to help fill the cylinders.

What thia all boils down to is that your ITB setup has to be carefully thought out with
components chosen to maintain good intake velocity and cylinder filling in the rpm
range where you will be driving most of the time. Don't oversize the throttles, use a
manifold that has good flow characteristics and aim for a total intake length from the
end of the bellmouth to the valve head that is close to a helpful resonant frequency :)

Then, look at what other modifications you will make to take advantage of your new
intake setup. A decent exhaust to improve cylinder scavenging. Some head porting
to improve airflow into the engine. Increase the compression ratio. ARP bolts. Light
flywheel. Better have some forged rods. Cams with more lift and duration. Vernier
cam wheels. Upgraded valve springs. An aftermarket ECU for tuning fuel and ignition,
and some instrumentation for keeping it all safe.

All your mods need to be seen as part of a total package. If they work in harmony
with each other, the end result will be greater than the sum of the parts. Get it wrong
and you will be left scratching your head and wondering why you dropped 5hp from
stock when you get to the dyno.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Tue Feb 11, 2020 9:26 am
by Jayrdee
jondee86 wrote:
Jayrdee wrote:... definitely keep us posted on progress! I know I'll be paying attention.

The thing to keep in mind is that the amount of power that an engine can produce
is directly related to the amount of air that you can get into the cylinders. Changing
the induction system from a single TB to ITB's has very little (if any) effect on the
amount of air that enters the engine. Fuel needs air to burn and if you want to burn
more fuel to make a bigger bang, you need more air.


Oh yeah, for sure. Thats the reason why going ITBs isn't on my radar anytime soon. My motor is totally stock so I know I won't gain anything ...

... except for cool engine noise 8-) 8-) :lol:

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Tue Feb 11, 2020 10:47 am
by yabaiani
jondee86 wrote:Just checking that you are doing the currency conversion right...
NZ$5000 = US$3150 or thereabouts. And if Barry's (MRP) price includes GST
to can take that off anything exported from NZ.

Cheers... jondee86



I added Coil on Plugs (1NZ) conversion kit, fuel injectors, Link ECU + the full loom, and the fuel pressure regulator.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Tue Feb 11, 2020 10:43 pm
by Nick94tt
Following as well. I'm with others as to wondering what else will be in the motor when it's all said and done (compression/cams/valvetrain/porting...) The noises are epic if you can get a reliable setup ironed out. I do wonder about just swapping in a 20 valve depending on the end goals.

On the ECU note - find a tuner you trust first, then go with a widely supported ecu they're familiar with. Potentially save a ton of time and money. Ie - if your local guys only do Haltech and AEM regularly, consider one of those. Won't do a ton of good if they have to learn from the ground up on a new system. (Or aren't willing to, odd as that may seem.)

Pariah time... :D

K24 with a stock ecu (or hondata/aftermarket), trans adapter for a decent rwd box, and a custom driveshaft... Weights are similar, power is not. :lol:

If I ever ventured beyond something simple like a gze bottom end and a few pounds of boost, that'd be it. Parts availability and power potential - even a stock k24 would be long term fun in a corolla but sheer stupidity is a set of 1000+cc injectors and a turbo away.

Added bonus points for pissing off a ton of purists. :lol:

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Tue Feb 11, 2020 11:03 pm
by jondee86
I added Coil on Plugs (1NZ) conversion kit, fuel injectors, Link ECU
+ the full loom, and the fuel pressure regulator.

Well you can still make a tidy installation using less expensive components. If you
leave the injectors in the head you can re-use the factory injectors, fuel rail and
fuel pressure regulator. Get a nice ITB adaptor plate and some trumpets from SQ
Engineering, some ST throttles and a Haltech ECU and you are almost done.

SQ Eng also do a nice COP conversion plate and you can buy new aftermarket
1NZ coils for not much money on Ebay. Battle Garage can get you all the SQ Eng
stuff and they do Haltech as well.

I have nothing against buying high quality/high priced components if that's what
it takes to achieve the results I am looking for. However, if I can reach my goal
with OEM or lower priced componets, then I will use them and spend the money
I save towards other improvements. Put it this way... if you are building a race
car and want to be a winner, buy the best you can afford.

But if you are building a road car to use as a daily and have a bit of weekend fun,
then (IMHO) building to race spec is total overkill. OEM with a few basic bolt-ons
will keep you grinning. In the end it's your car and your decision, and the only one
who needs to be happy when when the installation is complete.... IS YOU :D

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 5:14 am
by yabaiani
jondee86 wrote:
I added Coil on Plugs (1NZ) conversion kit, fuel injectors, Link ECU
+ the full loom, and the fuel pressure regulator.

Well you can still make a tidy installation using less expensive components. If you
leave the injectors in the head you can re-use the factory injectors, fuel rail and
fuel pressure regulator. Get a nice ITB adaptor plate and some trumpets from SQ
Engineering, some ST throttles and a Haltech ECU and you are almost done.

SQ Eng also do a nice COP conversion plate and you can buy new aftermarket
1NZ coils for not much money on Ebay. Battle Garage can get you all the SQ Eng
stuff and they do Haltech as well.

I have nothing against buying high quality/high priced components if that's what
it takes to achieve the results I am looking for. However, if I can reach my goal
with OEM or lower priced componets, then I will use them and spend the money
I save towards other improvements. Put it this way... if you are building a race
car and want to be a winner, buy the best you can afford.

But if you are building a road car to use as a daily and have a bit of weekend fun,
then (IMHO) building to race spec is total overkill. OEM with a few basic bolt-ons
will keep you grinning. In the end it's your car and your decision, and the only one
who needs to be happy when when the installation is complete.... IS YOU :D

Cheers... jondee86


Let me go ahead and update everyone on the parts and build on what I decided to do. I am:

* Rebuilding motor with higher compression, new forged pistons, rods, valve springs, retainers, etc
* new Tomei Poncams
* Toda cam gears
* Toda timing belt
* MRP ITB Kit w/ new injectors, fuel pressure regulator, vacuum block, etc (https://www.mrpltd.co.nz/product/mrp-4a ... le-bodies/)
* Fujitsubo super EX headers
* Fujitsubo legalis-R exhaust
* standalone ECU and new wiring harness

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 1:15 pm
by jondee86
This is going to be epic :) See if MRP can supply a filter plate for the ITB's as
you do not want to risk running with open throttles on the road and you need
something like this...

Image

And don't forget the head work you need to get maximum airflow and take full
advantage of the new intake and exhaust. I'm sure that Oldeskewltoy would be
happy to help you with that.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 2:49 pm
by Nick94tt
jondee86 wrote:And don't forget the head work you need to get maximum airflow and take full
advantage of the new intake and exhaust. I'm sure that Oldeskewltoy would be
happy to help you with that.


Truth. Literally about the only thing left possible. :lol:

I'd consider hitting him (or your head guy if you already have one) up about cam choices as well - might be a better match for the desired powerband/port work, especially with a standalone - since the poncams are meant for max gains on a stock ecu car.

Should be an absolute screamer.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 3:01 pm
by yabaiani
Nick94tt wrote:
jondee86 wrote:And don't forget the head work you need to get maximum airflow and take full
advantage of the new intake and exhaust. I'm sure that Oldeskewltoy would be
happy to help you with that.


Truth. Literally about the only thing left possible. :lol:

I'd consider hitting him (or your head guy if you already have one) up about cam choices as well - might be a better match for the desired powerband/port work, especially with a standalone - since the poncams are meant for max gains on a stock ecu car.

Should be an absolute screamer.


I am absolutely doing the headwork right now too, no worries. :)

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 3:37 pm
by jondee86
Nick94tt wrote:I'd consider hitting him (or your head guy if you already have one) up about cam choices
as well - might be a better match for the desired powerband/port work, especially with
a standalone - since the poncams are meant for max gains on a stock ecu car.

This ^^^^. Depending on what compression you are planning to run, you may get a better
result with more aggressive cams.

The CamShop https://www.kelfordcams.com/nz/camshaft ... /4a-ge-16v have
some strong street/strip cams and you can get them thru MRP if that's convenient. With
what you are building these should work and give you a mean idle :)

193-B Camshaft Set 284/278 Degrees advertised duration. 9.20mm/8.50mm lift.

Ask Barry as he has vast experience with building 4AGE engines and can probably give
you a recommendation.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 3:44 pm
by Nick94tt
I'm pretty stoked. High compression screamer on E85 will make some sexy noises. :D

We don't have ready access to corn juice here yet. :cry: Subsidized race gas is a winner.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 7:03 pm
by yabaiani
jondee86 wrote:
Nick94tt wrote:I'd consider hitting him (or your head guy if you already have one) up about cam choices
as well - might be a better match for the desired powerband/port work, especially with
a standalone - since the poncams are meant for max gains on a stock ecu car.

This ^^^^. Depending on what compression you are planning to run, you may get a better
result with more aggressive cams.

The CamShop https://www.kelfordcams.com/nz/camshaft ... /4a-ge-16v have
some strong street/strip cams and you can get them thru MRP if that's convenient. With
what you are building these should work and give you a mean idle :)

193-B Camshaft Set 284/278 Degrees advertised duration. 9.20mm/8.50mm lift.

Ask Barry as he has vast experience with building 4AGE engines and can probably give
you a recommendation.

Cheers... jondee86


Got it, will do.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sat Feb 15, 2020 7:49 pm
by yabaiani
Random note...does anyone know of a good set of pistons and rods (not from MRP)? My machine shop said they would look, and I look at CP and only found pistons, not rods. Went to Brian Crower and found Rods. Don’t know if anyone makes both.

Arias just makes pistons...

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sun Feb 16, 2020 1:29 am
by jondee86
Well there is this... http://www.tomeiusa.com/?p=2326
And there is this... http://www.tomeiusa.com/?p=2321
Their website is a bit incoherent, so you would need to check that these
are actually currently available, and that they can do rods to suit the 40mm
diameter big end journals on the 3-rib crank.

Cheers... jondee86

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sun Feb 16, 2020 1:30 pm
by Nick94tt
Folks have been mixing standard setup parts for a long while. Usually just a matter of picking what you're comfortable with/can afford. Carillo's been doing rods forever, same as JE and Arias do pistons... Just a matter of making sure they're all sized appropriately. (Pin bores/locations/correct ring sizing/etc - engine builder standard practices)

Think of it like building a PC from scratch. End goals vs budget, then find the best parts you can that fit together and function. Might have an AMD CPU but you'll certainly have differing RAM and video card brands.

Crower does make a matched set of pistons and rods - they just also come with a new stroker crankshaft and a big price tag. :lol:

So long as the internals are rated for what you're planning on doing, all should be fine.

Remember to give your engine guy the entire assembly for balancing - clutch/flywheel/rotating assembly. (Assuming they're equipped to go that far) Matters more for high rpm screamers than overbuilt lower rpm boosted setups.

Re: Newb question on how to guide for ITBs on JDM 4AG Bluetop w/ MAP

Posted: Sun Feb 16, 2020 2:07 pm
by oldeskewltoy
Sorry this is my first appearance... I typically avoid ITB threads... they aren't often needed(my 140+ whp smallport runs just fine on a single T/B), and if not done correctly can and often does cause operational issues do to poor set-up (mechanical, as well as from a management POV)

yabaiani wrote:
I am absolutely doing the headwork right now too, no worries. :)


would love to see your work.......


yabaiani wrote:
Let me go ahead and update everyone on the parts and build on what I decided to do. I am:

* Rebuilding motor with higher compression, new forged pistons, rods, valve springs, retainers, etc
* new Tomei Poncams
* Toda cam gears
* Toda timing belt
* MRP ITB Kit w/ new injectors, fuel pressure regulator, vacuum block, etc (https://www.mrpltd.co.nz/product/mrp-4a ... le-bodies/)
* Fujitsubo super EX headers
* Fujitsubo legalis-R exhaust
* standalone ECU and new wiring harness


What springs? Why retainers if you are running such mild cams?


yabaiani wrote:random note...does anyone know of a good set of pistons and rods (not from MRP)? My machine shop said they would look, and I look at CP and only found pistons, not rods. Went to Brian Crower and found Rods. Don’t know if anyone makes both.

Arias just makes pistons...



Molnar Rods... they run about $450 per set... They have 2 different rods depending on which crank you have....

As to pistons, plenty of places make them... not many that you can trust - if you are going to spend $$ on forged pistons - get the right ones! But for your build level(cam choice) you don't need fancy pistons......