chiraoka

I had the opportunity to upgrade the stock turbo of a JDM EVO 7 GSR, which is or should be identical to the turbo found on the USDM EVO 8. Basically the owner of an EVO 6 group N rally car switched parts, he gave me his bigger exhaust housing, which is a 10.5T and replaced it with the smaller 9.8T housing found on the EVO 7 turbo. After all he was after more low end torque, and I was looking for better top end .....

The swap was an easy job.

The car has only got a 3inch HKS Hyper exhaust, a HKS air filter, and a TurboXS HPBC ..... other than that the car is stock. Well in order to sort out the fueling a SAFC 2 was installed. Before we the stock turbos on the EVO 7's we used to take away some fuel, not the same amount as I have reading on the board but upto 6% less at top end, using 21psi peak boost which tappered to 17psi at top end. But with the change of exhaust housing, we had to add fuel all the way from 4000 rpm upto 7200rpm. Boost right now is set to 19psi which drops to 17psi at top end, we couldn't use more since we got boost cut, and since we had to dial upto 10% more on the SAFC2 obviously we found the cut at much lower boost. Right now the AFR measured with a NTK UEGO type sensor are around 11.5:1 but definetly a better fuel pump and at least a fuel regulator is needed to lower the settings on the SAFC and also raise the boost. Needless to say the car is much much better than any other EVO 7's we have around, it just feels a lot better at top end, and low end is still very very good. It pulls very similar to a EVO 7, with the supporting mods and stock turbo, on 1st and 2nd gear, but once you change to 3rd gear it's bye bye .

Don't know if u guys can get the hot side of the EVO 6 turbo, BTW the stock turbo of a JDM EVO 6 GSR is a:
TD05HR-16G6-10.5T (GSR)
Nozzle Area (cm2) = 10.5

should be an interesting mod, if someone could supply the 10.5T TD05 hotside, I will post pictures on monday so that you guys could check out the differences .....

Regards,

Carlos H.
Lima - Peru

MP5

iTrader: (4)

Interesting indeed. Have you changed cams in your quest for more top end? They help a bunch. Also is the 7s turbo twin scroll? How bout the hotside you put in twin or single?

chiraoka

cams r the stock ones found on the JDM EVO 7's, which are quite common here in Lima ..... that will be next on the agenda, but after installing next week a Walbro fuel pump and a adjustable 1:1 fuel pressure regulator.

The JDM EVO 7 is very very similar to the USDM EVO 8, in fact it uses the same turbo (although I don't know if the cams are similar), I know this cause the rally guys who use EVO 7's are buying now turbos in the US instead of importing them from Europe or Japan. So they are also twin scroll. The EVO 6 hotside is also twin scroll and like I said it is basically a bolt on job, although a little harder because of the work involved ..... but definetly worth it .

Carlos H.

chiraoka

BTW "usually" the JDM ECUs are programed slightly leaner than the euro spec / USDM ECUs ..... so that is why on the stock EVO 7's we take out less fuel than u guys with the SAFC2.

Carlos H.

Zeus

iTrader: (66)

This is getting good...

raywong

my car is running a little too rich, and I just want to lower the A/F a little. I need to ask some questions to make sure I really need that SAFC2.
1. Does less restrictive exhaust result in leaner A/F ratio?
2. Is it true that higher boost setting will max out my fuel pump at hi rpm, therefore lean out the A/F?
3. Does SAFC2 make your power curve non-smooth?

1QWKEVO

iTrader: (3)

all turbos from the Evo IV model are twin scroll

MP5

iTrader: (4)

Carlos what kinda spool did you loose?(it looks by your post that you ARE getting that 19psi by 4K but Id like you to confirm)9.8 is a pretty decent housing especially with the icreased VE of bigger cams. What Im getting at is the cams are likely to give another increase in top end (that I understand your after) but with that 10.5 backend will prolly come a increase in lag to the right of the band. It might not be to bad considering we have the same cold side here but at what point do you feel the diminishing returns come into play as well as the turbo spinning too fast? I say this cause the way to increase the cfm is to spin it faster if you plan on keeping the frontside asembly. Seems this is a good mod but I also feel that some head work would give similar gains- Hell do both if you want to maximize the current 16G

chiraoka

I will try to make this clear (sorry for my english, my native language is spanish). The stock JDM EVO 7 turbo which is identical to the turbo found on the USDM EVO 8 spools very very fast, and that is why I guess that the rally boys love it, since it makes over 1 bar of boost before 3000rpm on 4th and 5th gear.
The turbo I am currently playing with, is a stock JDM EVO 7 turbo (non Titanium) with the 10.5T hot side, so in a few words it is an EVO 6 GSR turbo, which is the biggest one fitted to an EVO. I am getting peak boost or 19psi in 3rd and 4th gear at 3500-3600 rpm. I have not felt that a noticeable increase in lag, after all this is basically the same turbo that came in the EVO 6 GSR .
Although we do not have dynos here, I was impressed by the xtra fuel needed to support 19psi on this turbo, when compared to the 19psi on the stock unit.
BTW the group N EVO 6 rally car (group N rally cars use a 32mm air restrictor) used upto 1.8bar of boost at midrange which then quickly falls, and on the other side of the pond, this turbo is used with very high boost with no problems.

Carlos H.

chiraoka

Today I will be installing a bigger Walbro fuel pump and see if I can reduce the settings on the SAFC (which are around +10% at top end) ..... hopefully we will be able to increase at least 1-2psi of boost . Will report later.

Carlos H.

ItsStockOfficer

Does anyone else ever feel inferior because it seems like everyone but us can speak two languages? I mean, Of course everyone knows we Americans are The BEST.....but I wish was Like Carlos and spoke....Limaese...Peruian? Whatever he speaks, at least its not Spanish.

Kidding but serious, I wish I was bi-lingual.

ItsStockOfficer

You need larger injectors...If you go positive on SAFC settings the ECU will be seeing more airflow then its actually getting which will lead to two problems

A. You will hit fuel cut much easier.

B. Mitsu ECU's pull out ignition timing based on airflow, so you are hurting your own power significantly.

chiraoka

Well back from the workshop ..... like I thought we were max'ing the stock fuel pump. The Walbro fuel pump was installed, and now at 20psi of boost (we are not hitting fuel cut) at top end sustained the SAFC settings are down to +4% , engine feels much much better and pulls hard all the way to 7500 were the rpm limit is.
Next on the list is a adjustable FPR to lower even more the SAFC settings and probably raise the boost a little bit more ..... so far we have no det at all, we have 97 RON fuel over here.

Only big problem we have found is that the JDM speedometer has a max speed of 180 km/h .....

Carlos H.

the evo wins

iTrader: (3)

yeah we even have the best president in the world!

chiraoka

the only bolt on FPR that I have read of this one:



anyone know of any other good 1:1 FPR ?????

Carlos H.