Boost Controlling Stock Turbo 7M-GTE

aaknight50

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Ok, so I am relitively new to car modding and tuning, so bare with me. I figured if anyone could answer my question right it'd be you guys. So I have a basically stock 7m-gte in my mk3, besides a complete rebuild including new rods, pistons, rod bearings, crank bearings, port and polished head, bored block (prolly an quarter of a millimeter), ARP headstuds and metal head gasket, as well as all new gaskets all around, relitivley new turbo (maybe 500-1,000 miles), stock injectors, stock fuel pump, new oem oil pump, stock intercooler, etc. Not much done besides brand new parts replacing the old rotted ones. I'm looking at a boost controller https://www.amazon.com/Hallman-PRO-RX-BK-Boost-Controller-Black/dp/B00IFWMQLG, not sure how much boost I should push. Still in the process of putting her back together, so it will be a couple weeks before it hits a dyno. Any help is appreciated, sorry if this is a stupid question, I just figured ya'll would know better than other forums.
 

3p141592654

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With the stock setup you have you will hit boost cut around 9-11 psi. Rather than spend $110 on that mechanical controller, I would suggest you spend you rmoney on opening up the exhaust. A 3" downpipe and catback will make a big difference. I was personally very suprised at the performance boost from my HKS LET-T16 and 3" downpipe. You can get up to 9-11 psi by just adding washers under the existing boost controller on the stock turbo. If you want a variable boost controller buy something electronic like an Blitz SBC Type S Plus Boost Controller for $300. A much better controller than a simple pressure valve. To go beyond 9-11 psi you are going to need to modify the fuel system, AFM, and ECU at the bare minimum. There is a lot of info on such mods posted on this site.
 

Clip

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The above is accurate.

I just finished building my GTE and swapping from my GE, complete with the DM/CXRacing downpipe (opened up a little more), test pipe while I wait for my high flow cat, and 3" catback. The intake consists of a standard K&N cone filter and 2.5" IC piping with a Treadstone IC.

On the engine stand I shimmed the wastegate, then thought it would be better to break it in first before I tried anything else. About 400 miles into the break-in and I gave it plenty of gas only to find fuel cut at about 10.5 psi, no shims needed.

So, my expensive AEM Tru Boost controller that was waiting for installation is sitting on the shelf, unusable for now...until the next box from DM shows up. A lot more $ needed to get by fuel cut now with injectors, fuel pump, regulator, AFM housing and a way to tune.
 

SupraTrbo89

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One thing to add, I would recommend either getting a turbo elbow or a DP with the elbow integrated into it. I think it helps the turbo spool a little quicker. Might as well do both at the same time.

@Clip -- I am surprised you are hitting 10.5 psi with just the DP, test pipe and intercooler. I have the LIPP elbow, random tech DP, test pipe and Blitz NurSpec exhaust and I hit 8psi on a cool night. I assume its b/c you also upgraded your intercooler. I have an HKS intercooler and piping waiting to be installed.
 

Clip

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One thing to add, I would recommend either getting a turbo elbow or a DP with the elbow integrated into it. I think it helps the turbo spool a little quicker. Might as well do both at the same time.

@Clip -- I am surprised you are hitting 10.5 psi with just the DP, test pipe and intercooler. I have the LIPP elbow, random tech DP, test pipe and Blitz NurSpec exhaust and I hit 8psi on a cool night. I assume its b/c you also upgraded your intercooler. I have an HKS intercooler and piping waiting to be installed.
This was at about 75deg, low humidity, Autometer 2601 gauge so I’m fairly sure it’s accurate (and fuel cut confirms). I envy your Nur Spec.

I’ve got the LIPP elbow on the shelf, as I went with the DM downpipe. I spent a little time gasket-matching and smoothing the transitions since it’s made of sheet steel, and running the rest out through an old RS*R Invidia. I picked the Treadstone TRV125 since I read it had a lot better cooling capability compared to CXRacing. The only other thing that might contribute is I’ve removed my locating roll pin from the compressor housing to clock it a few degrees which rotates the WG, but has to be less effect on spring pressure than the 5mm worth of washer.
 
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JustAnotherVictim

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I went with a divorced down pipe on mine, should help with spool up. Never tested it scientifically but I'm happy with it.
Something like this.
1600993907895.png
 

JDMMA70

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One thing to add, I would recommend either getting a turbo elbow or a DP with the elbow integrated into it. I think it helps the turbo spool a little quicker. Might as well do both at the same time.

@Clip -- I am surprised you are hitting 10.5 psi with just the DP, test pipe and intercooler. I have the LIPP elbow, random tech DP, test pipe and Blitz NurSpec exhaust and I hit 8psi on a cool night. I assume its b/c you also upgraded your intercooler. I have an HKS intercooler and piping waiting to be installed.
CXRacing and other China made IC cores tend to have low fin density inside and outside, as a result there is a very low pressure drop end to end so you end up with more boost, however this comes at the expense of cooling. This isn't the same on your HKS core. I have a JDM market HKS IC, and I experimented with a China Spearco copy. At night with a 85'F ambient cruising at 70mph, my HKS core was able to keep the IAT's close to ambient 89'F, and in boost would only rise to 105'F before leveling and slowly dropping slightly with the added airflow. With the Chinese core the best it could manage under the same conditions was 98'F cruising, and in boost it would climb rapidly to 138'F. It climbed so high and so fast that I didnt stay in it due the high IATs. I think this is why the only way you could theoretically get away with a Chinese core is by running a larger thicker core than what would otherwise be normally required.
 
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Clip

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I read something similar on forums when I was researching the stock intercooler about to buy the DM intercooler kit, glad I didn't.

Here's an example, possibly biased but consistent with other forums noting almost 60F rise in IATs. That's crazy.

Air temp after the intercooler at the start of the pull, 62.60 degrees.
Air temp after the intercooler at the end of the pull, 69.80 degrees.
Increase in air temp 7.2 degrees.
Peak boost was 40.3 psi.

We then bolted on the Ebay special that is an AMS attempted copy. Absolutely NO changes were made to anything other than bolting on the I/C.

Car made 633 whp and 505 ft lbs of torque. So not a bad loss at this HP level.

Here is the BAD part.

Air temp after the intercooler at the start of the pull, 62.60 degrees.
Air temp after the intercooler at the end of the pull, 122 degrees!! That is an increase in air temp of 59.4 degrees in a single gear pull!
Peak boost went up which I find strange as it hit 42.1.

The knock count went up considerably with these higher air temps. To run the car safely I would need to pull atleast a few degrees of timing.
 
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JDMMA70

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I read something similar on forums when I was researching the stock intercooler about to buy the DM intercooler kit, glad I didn't.

Here's an example, possibly biased but consistent with other forums noting almost 60F rise in IATs. That's crazy.
Yeah their experience echos my own, although that AMS core sounds REALLY good. I have my data logs somewhere...found em!

China core before pull
CX 1.PNG

China core after pill
CX 2.PNG

HKS core before pull
HKS 1.PNG

HKS core after pull
HKS 2.PNG
 
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JustAnotherVictim

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I had a custom made ddp with atmospheric dump that sounded pretty good, sort of a v-8 sound. It was just so loud that I got annoyed with it after awhile.
Nice and quiet for me now unless it's full on.
 

Zazzn

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Like your mega squirt logs... I should have installed a MAT sensor and tested my stock vs spearco. I'm sure it's not as big as people think.