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Old 01-10-2018, 06:52 PM
Supraman Supraman is offline
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Join Date: Nov 2017
Location: Baltimore
Posts: 11
Turbo, piggy-back, and EG33 boost questions

Hello guys,

New guy to the SVX here. Not new to boosted cars though. I have a few questions after researching your forays into boosting the EG33.

1. Why don't you use piggy-backs? MAPECU2-4, SAFC/VPC combos?
These two we use on 2jz, 4g63, and Honda motors all the time.
Allows u to remove the MAF and run MAP system. NA or boosted
they work well and are easy to use with a good wideband.

2. Since knock is gonna be a problem if you raise boost to 8-10psi
why not use meth or water injection? Another mod we use very
well. Since winshield washer fluid is mostly meth...u can buy it
anywhere in a pinch.

3. Why not use one single mount rear turbo back where the cat is?
Easy install and you can do this yourself in a weekend with little
outlay of money. I know some will say lag is a problem...But us
Supra guys call lag a "head start" for the other guy !!! Plus you
get pretty decent gas mileage around town,and hardly any
welding involved. can buy most of your hard piping
from !!!

I have some STS turbos from my room mates 2010 Camaro I was
gonna try to mount with a SMIC from a Supra to try some of these
ideas on my $200 95 LSi I just got. Running at 5-7psi. Using a
SAFC/VPC and 440-550 injectors. With a Supra fuelpump. Stuff
I have laying around really.

The 95 has a rebuilt trans and only 150k just needs valve cover
gaskets and PCV valve.

Having boosted several NA cars in my life I don't see what the big problem
here is with getting a reliable 100whp out of the EG33.

Boost is boost. Nothing special to it if u follow the rules...

1. Don't get greedy
2. Keep those AFR's around 11.9-12.8
3. proper cooling. tranny,boost and oil.

Unless I'm missing something here? I'm not looking for a street terror. I can
hop in one of my Supras for that. Just feel this car needs another
80-100whp and those glorious turbo sounds to go with its awesome looks !!!

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Old 01-11-2018, 01:11 PM
bheinen74 bheinen74 is offline
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Join Date: Nov 2008
Location: Iowa
Posts: 651
Registered SVX
Re: Turbo, piggy-back, and EG33 boost questions

just going to a 4.11 or 4.44 gearing will give you the same equiv in seat of pants as the 80-100hp.

the car is heavy, so that is the hurt factor. I have had a 92 stock svx and a 97 stock svx.
I have had 92 Legacy Turbo 5mt slight mods with exhaust, 94 Legacy Turbo 5mt running a maual boost controller, a 94 Legacy turbo wagon 4eat, a 93legacy turbo 4eat, another 94SS 5mt stock, and now own a 91 SS stock.

Those old Tlegs have more scoot than the SVX, at lower HP. It is in the chassis and gearing , my old T wagon was probably the most fun of all, it looked like a sleeper, but it ate Camaros and Mustangs for breakfast and asked for even more abuse. I sold that car 2 times even after buying it back once after the owner had it 4 years+. That thing was a BEAST in super mode.

Gear change, and report back.
1985 Brat GL 138k
91 CRX Si 40k
91 CRX Si 155k
97 SVX Lsi 70k
2003 s2000
91 RT4WD 166K
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Old 01-16-2018, 03:00 PM
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Nevin Nevin is offline
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Join Date: Jul 2007
Location: Kalona, IA
Posts: 1,178
Re: Turbo, piggy-back, and EG33 boost questions

Since the number of SVX out there is so low, that's the main reason you don't see many that are boosted, I would say. Not many people want to spend the time or effort on a car where they would literally have to start from scratch.

I see no problem in boosting the motor like you say though. I do plenty of fab work myself, and don't see any major problems with putting 6-10 psi of boost on one of these motors. As you say; watch your AFR's, knock, and keep your IAT's low, and there's no reason you couldn't get another 75 horse out of these without touching the bottom end in even the most basic setup. It's lack of R&D on these that scares people, most kids pick up these cars, and go ZOMG AWD 230 hp amazing!! And don't realize that if you want something for these cars, you literally have to make it yourself.

Weight in and of itself is not an issue, but obviously it is a contributing factor when doing a timing map, which would obviously affect horsepower. These cars are no heavier than a newer LGT, and obviously they are still capable of bigger HP numbers.

The EG33 itself if it had a proper standalone and an experienced tuner behind the helm, would not be the weak link. I see no reason that a motor in good shape could not put out 500 hp on the stock bottom end. Tuning and engine management techniques and computers are SO far beyond what they were even 5 years ago, the amount of precision just keeps going up and up, allowing for higher and safer Hp numbers.

My long term project is to reverse the exhaust manifolds, and do a low mount twin turbo setup. With some planning and time, you could make whatever you want! Put that with the stock 3.54 gears with a built tranny and you would have a highway monster.
Jesus is the remedy
Black '94 Probe GT too much work to list...
Silver '02 WRX wagon 5-sp the new daily
Ebony Pearl '95 Subaru SVX LSi

Home of the Bontrager Works 22mm rear sway bar!!
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Old 04-28-2018, 06:33 PM
SoCoNoHa's Avatar
SoCoNoHa SoCoNoHa is offline
H6 Fanatic
Join Date: Nov 2016
Location: Southern NH
Posts: 76
Registered SVX
Re: Turbo, piggy-back, and EG33 boost questions

+1 for the gear change. I have a 99 Legacy GT 5 speed in my SVX and I would describe the acceleration as 'frantic'. It's certainly not the fastest thing on the road but it pulls like a train from 2k almost to redline.

But also boost it and keep it well documented please! I'm not the only one that wound love to see it. Port the hell outta the exhaust, primarily the dogleg. Should give good results from what I've read.

Getting the old itch to boost my SVX again...
1992 SVX LS-L - Classic Cruiser
^Pearl White/Black, 5MT
1997 Legacy GT Sedan - Project
^Rio Red, 5MT, TD04, FMIC
1995 Impreza Coupe - Racecar
^Acadia Green, 5MT, EZ30
2002 Impreza Sedan - Daily for now
^Silver, 5MT, Swift Springs
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Old 04-28-2018, 10:13 PM
92 SVX 92 SVX is offline
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Join Date: Feb 2010
Location: Jax Florida
Posts: 1,468
Registered SVX
Re: Turbo, piggy-back, and EG33 boost questions

I am not sure why you would want to run a piggyback system, full stand alone will give you more options at only a small uptick in price (from what I have seen) one main reason so many I know do not like the piggyback is because the ecu is on the dumber side and messing with the values it sees can lead to funky stuff. that and wiring nightmares...
As to what the engine can handle...... I know of at least one stock engine running a monster turbo (in Australia) Last I heard he was running 12 psi of boost and somewhere close to 500 HP at the wheels.

Last edited by 92 SVX; 04-29-2018 at 11:56 AM.
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Old 10-01-2019, 11:21 AM
SoCoNoHa's Avatar
SoCoNoHa SoCoNoHa is offline
H6 Fanatic
Join Date: Nov 2016
Location: Southern NH
Posts: 76
Registered SVX
Re: Turbo, piggy-back, and EG33 boost questions

I'd like to weigh in on this, again. I have a piggy back I love, the AEM FIC6. Also a gear change is NOTHING compared to even 5 psi of properly managed boost.

Prior to using a piggyback on my Impreza, I had zero experience tuning. Still haven't used a stand alone, and they certainly give one more control and function, but at the cost of greatly increased price and complexity. I've seen name brand systems quoted at over ten times what my piggyback cost me.

The thing wired in pretty simply, and operating it is a breeze. Since it tweaks signals to and from the ECU, I get no trouble codes from sensors that aren't supposed to see positive manifold pressure. Fuel/timing/MAF signal/O2 signal/more can be altered based on throttle position/load/rpms/whatever. I can adjust maps on the fly, and witness the results within about 2 seconds.

In summation, it's a pretty good setup for up to 25psi (should be plenty for an EG) and it only ran me ~$350 on eBay. Good for up to 6 cylinders, too!

Anyone else got a piggy back or standalone?
1992 SVX LS-L - Classic Cruiser
^Pearl White/Black, 5MT
1997 Legacy GT Sedan - Project
^Rio Red, 5MT, TD04, FMIC
1995 Impreza Coupe - Racecar
^Acadia Green, 5MT, EZ30
2002 Impreza Sedan - Daily for now
^Silver, 5MT, Swift Springs

Last edited by SoCoNoHa; 10-01-2019 at 11:25 AM.
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