highest boost ran on a jdm 7m safely?

F

ferny

Guest
lets say if i get a good headgasket. and get a nice fmic
downpipe.full 3 inch exhaust piping and a nice muff
whats the most i can run on boost safely on 91 octane?
and around what numbers would i be looking at in hp and in torque and what rpms.
if anyone could help i would really appreciate it. thank you. :icon_bigg
 

lagged

1991 1JZ
Mar 30, 2005
2,616
0
0
38
new rochelle
your question sucks. theres too many different variables.

stock turbo? you should only run 15 pounds on a stock turbo.

beyond that with an upgraded turbo, it all depends on tuning and detonation control.
 

kamil

87T Targa
Apr 4, 2005
144
0
0
Tucson, AZ
No Problem!

ma71supraturbo said:
Modification Order, MK3 Supra Turbo

There are many possible modification orders, but this staged list is the system I recommend for increasing your 7m-gte's power while maintaining good reliability. Please do not begin modifying unless your car is well maintained and running with no problems (i.e. proper head gasket, no overheating issues, good vacuum, good oil pressure, no misses, etc). Additionally please continue to keep up on your car's maintainence. A vacume leak at the accoridan hose, for example, is not a particularly dangerous condition for a stock mk3. But if your car is tuned for optimum power, you have taken away the extra safety of the over-rich factory tune and you could end up doing severe damage by running lean.

The following horsepower figures are estimated at the crank (bhp) and are based on a perfectly running mk3. For reference, a stock MK3 makes 230bhp (232bhp 89+) @ 6.8psi. I chose to list crank HP estimates for a few reasons. Automatic and manual cars make the same power at the engine, but manuals put more of that power to the ground (12-15% M/T drivetrain loss verses ~18-20% A/T). Additionally, modifications like light-weight flywheels and driveshafts will increase the rear wheel horsepower without actually increasing the power at the crank. And finally, because manufacturers list crank horsepower figures so this allows more of a direct comparison with newer cars. That said, it is important to realize that your car may make more or less power depending on a number of factors, so please take these and all horsepower figures with a grain of salt.



Stage 1:
Intake, 235bhp @ 7psi

Intake_Systems_SUS_POWER_Air_Filter_Kit_(Stainless_Mesh_Filter).jpg
The first thing to do in increasing any engine's performance is to make sure it can flow plenty of air. The simplest way to help an engine breathe better is by installing an aftermarket intake. There are many different brands out there, but Apexi performed the best in this test. For hints on installing a full intake kit, please see this tech tip. While you are at it, I also recommend the SOGI cold-air intake mod.


Stage 2:
Cat-back, 250bhp @ ~8psi

Exhaust_Systems_Super_Medallion_Hyper_Spec.jpg
Continuing with the theme of better breathing, the next step is to install a cat-back exhaust. There are even more brands and styles of exhausts than intakes, so take your time and find one which best fits your needs for flow, looks, and sound. If you live in an area where corrosion is a problem, you probably will not want to settle for anything less than a full stainless system.


Stage 3:
Downpipe/elbow/primary cat or test pipe, 280bhp @ ~9psi

Downpipes_Divorced.jpg
If you still want more power, then its time to replace the restrictive stock downpipe, turbo elbow, and secondary catalytic converter. This picture shows one of the simpler downpipes, although there are some downpipes that integrate a turbo elbow and test pipe in one unit. For the environmentally concerned, Random Technologies makes a high-flow cat that will replace the secondary cat, but it obviously will not flow as well as a "test pipe." One word of caution -- downpipes are not legal in all states as they replace the primary catalytic converter.


Stage 3.5:
Gauges


apex60mm_boost.jpg
While gauges do not increase power, it is important especially if you want to continue modifying. At this point, you're probably already boosting 9 psi, which exceeds the stock boost gauge. Installing a new one, along with an Exhaust Gas Temperature (EGT) gauge is also a good idea. An Air/Fuel ratio gauge is also good, but readings based on your factory O2 sensor are next to worthless so a wideband 02 sensor would be necessary. Other good gauges to consider are water temperature, oil pressure, and oil temperature. If you can afford it, look for gauges with a peak hold feature. These can be very helpful, as you cannot always pay close attention to your gauges when you are driving hard.


Stage 4:
Boost controller, 300bhp @ just under fuel cut

Boost_Controllers_Profec_B_Spec_II.jpg
Now that your engine can breathe freely and you can monitor what it's doing, it is time to turn up the boost with a boost controller. There are inexpensive manual boost controllers out there, but I have found it to be a pain to get out and adjust them every time the weather changes. The solution is an electronic boost controller which can not only be adjusted from inside the car, but some can also learn to better control your wastegate allowing the turbo to spool much faster.


Stage 5:
Intercooler and hardpipes, 320bhp @ just under fuel cut

hks_fmic.jpg
If you still want more power, you will need to replace your stock intercooler and the restrictive stock intercooler piping. Compressing air creates heat, which can lead to detonation. Since you want to turn up the boost even more, you'll need an intercooler that can not only flow better but also do a better job of keeping the air cool. It also is a good idea to replace your factory bypass valve to prevent compressor surge.


Stage 5.5
fuel pump

dpump.jpg
When you try to boost too high, your ECU will cut fuel momentarily to prevent engine damage. Now that you want to exceed that limit, it is time to upgrade your fuel system. While it is possible to boost a little over fuel cut on the stock fuel system, it is not recommended -- especially if you have your sights set significantly higher. The first step to upgrading your fuel system is to then replace the fuel pump with one that can move more fuel. Walbro and the stock MKIV tt pump are common choices.


Stage 6:
Lexus AFM/550 injectors, 340bhp @ 15psi

injectors1.gif
One of the most common ways around fuel cut is to use an Air Flow Meter off a Lexus V8. The basic gist is this air flow meter allows some unmetered air through tricking the stock ECU into thinking it is getting less air than it really is. Because the ECU thinks it is getting less air, the boost at which you hit fuel cut goes up. To offset this extra air, 550 injectors replace the stock 440 units. Details on this upgrade can be found here. Recently, PHR has announced they will make a "map ecu" that will allow consumers to use a much less restrictive MAP sensor instead of an AFM. Details on this product can be found here.


Stage 7:
Fuel tuning device and dyno tuning, 375bhp @ 16psi

apexsafc.jpg
At this point, the car could benefit from some fine-tuning. Chances are you will be running rich, so an air/fuel controller can lean out the mixture and help further raise fuel cut. There are many options out there, so do a little research and decide on the best unit for your goals. If you must have the best, a standalone is the way to go but it is much more expensive, and is more difficult to tune (chances are you will have to have a professional tune it).



Stage 8:
Upgraded turbo

Turbo_Kits_SP60_for_MK3_Supra.jpg
You have now reached the useable limits of the stock turbo. It is possible to further increase the boost, but the turbo will be blowing such hot air that you will experience diminishing returns. Which turbo you go with will depend entirely on how far you want to take your Supra. If 450bhp or less is ok you can go with an upgraded CT26. 550bhp or less and you can go with a bolt-on hybrid turbo. If that is not enough, then you will be looking at a bigger turbo kit that replaces the exhaust manifold.




Here is the "original" stage chart that HKS put out years ago. It's main limitation is that it does not include a downpipe, turbo elbow, or test pipe so the upper horsepower figures are lower than people commonly see today:


1. Cat-back exhaust 251 bhp @ 8 psi

2. Super Power Flow Intake 259 bhp @ 8.5 psi

3. HKS EVC IV (boost controller) 285 bhp @11 psi

4. Intercooler kit 298 bhp @ 11.5 psi

5. PFC-FCON w/FCD 330 bhp @13.5 psi

6. Vein Pressure Converter 345 bhp @ 13.5 psi

7. Sport Turbo Upgrade/550cc injectors 438 bhp @ 15 psi

8. Cam Shafts, Cam Gears 453 bhp @ 15psi
 

figgie

Supramania Contributor
Mar 30, 2005
5,224
16
38
49
Twin Cities, Minnesot-ah
suprabad said:
One small correction...manuals put more power to the rear wheels...not necessarily to the ground! You guys are always bashing automatics.

dude that is a contradiction in and onto itself

if the rear wheels get more power. how the fuck is it NOT going to get more power to the ground????
 

SuprAng

Garage Queen VV
Apr 4, 2005
112
0
16
Toronto, ON
suprabad said:
One small correction...manuals put more power to the rear wheels...not necessarily to the ground! You guys are always bashing automatics.


LOL, ok ill play your game...

soooo BIG turbos put more power to the rear wheels... not necessarily to the ground...

therefore we shouldnt even run turbos :icon_conf