Evo boost question

[CassiesMan]

Hey all, Im gonna be getting a new car in about a year or so, and I like to start shopping and doing my homework early. Allthough I'm looking mostly into used cars, one of the few new cars I'm looking at is the Evo VIII or MR if I can get a deal on one. I just have one question. With the 4G63 in the Evos, what is the safe level of boost with basic bolt ons (DP, Exhaust, Intake, MBC)? I know in a few cars, you can up the bost with those parts near 20psi, and was wondering how much one could up the boost to with those parts in the Evo.

[noevosplease]

stock is 17.4psi...thats near 20psi.

[CassiesMan]

Originally Posted by noevosplease

stock is 17.4psi...thats near 20psi.

I was just going of what I know with Supras, being that, with I/DP/E?MBC, you can boost 17-18psi. I was wondeirng that, with I/DP/E/MBC, what can I boost with an Evo?

[gsxeclipse97]

Im sorry but the stock boost for an evo is not 17.4 it is 19.4 then it drops down to 17 something becuase the computer tells it to. with down pipe and exhause you should be able to safely run 24 25psi but you will be falling out of the range for the turbo i wouldn't go any higher than that on the stock fuel system.

[Stanimal]

You'll start to run lean if you're running over 21 psi above 6000 rpm. So a fuel pump is in order. I would also add head studs if you plan to dial it past 22-23 psi. These are pretty inexpensive add-ons. At that point you should be putting out 300 - 330 WHP which is pretty good considering stock is around 240-250 WHP. You could get another 20+ with chip and dyno tune and 20 more with cams and timing gear.

After that you'll need a bigger turbo, the stock turbo would be so far off of the island it'll just be heating up the intake charge.

[gsxeclipse97]

Correct me if im wrong but i believe the evo is basicly set up to be able to do 400 hp with minor things bolt ons and with an safc boost controller. the evo does come with a front mount so he could turn it up to about 25 not like the gsx with a 16g and a shity side mount

[Stanimal]

Originally Posted by gsxeclipse97

Correct me if im wrong but i believe the evo is basicly set up to be able to do 400 hp with minor things bolt ons and with an safc boost controller. the evo does come with a front mount so he could turn it up to about 25 not like the gsx with a 16g and a shity side mount

gsxeclipse97, I think you're right about the power output if you're talking about crank HP.

The EVO's 4G63's bottom end is rock solid, but 400 WHP on an accurate dyno on 93 octane pump gas with the stock 16G big turbo would be hard to do. And 25 psig on the stock turbo at 6000 rpm would be so far off of the compressor's efficiency island we'd just be heating up the intake and not making much more power.

[gsxeclipse97]

what is the cfm flow for the evo 8 turbo. I know that the evo 3 is 550 cfm's and you can run 25 psi on that turbo with supporting mods and make a good amount of power. I'm not sure how different the turbos are other than the twin scroll but should be close in power range..

[Stanimal]

Originally Posted by gsxeclipse97

what is the cfm flow for the evo 8 turbo. I know that the evo 3 is 550 cfm's and you can run 25 psi on that turbo with supporting mods and make a good amount of power. I'm not sure how different the turbos are other than the twin scroll but should be close in power range..

The Evo 3 has the TD05H–16G6-7 (7cm^2 nozzle area), inconel turbine wheel and 68mm aluminum compressor. Peak efficiency for this compressor is a high 77%.

This compressor is way pass choke @ 550 CFM. According to the compressor map, at a 2.7 PR (25 psig @ at sea level) this compressor max out at 490 CFM running at rated max speed of 151,274 RPM @ 70% eff. This compressor has max flow between PR 2.0 and 2.4 (14.7 - 20.5 psig), @ 520 CPM but down to a low 60% eff.

The EVO 8 has the TD05HR-16G6-9.8T (9.8cm^2 nozzle area), inconel turbine wheel and 68mm aluminum compressor. Peak efficiency for this compressor is a so so 71%. With this lower efficiency, the compressor will dump a lot of heat in the intake charge and really need the intercooler.

This compressor is near choke @ 550 CFM. According to the compressor map, at 2.7 PR, this compressor max out at 560 CFM running at rated max speed of 150,000 RPM @ a lowly 60% eff. It's making lots of heat at this point. This compressor has max flow between PR 2.4 and 2.7 (20.5 - 25 psig), @ 560 CPM. The eff is very poor at this point (60%).

Also please keep in mind, when you are running the compressor near the choke point, you'll be drawing lot more power from the turbine and producing huge back pressure, which kills HP.

I would never say you couldn't make 400 WHP with the stock turbo, if I recall correctly, a couple of tuners have already done so. However, these guys are great and I think they mod just about everything except the turbo and the bottom end, used race gas and most added alcohol injection.

Personally, if I were to max out the stock turbo on the Evo 8, I would probably stay below 23 psig (2.6 PR) and 490 CFM. At that point, the compressor is still at 68% (only 3% off peak) and 130,000 RPM. With reasonable mods, this should be good for ~350 WHP with the stock intercooler. This is a huge 40+% bump from stock without putting huge stresses on the engine. As a bonus, I might even be able to run 93 oct pump gas.

My idea of reasonable mods:
3" well designed turbo back exhaust
cams
timing gear
computer and dyno tune
MBC
fuel pump
head studs
K&N panel filter

optional:
injectors

And if you play at this power level, you'll need a new clutch shortly.

[gsxeclipse97]

Well that clears everything up, But many people port the outlet hole on the evo 3 so in theroy the evo 3 is a better turbo.

[EVOlutionary]

Wow. Do any of you guys even own an EVO? For accurate and correct information on what power you will get from each mod, as well as how the boost works and how much you can run safely check here:

http://forums.evolutionm.net/showthr...ur+dyno+thread

and here:

http://forums.evolutionm.net/showthr...ur+dyno+thread

Be patient, take your time and read the whole thing. Last I checked it was around 36 pages. David Buschur goes step by step adding one part after another and dynoing it after every part. You will learn about what boost to run. You will learn about boost taper and how it gets worse on the stock turbo as you increase the efficiency of the engine system.

Trust me, it is worth the read. My advice is to listen to what the professionals have to say and then decide what is right for your car. Do not base it on what some guy (me included) on a message board tells you to do.

Good luck with your future car purchase. The EVO is certainly the way to go!!

EVOlutionary

[motoworkz]

Originally Posted by Stanimal

The Evo 3 has the TD05H–16G6-7 (7cm^2 nozzle area), inconel turbine wheel and 68mm aluminum compressor. Peak efficiency for this compressor is a high 77%.

This compressor is way pass choke @ 550 CFM. According to the compressor map, at a 2.7 PR (25 psig @ at sea level) this compressor max out at 490 CFM running at rated max speed of 151,274 RPM @ 70% eff. This compressor has max flow between PR 2.0 and 2.4 (14.7 - 20.5 psig), @ 520 CPM but down to a low 60% eff.

The EVO 8 has the TD05HR-16G6-9.8T (9.8cm^2 nozzle area), inconel turbine wheel and 68mm aluminum compressor. Peak efficiency for this compressor is a so so 71%. With this lower efficiency, the compressor will dump a lot of heat in the intake charge and really need the intercooler.

This compressor is near choke @ 550 CFM. According to the compressor map, at 2.7 PR, this compressor max out at 560 CFM running at rated max speed of 150,000 RPM @ a lowly 60% eff. It's making lots of heat at this point. This compressor has max flow between PR 2.4 and 2.7 (20.5 - 25 psig), @ 560 CPM. The eff is very poor at this point (60%).

Also please keep in mind, when you are running the compressor near the choke point, you'll be drawing lot more power from the turbine and producing huge back pressure, which kills HP.

I would never say you couldn't make 400 WHP with the stock turbo, if I recall correctly, a couple of tuners have already done so. However, these guys are great and I think they mod just about everything except the turbo and the bottom end, used race gas and most added alcohol injection.

Personally, if I were to max out the stock turbo on the Evo 8, I would probably stay below 23 psig (2.6 PR) and 490 CFM. At that point, the compressor is still at 68% (only 3% off peak) and 130,000 RPM. With reasonable mods, this should be good for ~350 WHP with the stock intercooler. This is a huge 40+% bump from stock without putting huge stresses on the engine. As a bonus, I might even be able to run 93 oct pump gas.

My idea of reasonable mods:
3" well designed turbo back exhaust
cams
timing gear
computer and dyno tune
MBC
fuel pump
head studs
K&N panel filter

optional:
injectors

And if you play at this power level, you'll need a new clutch shortly.

Not trying to diss on you or anything but I don't under stand what PR is. I think you mean BAR. Please clarify.

Here is a table for the readings of pressure:

Pressure or mechanical stress
Pressure atmosphere (standard)atm≡ 101 325 Pa [8]
atmosphere (technical)at≡ 1 kgf/cm²= 98.0665 ×10−3 Pa [8]
bar bar≡ 105 Pabarye (cgs unit) ≡ 1 dyn/cm²= 0.1
Pacentimetre of mercurycmHg≡ 13 595.1 kg/m³ × 1 cm × g≈ 1.333 22 ×10−3 Pa [8]centimetre of water (4 °C)cmH2O≈ 999.972 kg/m³ × 1 cm × g≈ 98.0638 Pa [8]
foot of mercury (conventional)ftHg≡ 13 595.1 kg/m³ × 1 ft × g≈ 40.636 66 ×10−3 Pa [8]
foot of water (39.2 °F)ftH2O≈ 999.972 kg/m³ × 1 ft × g≈ 2.988 98 ×10−3 Pa [8]
inch of mercury (conventional)inHg≡ 13 595.1 kg/m³ × 1 in × g≈ 3.386 389 ×10−3 Pa [8]
inch of water (39.2 °F)inH2O≈ 999.972 kg/m³ × 1 in × g≈ 249.082 Pa [8]kilogram-force per square millimetrekgf/mm²≡ 1 kgf/mm²= 9.806 65 ×10−6 Pa [8]
kip per square inchksi≡ 1 kipf/sq in≈ 6.894757 ×106 Pa [8]
millimetre of mercurymmHg≡ 13 595.1 kg/m³ × 1 mm × g ≈ 1 torr≈ 133.322 4 Pa [8]
millimetre of water (3.98 °C)mmH2O≈ 999.972 kg/m³ × 1 mm × g = 0.999972 kgf/m²= 9.806 38 Pa
pascal (SI unit)Pa≡ N/m² = kg/(m·s²)= 1 Pa [9]pièze (mts unit)pz≡ 1000 kg/m·s²= 1 ×10−3 Pa
pound per square footpsf≡ 1 lbf/ft²≈ 47.880 25 Pa [8]
poundal per square footpdl/sq ft≡ 1 pdl/sq ft≈ 1.488 164 Pa [8]
pound per square inchpsi≡ 1 lbf/in²≈ 6.894 757 ×10+3 Pa [8]
short ton per square foot ≡ 1 sh tn × g / 1 sq ft≈ 95.760 518 ×10+3 Pa
torrtorr≡ 101 325/760 Pa≈ 133.322 4 Pa [8]

[motoworkz]

Originally Posted by gsxeclipse97

Im sorry but the stock boost for an evo is not 17.4 it is 19.4 then it drops down to 17 something becuase the computer tells it to. with down pipe and exhause you should be able to safely run 24 25psi but you will be falling out of the range for the turbo i wouldn't go any higher than that on the stock fuel system.

Same thing on this one. Not trying to diss but just want people to get the right info. Usually car manufacturers like to quote the the boost levels based on the actual boost levels (stable readings). So if it is rated at 17.4 and spikes at 19.4 then they would use 17.4. No one quotes the spike reading unless they are trying to compensate the "boost spike" so they don't blow the motor. Nothing a good wastegate and boost controller can fix.

[Stanimal]

[quote=motoworkz]Not trying to diss on you or anything but I don't under stand what PR is. I think you mean BAR. Please clarify.

PR = Pressure Ratio
1.0 PR = Ambient air pressure ~ 14.7 PSIa at sea level or 0 PSIg
2.0 PR = 2 atmospheres of air pressure ~ 29+ PSIa or ~15 PSIg

PSIa is absolute air pressure (0 = vacuum)
PSIg is gauge air pressure (0 = 14.7 PSIa) or boost

But if you're in Denver @ 5000 ft. The ambient air pressure might be 12.2 PSIa, and at a PR of 2.0, your turbo would be pumping ot 12.2 X 2 = 24.4 PSIa or 24.4 - 12.2 (0 point on boost gauge) = 12.2 PSIg of boost instead of the 14.7 PSIg you would have seen at sea level. (This is only acurate if the turbo was not being regulated by the waste gate or the blow off valve at this load)

[AWDTurboFreak]

You can run about 22-24psi max with those mods. I have 2 friends I race with and both of them have EVO9's built and tuned by Leafracing.com . One is an MR and the other is a regular EVO. Both of them are tuned to run 24psi. They both have basic mods. They've been running 24psi for a while now with no probs at all.