Toyota 2L 3L 5L Turbo Install in Cabover Truck (1 Viewer)

[utleymu]

If you can run the air intake out to a cooler area you'll make gains in spool-up and EGT.

I put a new air-filter housings in one of my vehicles a few years back and ran it for a little bit sucking engine bay air. It really sucked. Boost was slow, EGT was high and I had visible smoke.
When I finished the install and put the intake tube back to the front all that came right.

Yeah, it's definitely not ideal. Unfortunately, it's a really tight space. To route intake tubing to the front where the stock airbox is, I’d have to delete the intercooler. The stock airbox location is also quite low, making it prone to water intrusion, which isn’t great either. Pretty much chose to go with an intercooler over having a cooler air intake location. Not sure if it's the right choice or not.

It might be possible to fabricate a snorkel that exits out the rear of the engine bay and runs between the front and rear doors, similar to the Hiace vans. However, I’m not sure there’s enough space for that, and it would require relocating some other components. Overall, I think this is beyond my current skill level.

For now, I’m going to add some exhaust wrap, a turbo blanket, and a heat shield. I hope these modifications, combined with the intercooler, will help mitigate some of the heat-related issues of having the intake in the engine bay. I haven’t adjusted the fuel screw yet, but my EGTs are really low, and I’m making plenty of boost easily, so I think I have some room to work with.

 

[Dougal]

Yeah, it's definitely not ideal. Unfortunately, it's a really tight space. To route intake tubing to the front where the stock airbox is, I’d have to delete the intercooler. The stock airbox location is also quite low, making it prone to water intrusion, which isn’t great either. Pretty much chose to go with an intercooler over having a cooler air intake location. Not sure if it's the right choice or not.

It might be possible to fabricate a snorkel that exits out the rear of the engine bay and runs between the front and rear doors, similar to the Hiace vans. However, I’m not sure there’s enough space for that, and it would require relocating some other components. Overall, I think this is beyond my current skill level.

For now, I’m going to add some exhaust wrap, a turbo blanket, and a heat shield. I hope these modifications, combined with the intercooler, will help mitigate some of the heat-related issues of having the intake in the engine bay. I haven’t adjusted the fuel screw yet, but my EGTs are really low, and I’m making plenty of boost easily, so I think I have some room to work with.

Any sort of shield that will deflect the hot air off the radiator fan will help the most for the least work.

 

[utleymu]

Any sort of shield that will deflect the hot air off the radiator fan will help the most for the least work.

Thanks for the tip I'll keep that in mind. I've been more focused on the heat coming off the exhaust manifold and haven't really been too concerned about the radiator heat.

I’m waiting for another NPT bung to install my temperature sensor. I'm really curious to see what my charged intake temps are. That will ultimately dictate how much effort I put into getting cooler air.

 

[Dougal]

Thanks for the tip I'll keep that in mind. I've been more focused on the heat coming off the exhaust manifold and haven't really been too concerned about the radiator heat.

I’m waiting for another NPT bung to install my temperature sensor. I'm really curious to see what my charged intake temps are. That will ultimately dictate how much effort I put into getting cooler air.

The exhaust manifold doesn't matter, it's ambient air temp into the air filter that's the big problem. Gain 30C and you've lost 10% of air density. Gain 60C (easy to do with hot air off the radiator) and you've got turbo intake conditions worse than gaining 2000m altitude. Losing 20% intake air density. It makes turbo performance really suck.

Intercooler can't fix the problems caused by high intake temps and isn't necessary at the boost levels that your engine will survive at. Making up a shield to direct away the radiator air and feed fresh air to that filter is your most important step.

 

[utleymu]

The exhaust manifold doesn't matter, it's ambient air temp into the air filter that's the big problem. Gain 30C and you've lost 10% of air density. Gain 60C (easy to do with hot air off the radiator) and you've got turbo intake conditions worse than gaining 2000m altitude. Losing 20% intake air density. It makes turbo performance really suck.

Intercooler can't fix the problems caused by high intake temps and isn't necessary at the boost levels that your engine will survive at. Making up a shield to direct away the radiator air and feed fresh air to that filter is your most important step.

Appreciate the insight. If I understand correctly, although an intercooler will help cool and densify the air before it gets to the engine's intake, the initial hot air at the turbo's intake will cause the turbo itself to be less efficient. Is that accurate? Or is it that an intercooler won't be able to efficiently cool the air enough to compensate for both compression (from turbo) and the initial elevated temperatures (from engine bay intake)?

 

[Dougal]

Appreciate the insight. If I understand correctly, although an intercooler will help cool and densify the air before it gets to the engine's intake, the initial hot air at the turbo's intake will cause the turbo itself to be less efficient. Is that accurate? Or is it that an intercooler won't be able to efficiently cool the air enough to compensate for both compression (from turbo) and the initial elevated temperatures (from engine bay intake)?

Yes, hot intake air makes the turbo slow to spool, chokes early, reduces efficiency and increases turbine loads and engine cooling loads too. It's bad all round.

Imagine you're slugging up a hill, your radiator fan is throwing 60C air at your intake, this reduces density enough that your normal 2.4L engine only has the air flow of a 2 litre engine. Turbo is working harder and at worse efficiency, turbine needs to work harder so drive pressure increases which further reduces engine air-flow.

Intercooler can only take some heat from the boost into the engine. It can't compensate for poor intake conditions.

 

[allochris]

Hello, just wondering if you've got some updates to share about tuning your new setup over the last couple months. How much boost does it use, with the stock unmodified pump? Uphill impression compared to stock?

I'm about to pull the triggers on either a Garrette GBC17-250 or a Kinugawa TD04-13T, just not sure which one... (Did some theoretical calculations & plotted these map...any comments about the potential surge area at low <1600RPM?

My question is, what size wastegate actuator spring should I order (7 or 14 psi?)

Also on my 2002 Dyna cab-over with a 5L, I want to know how much space/gap you have between your turbo & the right frame rail, using the center port HD Automotive exhaust manifold.

I've found 3 options:
-SPA Turbo 5L manifold (angled backward)
-HD Automotive 3rd port exhaust manifold
-HD Automotive center port exhaust manifold.

I have a A/C compressor mounted in the front right. Just wondering which manifold designs would give me the best space to fit one of the two turbos described above.

 

[Dougal]

Hello, just wondering if you've got some updates to share about tuning your new setup over the last couple months. How much boost does it use, with the stock unmodified pump? Uphill impression compared to stock?

I'm about to pull the triggers on either a Garrette GBC17-250 or a Kinugawa TD04-13T, just not sure which one... (Did some theoretical calculations & plotted these map...any comments about the potential surge area at low <1600RPM?

My question is, what size wastegate actuator spring should I order (7 or 14 psi?)

Also on my 2002 Dyna cab-over with a 5L, I want to know how much space/gap you have between your turbo & the right frame rail, using the center port HD Automotive exhaust manifold.

I've found 3 options:
-SPA Turbo 5L manifold (angled backward)
-HD Automotive 3rd port exhaust manifold
-HD Automotive center port exhaust manifold.

I have a A/C compressor mounted in the front right. Just wondering which manifold designs would give me the best space to fit one of the two turbos described above.

View attachment 3759381

View attachment 3759382

Looks far too big. You aren't going to need more than PR2 and you want the midrange to coincide with the best efficiency islands.
How are you calculating VE, temperature, intake pressure etc?

 

[bj70bc]

you want a higher rated wastegate spring than you would think, a bit higher is better to get you what you want

 

[allochris]

you want a higher rated wastegate spring than you would think, a bit higher is better to get you what you want

My first scepticism of my calculation is based on the very surprisingly low VE of 52%, based on 2985cc & 90hp@4000rpm (Toyota 5L – Engine Specs - https://www.engine-specs.net/toyota/5l.html), calculated from here: Engine Volumetric Efficiency Calculator - StrikeEngine - https://strikeengine.com/engine-volumetric-efficiency-calculator/

After that I made a table and plugged in the Pressure Ratio (1, 1.5, 2, 2.5, 3) against RPM (800, 1600, 2400, 3200, 4000) into this calculator (Turbo Size Calculator - Find CFM & Pressure Ratio - StrikeEngine - https://strikeengine.com/turbo-size-calculator-find-cfm-pressure-ratio/) to obtain Lb/min numbers, so they can be plotted on the compressor map x-axis.

i.e. 10lb/min from using PR of 2 against 2400rpm

So if my calculation done above is correct, both plots do show GBC17-250 & TD04-13T to be a tag too big for the 5L when surging below 1600pm.

Out of curiosity, I understanding 5L doesn't have a throttle plate, but if we were to keep using these bigger than ideal turbos, would installing a blowoff valve between intercooler & intake be capable to open via some sort of vaccum line and release the excess pressure generated post-turbo that can't be breath/utilized from the engine combusion at those low rpms?

 

[utleymu]

Hello, just wondering if you've got some updates to share about tuning your new setup over the last couple months. How much boost does it use, with the stock unmodified pump? Uphill impression compared to stock?

I'm about to pull the triggers on either a Garrette GBC17-250 or a Kinugawa TD04-13T, just not sure which one... (Did some theoretical calculations & plotted these map...any comments about the potential surge area at low <1600RPM?

My question is, what size wastegate actuator spring should I order (7 or 14 psi?)

Also on my 2002 Dyna cab-over with a 5L, I want to know how much space/gap you have between your turbo & the right frame rail, using the center port HD Automotive exhaust manifold.

I've found 3 options:
-SPA Turbo 5L manifold (angled backward)
-HD Automotive 3rd port exhaust manifold
-HD Automotive center port exhaust manifold.

I have a A/C compressor mounted in the front right. Just wondering which manifold designs would give me the best space to fit one of the two turbos described above.

View attachment 3759381

View attachment 3759382

Hey! Sorry for the radio silence, but I’ve been running the truck with the turbo setup for a few months now, and it’s been a game changer. I’m at about 14-15 psi with a manual boost controller, turned the fuel screw in slightly under one full turn, and I’m still running without a boost compensator. EGTs are low, and there’s no visible smoke unless I really stomp on it after a shift, then I'll get a little puff before boost kicks in. Boost kicks in immediately with this smaller turbo, and the performance difference is huge. The truck feels entirely transformed—while it’s not a rocket, I’m no longer losing speed on every incline. I can now actually accelerate uphill, pass slower trucks, and keep up with traffic, without being full throttle on the highway. It’s incredible how much it improved drivability.

As for turbo choice, I’m using the GBC17, which barely fits. The HD Auto center mount manifold had to be modified to get the compressor to fit without interference above or with the tire well. I think you're going to struggle to fit anything larger, especially with an AC compressor. The manual gear shifter linkages eat up a lot of space; the Toyota engineers really took full advantage of that entire area. My setup is pretty much threaded in there like a needle, with minimal clearance around multiple components. Only one minor modification to the linkage was required. If you're going to keep the AC I would think more significant modifications are going to need to be made to move the turbo back a little bit.

I’d also suggest a manual boost controller, whatever wastegate spring you go with, so you can fine-tune the boost.

 

[utleymu]

On another note, I’m planning to pick up a welder this winter and try my hand at fabricating a snorkel. While the setup has been solid thus far, I want to really dial in the less than ideal intake situation for long-term reliability. Never welded before, so we'll see how it goes!

I'm toying with two possible routes for the snorkel. Space is the main constraint, so any advice on ideal tubing size? Can I get by with 2.5” tubing, or is 3” a must? Also, would it make sense to use 3” on the exterior where there is plenty of room and 2.5” in the tighter run right to the turbo, or should I stick to one size?

The other thing I want to dial in is the breather hose situation. I'm currently running to atmosphere, but would like to get some vacuum on it and avoid the fumes under cabin. Again, because of space, I'm not really able to plumb it the intake, post air filter pre turbo. I'm instead considering plumbing it to an exhaust venturi. I've read mixed reviews about this on here, curious if anyone has thoughts.

 

[Dougal]

My first scepticism of my calculation is based on the very surprisingly low VE of 52%, based on 2985cc & 90hp@4000rpm (Toyota 5L – Engine Specs - https://www.engine-specs.net/toyota/5l.html), calculated from here: Engine Volumetric Efficiency Calculator - StrikeEngine - https://strikeengine.com/engine-volumetric-efficiency-calculator/
View attachment 3760030

After that I made a table and plugged in the Pressure Ratio (1, 1.5, 2, 2.5, 3) against RPM (800, 1600, 2400, 3200, 4000) into this calculator (Turbo Size Calculator - Find CFM & Pressure Ratio - StrikeEngine - https://strikeengine.com/turbo-size-calculator-find-cfm-pressure-ratio/) to obtain Lb/min numbers, so they can be plotted on the compressor map x-axis.

i.e. 10lb/min from using PR of 2 against 2400rpm
View attachment 3760048

So if my calculation done above is correct, both plots do show GBC17-250 & TD04-13T to be a tag too big for the 5L when surging below 1600pm.

Out of curiosity, I understanding 5L doesn't have a throttle plate, but if we were to keep using these bigger than ideal turbos, would installing a blowoff valve between intercooler & intake be capable to open via some sort of vaccum line and release the excess pressure generated post-turbo that can't be breath/utilized from the engine combusion at those low rpms?

That's a petrol/gasoline engine VE calculator that won't work for diesel. I would use 90% VE for max torque and 80% for max power. Recalculate with those. PR2 is your maximum. I wouldn't go past 10-12psi on an engine not designed to be turbocharged.

Turbo sizing is everything. It's not possible to vent your way around incorrect sizing.

Hey! Sorry for the radio silence, but I’ve been running the truck with the turbo setup for a few months now, and it’s been a game changer. I’m at about 14-15 psi with a manual boost controller, turned the fuel screw in slightly under one full turn, and I’m still running without a boost compensator. EGTs are low, and there’s no visible smoke unless I really stomp on it after a shift, then I'll get a little puff before boost kicks in. Boost kicks in immediately with this smaller turbo, and the performance difference is huge. The truck feels entirely transformed—while it’s not a rocket, I’m no longer losing speed on every incline. I can now actually accelerate uphill, pass slower trucks, and keep up with traffic, without being full throttle on the highway. It’s incredible how much it improved drivability.

As for turbo choice, I’m using the GBC17, which barely fits. The HD Auto center mount manifold had to be modified to get the compressor to fit without interference above or with the tire well. I think you're going to struggle to fit anything larger, especially with an AC compressor. The manual gear shifter linkages eat up a lot of space; the Toyota engineers really took full advantage of that entire area. My setup is pretty much threaded in there like a needle, with minimal clearance around multiple components. Only one minor modification to the linkage was required. If you're going to keep the AC I would think more significant modifications are going to need to be made to move the turbo back a little bit.

I’d also suggest a manual boost controller, whatever wastegate spring you go with, so you can fine-tune the boost.

15psi on a high compression IDI engine will be very hard on your crank. Remember these engines were never designed to be turbocharged.

 

[allochris]

That's a petrol/gasoline engine VE calculator that won't work for diesel. I would use 90% VE for max torque and 80% for max power. Recalculate with those. PR2 is your maximum. I wouldn't go past 10-12psi on an engine not designed to be turbocharged.

Turbo sizing is everything. It's not possible to vent your way around incorrect sizing.



15psi on a high compression IDI engine will be very hard on your crank. Remember these engines were never designed to be turbocharged.

Thank you all for the input. I've recalculated by using VE of 0.9 (not calculated this time) & plotted the points again on these 2 turbos:

On a 2985cc (5L), the GBC-17 seems to choke at 4000rpm while the TD04 is still within its max choke limit.

Just based on these 2 plots alone, what can we conclude on? The points seems to land on the TD04 efficiency island a bit nicer, maybe it's because it's slightly bigger?

 

[Dougal]

TD04-13T compressor is looking good. What turbine size is available?

 

[KiwiDingo]

Boost doesn't hurt these IDI diesel engines, too much fuel does. I've seen soo many IDI engines killed because they weren't running enough boost.

 

[allochris]

KiwiDingo: So high boost over PR 2 doesn't hurt stock Idi internals even at 22.2:1 compression ratio?

Dougal: The Kinugawa-13T (Kinugawa Turbo 2.4" TD04L 13T/15T 5cm T25 4-Bolt IWG TOYOTA DTS Hilux - https://store.kinugawaturbosystems.com/products/24-td04l-13t15t-5cm-t25-4bolt-iwg-dtshilux?variant=42034211848446) I'm looking at is spec'ed with: Compressor 40.3/56 & Turbine 47/41.3 @ 0.33a/r (versus GBC17-250 Compressor 36/49 @ 0.52a/r & Turbine 44/40 @ 0.5a/r)

They also have another one (Kinugawa Turbo 2.4" TD04L-13T T25 SAAB Conic Outlet Internal Wastegate - https://store.kinugawaturbosystems.com/products/kinugawa-turbo-2-4-td04l-13t-t25-saab-conic-outlet-internal-wastegate?variant=32814148386900) specs for 2L/3L with 3 options of a/r @ 0.33/0.41/0.49 as well. (TBH, I'm not too sure what's a good a/r # to select.)

Utleymu: Thanks for the driving feedback & the tip to use a manual boost controller to fine-tune.

-How many lbs spring is inside your GBC17-250 actuator? (i.e. 7psi?).

-You've mentioned turning in the fuel screw for 1 turn. Is that the 5mm allen set screw? The fsm (page EG134) says injection volume increase about 3cc per 1/2 turn.
-How you are determining how much fuel to add? Just by looking at EGT (<1200F) & no black smoke while driving? I've been thinking of installing a AFR gauge (i.e. https://www.justraceparts.com.au/spartan-3d-diesel-wideband-air-fuel-ratio-gauge) about 1 meter downstream from turbo to measure & tune AFR above 20:1.
-Would you have a picture showing a top view of your modified HD center port exhaust manifold bolted with the turbo? I'd like to see what modification you've made, layout, and surrounding clearance etc.
-Breather hose of which component are you referring to?


I've included below a compressor map using Garrett GBC17-250 & 0.9 VE for the 3L (2776cc). When reving at 4K rpm, this turbo seems to be slightly less choky on a 3L, than the 5L (notice at PR1.5, it's right on the choke limit).

 

[KiwiDingo]

Correct, boost alone doesn't hurt. The fuelling and timing is what hurts but people like to blame "boost" far to often. Also I don't personally consider a pressure ratio of 2 to be considered "high boost" but I also live at sea level so my conditions may be different to others.

 

[Dougal]

KiwiDingo: So high boost over PR 2 doesn't hurt stock Idi internals even at 22.2:1 compression ratio?

Dougal: The Kinugawa-13T (Kinugawa Turbo 2.4" TD04L 13T/15T 5cm T25 4-Bolt IWG TOYOTA DTS Hilux - https://store.kinugawaturbosystems.com/products/24-td04l-13t15t-5cm-t25-4bolt-iwg-dtshilux?variant=42034211848446) I'm looking at is spec'ed with: Compressor 40.3/56 & Turbine 47/41.3 @ 0.33a/r (versus GBC17-250 Compressor 36/49 @ 0.52a/r & Turbine 44/40 @ 0.5a/r)

They also have another one (Kinugawa Turbo 2.4" TD04L-13T T25 SAAB Conic Outlet Internal Wastegate - https://store.kinugawaturbosystems.com/products/kinugawa-turbo-2-4-td04l-13t-t25-saab-conic-outlet-internal-wastegate?variant=32814148386900) specs for 2L/3L with 3 options of a/r @ 0.33/0.41/0.49 as well. (TBH, I'm not too sure what's a good a/r # to select.)

Utleymu: Thanks for the driving feedback & the tip to use a manual boost controller to fine-tune.

-How many lbs spring is inside your GBC17-250 actuator? (i.e. 7psi?).

-You've mentioned turning in the fuel screw for 1 turn. Is that the 5mm allen set screw? The fsm (page EG134) says injection volume increase about 3cc per 1/2 turn.
-How you are determining how much fuel to add? Just by looking at EGT (<1200F) & no black smoke while driving? I've been thinking of installing a AFR gauge (i.e. https://www.justraceparts.com.au/spartan-3d-diesel-wideband-air-fuel-ratio-gauge) about 1 meter downstream from turbo to measure & tune AFR above 20:1.
-Would you have a picture showing a top view of your modified HD center port exhaust manifold bolted with the turbo? I'd like to see what modification you've made, layout, and surrounding clearance etc.
-Breather hose of which component are you referring to?


I've included below a compressor map using Garrett GBC17-250 & 0.9 VE for the 3L (2776cc). When reving at 4K rpm, this turbo seems to be slightly less choky on a 3L, than the 5L (notice at PR1.5, it's right on the choke limit).
View attachment 3761158

This Kingugawa is the same 13T compressor but a more active TD04 4cm turbine: Kinugawa Turbo TD04-13T 4M40T Pajero Triton Shogun Challenger 94-97 - https://store.kinugawaturbosystems.com/products/kinugawa-turbo-td04-13t-4m40t-pajero-triton-shogun-challenger-94-97
It doesn't have the T25 inlet flange though, you'd need an adapter.

Turbine sizing is tradeoff of torque vs power. On diesels I find it's always best to maximise driveability with low end torque. Turbos sized for higher rpm power just leave you changing gears all the time as they fall on their face at lower rpm.

Your AFR gauge idea is a very good one. I run one myself for tuning but remove it the rest of the time. It's configured to be standalone with a clamp on the end of the exhaust pipe and cigarett lighter power. Too much boost will make life hell for your crank, head and head-gasket and also suck power. Keeping AFR at 20 or above is very safe. How clean you run at 17-18:1 depends on how well your injectors are spraying.

 

[allochris]

This Kingugawa is the same 13T compressor but a more active TD04 4cm turbine: Kinugawa Turbo TD04-13T 4M40T Pajero Triton Shogun Challenger 94-97 - https://store.kinugawaturbosystems.com/products/kinugawa-turbo-td04-13t-4m40t-pajero-triton-shogun-challenger-94-97
It doesn't have the T25 inlet flange though, you'd need an adapter.

Turbine sizing is tradeoff of torque vs power. On diesels I find it's always best to maximise driveability with low end torque. Turbos sized for higher rpm power just leave you changing gears all the time as they fall on their face at lower rpm.

Your AFR gauge idea is a very good one. I run one myself for tuning but remove it the rest of the time. It's configured to be standalone with a clamp on the end of the exhaust pipe and cigarett lighter power. Too much boost will make life hell for your crank, head and head-gasket and also suck power. Keeping AFR at 20 or above is very safe. How clean you run at 17-18:1 depends on how well your injectors are spraying.

Dougal: That's a very smart idea making your AFR sensor removal as it's solely used for tuning (rather than full time exposing the 02 sensor to the harsh environment.) Which brand/model are you using that can also read beyond 20:1?

Utleymu: I've had a closer look at your previous posted pic. It seems like your collector tube of the HD exhaust manifold got shorten and angled flat/horizontal to allow your turbo to fit against the frame rail. Is that what I'm seeing? How much clearance is there behind your downpipe to the cab?