Small Turbo on stock L29 454?

[LC2NLS6]

Set a budget, price it all out. Do the cam, valve springs, fuel pump and tune that first. I bet that will wake it up a lot before going turbo. A good torque converter helps turbo setups a lot, and most overlooked performance mod if making power. I run PTC.

 

[SNOMAN]

Turbo BB vs dmax just depends on what you want for efficiency. Dmax will get great mileage, but they're expensive and a lot of work to swap. Turbo BB will get OK mileage if you can stay out of the throttle lol The dmax will make more torque at lower rpm, and sustain it much longer, but if you're not towing a lot the BB will do fine.

My rear mount turbo is just a gt45, but it is definitely small for the application. I think the heat loss from the turbo being 10' from the engine helps out with back pressure though, and I'm also only running 5 psi. As is back pressure is around 2:1, which is obviously higher than ideal, but could be worse. The turbo I'm running was mostly to get the system up and going, I'll upgrade it to a s475 or s480 eventually, but I need more injector and a walbro 450 first.

Currently I have a walbro 255 and 36 lb injectors ( flow ~42 at 58 psi), the injectors are maxed out at 5 psi the 255 is keeping pressure up so far but I am probably close to the max.

If you aren't planning to go much above 500 hp a walbro 255 should be enough, and a set of 36 or 42 lb injectors should work.

Stock injectors won't support much, so don't plan to use those, and I wouldn't trust the factory fuel pump personally.

Good Information. Can you PM everything you have done to your engine or do you have link to your build? Yes 500hp is plenty.

 

[SNOMAN]

Are the 42lb injectors for a LS

Turbo BB vs dmax just depends on what you want for efficiency. Dmax will get great mileage, but they're expensive and a lot of work to swap. Turbo BB will get OK mileage if you can stay out of the throttle lol The dmax will make more torque at lower rpm, and sustain it much longer, but if you're not towing a lot the BB will do fine.

My rear mount turbo is just a gt45, but it is definitely small for the application. I think the heat loss from the turbo being 10' from the engine helps out with back pressure though, and I'm also only running 5 psi. As is back pressure is around 2:1, which is obviously higher than ideal, but could be worse. The turbo I'm running was mostly to get the system up and going, I'll upgrade it to a s475 or s480 eventually, but I need more injector and a walbro 450 first.

Currently I have a walbro 255 and 36 lb injectors ( flow ~42 at 58 psi), the injectors are maxed out at 5 psi the 255 is keeping pressure up so far but I am probably close to the max.

If you aren't planning to go much above 500 hp a walbro 255 should be enough, and a set of 36 or 42 lb injectors should work.

Stock injectors won't support much, so don't plan to use those, and I wouldn't trust the factory fuel pump personally.

Are the 42lb injectors for a LS3/LS7? Sorry I am unfamiliar as to what injectors will swap out.

 

[618 Syndicate]

The problem with not enough injector is the risk of catastrophic failure from pushing the efficiency too far. As you approach 100% duty cycle the likelihood of failure increases dramatically, and an injector locking closed at high boost/rpm will melt **** fast. Hung open is bad as well, but lean conditions put windows in **** that don't need windows. Like pistons and blocks.
Too much injector is harder to tune for part throttle driveability, so be careful on that end as well.

 

[LC2NLS6]

Back in the day, when I ran out of injector and had no money, I just cranked up the base fuel pressure to 51-55 psi from 43 psi, vac line off the regulator. Still went 100% duty cycle, but more boost...

 

[LC2NLS6]

A very helpful mod when going for boost, logging - log the fuel pressure. Well, first verify the electric fuel pressure gauge is as accurate or note what it is, vs a mechanical one, then take mechanical fp gauge off.

 

[Christian Steffen]

Are the 42lb injectors for a LS


Are the 42lb injectors for a LS3/LS7? Sorry I am unfamiliar as to what injectors will swap out.

I'm not sure what they came out of, something ford I believe. There are other options out there with the use of spacers too, but i haven't dug too far into that. If you google 42 lb green top injectors you should find something.

As far as my engine goes, its a 489 stroker, scat crank, eagle forged rods and mahle forged pistons (9.6:1 cr).

This cam:
https://www.compcams.com/xtreme-ene...ic-roller-cam-chevrolet-big-block-gen-vi.html

Stock intake manifold.

For fuel pressure monitoring I have a sensor hooked to the rail wired through my egr sensor plug, then fed into hp tuners. I'll probably add a mech gauge on the dash for safeties sake eventually.

 

[618 Syndicate]

Back in the day, when I ran out of injector and had no money, I just cranked up the base fuel pressure to 51-55 psi from 43 psi, vac line off the regulator. Still went 100% duty cycle, but more boost...

100% duty cycle is one of those things that is fine right up until it's not. Yes, you can up the fuel pressure to compensate for fuel needs (basically what an fmu does) but there's no escaping injector lock. All it takes is one.

But you already know this. I do like how much the turbo game has changed over the last 10 years or so, especially the cost of injectors and engine management. It's way easier and cheaper to boost **** now.

 

[LC2NLS6]

Yeah back in 2002 I was running 10's and almost beating everything at the track (Bandimere, CO), when the DA was 10,000 ft I smoked liter bikes and they were not happy about that lol. My C5 z06 barely ran low 13's at that altitude. Turbo solves a lot of that. Nowadays you can get a full turbo kit for an LS truck for about $3k. I had some oddball Accel 48# injectors a buddy gave me to test his chips. I had those things maxed out for sure at 130 mph in the 1/4 on a V6.

If you want full control, Holley Terminator X has the built in 4L80E/60 trans controller too. I wish I had done that instead of sticking with my Sniper. Maybe on the next truck...I run Holley HP on the race car.

 

[Erik the Awful]

Turbos are like camshafts. The price difference for going larger is negligible. The cost is in what you have to do to everything else to support it. Build to the level you're comfortable spending, and they buy the biggest turbo that will safely run with your combination.