Hey everybody, so those of you have been around this site for a while may have seen my last iteration of this car which had a small block 350 with twin gt35s and a 200-4r transmission. While fun, I was getting sick of calibrating the carb and trying to find usable junk yard small blocks that seem to be getting harder and harder to find in my area.

So the natural solution to these problems is the LS, and behind it a 4l80e. I don't have a block yet but I am going to look at a rebuilt 4l80e this weekend. at this point, I'm just looking for pointers and mistakes people have made in the past before I go and buy anything.

However, my main question is what I should go with regarding a harness, ecu, and tcu. I have a solid understanding of most the sensors and their functions on a stock LS, but from what I have read different aftermarket harnesses/ ecus don't require all the same sensors to function. For the price, microsquirt seems like an effective and simple option, but I'd like to know which sensors I'd need to keep, upgrade (like the MAP), or get rid of. I feel like that if I were go microsquirt with the motor I'd do the same for the trans, and would these need to be mated somehow?

Another alternative seems to be getting a stock harness, modifying it, and getting a stock ECU and having it tuned. While this seems more involved, I have plenty of time and with a good guide I could probably get it done relatively quickly.

I should probably add that the car won't have power steering, AC, etc and I'm also trying to keep this as cheap as possible. even though I've been reading a ton about this stuff I still apologize for the huge lack of knowledge, it's starting to seem like have an engine and transmission in front of me while I'm looking this stuff up would make everything more clear. And thanks in advance for any help!

 

Bump!!

 

Needed sensors:

Wideband
IAT
CLT
TPS
MAP

Edit* For an LS, you'd need the crank and or cam sensors too

 

Try to grab the engine from a JY with all the sensors in place. I can't really see needing/wanting a 4l80e personally. They are heavy/expensive/rob lots of power/ and require computer control. Should be able to gear/tire car tall enough to get away with a glide or th400 depending on weight. Will be much more reliable, cheap, cost effective. I'm going over 60 @ 2300rpm and knocking off 8 second passes at the strip with a glide. You can easily run a 2.73 gear if you want more of a cruiser. A turbo LS will pull it no problem. You really don't need/want a 4.10 gear in a turbo car.

Depending on what you want/need I'd look to the plug and play megasquirt boxes.

This one comes with the 80lb injectors and plugs into all your factory sensors. Buying the kit with the injectors saves you about $55 over buying the injectors separately.

They also have plug and play versions with trans control if you decide you want the 4L80e.

http://www.efisource.com/shop/package-ls-gold-box/

This is also a newer option with some extra bells and whistles if you want a fancy intake. I'm not familiar with it though. The MS3 box has tons of extra go fast goodies on it I don't see listed for this unit. (boost control, traction control, anti-lag, tons of inputs/outputs etc...) This looks like a dolled up micro squirt IMO.

http://fitechefi.com/fitech-uploads/2016/07/LSMini6-panel 10-20-16.pdf


Awesome car BTW!

 

Thanks for the input, helpful as always! I'm talking to a guy trying to get a TH400, and I think I'm going with the simple microsquirt harness/ computer for now because at this point I really don't need all the bells and whistles, I just want a running turbo LS haha. I'll try to get a motor this week too, and once I have those I'll order the harness.

If anybody would recommend getting anything else/ changing the order I'm doing things let me know! Always looking. For suggestions.

 

May contact Stacey Moore on this site. If he is still in the microsquirt business, he was selling the micro with harness kit for around $500 ready to go. I used one of his kits on my 280z it worked great.

 

I'll look into it, just picked up a nice clean 2.73 8.8 rear end from a mustang, aka the same thing I have in the car currently with a better ratio for no OD. Talking to a guy about a TH400 he has so I'll probably get that this week too.

Also, got quoted 200 for a 4.8 and 350 for 5.3 (obviously no harness etc) what would you go with? I'm leaning towards the 5.3 just because more tunes seem to be available for turbo 5.3s, but as always look for suggestions/ advice

 

Depends on the year. If they are gen3 motors the 4.8 is stronger, I’d go that route. Don’t worry about the tune, they will be almost interchangeable.

Don’t shy away from a 4.8. They can be power houses in light weight cars and no one wants them. I’d look for a gen4 (2005+) 4.8. It will require the least amount of work and be the cheapest of the gen4 engines. None of them came with the Drive on Demand or adjustable timing (that I know of) like the newer 5.3’s did so they are easier to install as well. Smaller engine allows you to squeak a little more out of the turbos too. They also have a higher redline which works better with cheaper converters. They do take about 300 more rpm to make the same power as a 5.3 across the board. So run a slightly loose converter (PTC’s budget 10” for $450 would be my choice). They will bolt directly in with no modification to an LS flywheel with a TH400. Just let the PTC guys know the engine/trans/gears combo and they will setup the converter pad spacing and stall range. Toss a mild cam profile in that will make power to 7k and it will be a fun little screamer.

 

So I picked up a 2000 5.3 out of a suburban with ~130k. Haven't pulled the heads yet but the motor was running fine when pulled with no noises so I'm hopeful.

I know the converter is a worth while investment and I wasn't too sure where to start as far as stall speeds, by slightly loose would you mean like 2500-3000 stall? The converter was the Achilles heal of my last build so I want to get it right this time around.

I'm also familiarizing myself with tuner studio in advance so when I pick up the microsquirt I'll be ready to tune everything. With the motor all taken apart I know I really should replace the cam and it's not a huge cost but I'm really trying to save cash anywhere I can and at least for the time being I'm pretty sure I'll be satisfied with the power output with the stock cam on 13-15psi. Plus until I get some wider tires/wheels more power won't really do much except make for smokier burnouts haha.

Anyway finals are over for me next week then I can really dig into the motor and get it dressed up and ready, at least for the time being I'm trying to have this thing ready for summer but I still have to replace the entire drivetrain, fuel system, and wire everything up.... build quality is also going to improve this time around because I don't want to be heading to the junkyard once a month for another block haha. Excited to start wrenching again though, it's definitely an addiction

 

So I picked up a 2000 5.3 out of a suburban with ~130k. Haven't pulled the heads yet but the motor was running fine when pulled with no noises so I'm hopeful.

I know the converter is a worth while investment and I wasn't too sure where to start as far as stall speeds, by slightly loose would you mean like 2500-3000 stall? The converter was the Achilles heal of my last build so I want to get it right this time around.

I'm also familiarizing myself with tuner studio in advance so when I pick up the microsquirt I'll be ready to tune everything. With the motor all taken apart I know I really should replace the cam and it's not a huge cost but I'm really trying to save cash anywhere I can and at least for the time being I'm pretty sure I'll be satisfied with the power output with the stock cam on 13-15psi. Plus until I get some wider tires/wheels more power won't really do much except make for smokier burnouts haha.

Anyway finals are over for me next week then I can really dig into the motor and get it dressed up and ready, at least for the time being I'm trying to have this thing ready for summer but I still have to replace the entire drivetrain, fuel system, and wire everything up.... build quality is also going to improve this time around because I don't want to be heading to the junkyard once a month for another block haha. Excited to start wrenching again though, it's definitely an addiction

 

Converters that are rated as "X" stall RPM are bogus. Put a "3000 stall" behind 300hp and then 1000hp engine. Stall speed will vary a ton. Weight and gearing also play a roll. Just call PTC and tell them about your combo and how you want it to act. Just be honest about the power it makes and you'll be fine. Their $450 10" converter is a great unit. Best budget converter around IMO. Th 9.5" is even better but will run you $1000ish.

As far as the cam goes I really wouldn't waste your time with the OEM truck cam. Look for a Stock used LS1 cam of any year. Think I paid $25 for my last one at a swap meet. They are great for a budget cam. Will pick up quite a bit of the the truck grind anyway.

 

Ill definitely give them a call and thanks for the heads up on the LS1 cam, for ~25 bucks there's no reason not to toss it in

 

Spend some good $ on a converter it will be well worth it. I had a $500 converter in my car and it was fine on low boost but once the boost was raised it was flashing up to like 6000 RPM vs the 3000 it flashed to on low HP.

 

Hmm okay I'll be generous with the expected HP numbers when I'm talking to the PTC guys, thanks for the heads up.

On another note just out of curiosity, has anyone else ran GT35s on a 5.3 before on here? I know the chances of all the variables contributing to spool time being the same (cam etc) are quite low but I'm just looking for a ballpark. With the 350 small block, MILD cam and chinese aluminum heads it reached boost right around 3k which I loved for the street manners when driving casually.



I'll get some pictures up the motor etc as I get it cleaned up this weekend, also planning on shaving the truck intake because I have way more time than cash coming up on break and with some patience I'll make it look pretty decent until I upgrade in the future.

 

Do you know what wheel sizes your "GT35s" are? I know there are several. The 61mm compressor versions made about 700whp whp on a buddies 5.3 and spooled very well.

 

Hahaha yeah good point the Chinese ones can be iffy on the sizing but I've measured, they're 61s. But man 700 is a ton of power, when I get this put together I'm really gonna need to keep it turned down until I get a new set of wheels/ tires... the show wheels that were on there only have 215 ET streets which even on the old setup (~400-450hp) they'd light up. I'm probably gonna wait to buy a new set until these tires are toast which probably won't take that long haha...

Related to that I was thinking about going with some 275/50/15 R888s- seems like a lot of guys in that power range are running a similar setup. I know surface area touching the ground doesn't make the biggest difference compared to different compounds but you guys think these would behave somewhat well when you roll into it?

 

That was the CXracing 61mm gt35’s. Decent cam, 243heads, ported LS2 intake, E85, intercooled, and really leaning on them. But yea 700 (think it was closer to 740whp) would be nutty at your weight. Those are Dynojet numbers which are usually pretty generous with turbo cars.

Great tire for “rolling into it” on the street are the Nitto 555r’s. They are a harder compound and won’t wad up/feather like the ET streets and softer drag radials do on the street. Also last 3x longer. Couple 1200+whp street racer guys actually prefer them over the softer compound stuff and have VBOX times proving they perform better form 40-160+mph (on the street) As far as dead hooking at the track the ET streets or the even softer pro series MT sells are the way to go.

Something like you’ve built will really require some sort of progressive boost control/power management if you wanted to run big power IMO. Even my 3100lb whale will smoke the tires over 12lbs if I just romp on the gas cruising at 40mph. That’s in hi-gear with a 3.25 in the rear and a 30” drag radial. Need a way to limit power for 2-3 seconds right when the turbos spool up. Since adding progressive boost control on the MS3 I can run 20lbs on the street with a 275 drag radial no problem. (Right around 1000 crank HP going by weight and trap speed at the drag strip)

 

Interesting. With the microsquirt do you think pulling a few degrees of timing as it comes into boost would help?

 

Yup, anythign you can do to limit power as boost hits initially will help. Not sure you'll be able to limit it enough that way... but it might help at low power levels.

 

Agreed. The 555's were my "street" tire, I preferred the way the M/T's would grab but they just don't last and were super sketchy in the wet. On the other side of that coin, I couldn't get the 555's to hook worth a damn at the track. If I were going to do it again, I'd just do a sacrificial, regular radial tire for the street, they wouldn't grab real well but they're cheaper and better if you get stuck in some weather.