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So I've always wanted a turbo project. After helping my son out with his Turbo Iron Duke, the potential is impressive.
This winter I found an unfinished 1990 Iroc with a 305 5 speed 4 wheel disc setup , with Cxracing turbo kit. While it was all installed, it didn't run. Long story short ... I re-did the entire installation, fixed things I didn't like, and installed proper injectors (there were low impedance ones installed!). Still lots of cleanup and such ... but it's in the works.
For tuning, here is what I did. I installed 38lb injectors (2x the stock 305) ... and I just happened to have a set of new ones in a box. Figure 14PSI would need 2X the fueling :-). In the BIN, I left the fuel injector constant, but "halved" all the VE tables. Installed a GM 2 bar map. And recalibrated the MAP, Spark and all other MAP references to the new range. Ok, so most things work, but a few don't. The key for me was having the ability to add 2X the fuel under full boost given the stock BIN limitations.
So test results. Its runs! Took a few instances to get some bugs sorted out. For now, Open loop works well. Closed loop does not ... the narrow band heated O2 does not give correct values as compared to what the wideband does. The narrow band is right after the turbo, and the wideband is a ways down. For now ... I am just tuning open loop ... closed just ran it too lean everywhere. And the BLM Cell change were too erratic for a stable idle. I tried a few version of RPM and MAP setting ... but pushed that work out to a later date.
The MAP table as is ... is pretty small for 0-100 kpa which is now 0-50 kpa. For the most part, I will always be on the rich side of any calibration.
The Spark table suffers the same limitations. So you can have a decent spark table, but for decel and part cruise, you make compromises. Still work to do here. I am being very conservative on the timing while in boost - I feel there is room to tune there ... with better gas.
Now the fun ... Yep it's got boost! I've put in a basic 6PSI wastegate spring, and dialed up the adjuster so the car sees 7.5-8.5 PSI. Boost starts around 2800 and is all in by 4200. With premium, I only see 1 or 2 spark knocks during a WOT run. It pretty cool around here ... so the hot days of summer may yield different results.
The seat of the pants ... THIS IS FREAKEN AWESOME! The turbo feeds the engine air all the time, so even when there is no boost, the turbo is helping by providing air. Regular driving, the engine is much more crisp and free-er reving compared to no turbo. Under boost, it picks up the nose of the car and pushes you in your seat.
The VE table tuning is interesting. You can see some of the limitations of the long tube runners as the VE numbers start to level off from linear. So the engine is just less efficient so to speak.
Future plans??? Well I will move over to s_aujp and see if I can do some better fine tuning. I knew my approach was brute force and ignorance ... but I was up for it.
Also have to keep a look out for an intercooler ... help with summer heat.
Fun Facts ... the car was an AC car, so I repinned the ECM to give me control of the 2nd fan. Works well and help with all that underhood heat. Also connected in a true intake air temp sensor to the Oil Temp sensor pin on the 7730. It works! I am using a non-brass ar temp sensor as they are much faster vs. the TPI MAT sensor which is snail slow. So I can data log intake temps along with spark knock and such. Can't do much else with it ... but data is good.
So I've always wanted a turbo project. After helping my son out with his Turbo Iron Duke, the potential is impressive.
This winter I found an unfinished 1990 Iroc with a 305 5 speed 4 wheel disc setup , with Cxracing turbo kit. While it was all installed, it didn't run. Long story short ... I re-did the entire installation, fixed things I didn't like, and installed proper injectors (there were low impedance ones installed!). Still lots of cleanup and such ... but it's in the works.
For tuning, here is what I did. I installed 38lb injectors (2x the stock 305) ... and I just happened to have a set of new ones in a box. Figure 14PSI would need 2X the fueling :-). In the BIN, I left the fuel injector constant, but "halved" all the VE tables. Installed a GM 2 bar map. And recalibrated the MAP, Spark and all other MAP references to the new range. Ok, so most things work, but a few don't. The key for me was having the ability to add 2X the fuel under full boost given the stock BIN limitations.
So test results. Its runs! Took a few instances to get some bugs sorted out. For now, Open loop works well. Closed loop does not ... the narrow band heated O2 does not give correct values as compared to what the wideband does. The narrow band is right after the turbo, and the wideband is a ways down. For now ... I am just tuning open loop ... closed just ran it too lean everywhere. And the BLM Cell change were too erratic for a stable idle. I tried a few version of RPM and MAP setting ... but pushed that work out to a later date.
The MAP table as is ... is pretty small for 0-100 kpa which is now 0-50 kpa. For the most part, I will always be on the rich side of any calibration.
The Spark table suffers the same limitations. So you can have a decent spark table, but for decel and part cruise, you make compromises. Still work to do here. I am being very conservative on the timing while in boost - I feel there is room to tune there ... with better gas.
Now the fun ... Yep it's got boost! I've put in a basic 6PSI wastegate spring, and dialed up the adjuster so the car sees 7.5-8.5 PSI. Boost starts around 2800 and is all in by 4200. With premium, I only see 1 or 2 spark knocks during a WOT run. It pretty cool around here ... so the hot days of summer may yield different results.
The seat of the pants ... THIS IS FREAKEN AWESOME! The turbo feeds the engine air all the time, so even when there is no boost, the turbo is helping by providing air. Regular driving, the engine is much more crisp and free-er reving compared to no turbo. Under boost, it picks up the nose of the car and pushes you in your seat.
The VE table tuning is interesting. You can see some of the limitations of the long tube runners as the VE numbers start to level off from linear. So the engine is just less efficient so to speak.
Future plans??? Well I will move over to s_aujp and see if I can do some better fine tuning. I knew my approach was brute force and ignorance ... but I was up for it.
Also have to keep a look out for an intercooler ... help with summer heat.
Fun Facts ... the car was an AC car, so I repinned the ECM to give me control of the 2nd fan. Works well and help with all that underhood heat. Also connected in a true intake air temp sensor to the Oil Temp sensor pin on the 7730. It works! I am using a non-brass ar temp sensor as they are much faster vs. the TPI MAT sensor which is snail slow. So I can data log intake temps along with spark knock and such. Can't do much else with it ... but data is good.
So ... long story.
Cheers!
Mark.
Tuned one using $59 years ago. Supercharged 350 TPI in a former 4.3 powered Typhoon.
So I've always wanted a turbo project. After helping my son out with his Turbo Iron Duke, the potential is impressive.
This winter I found an unfinished 1990 Iroc with a 305 5 speed 4 wheel disc setup , with Cxracing turbo kit. While it was all installed, it didn't run. Long story short ... I re-did the entire installation, fixed things I didn't like, and installed proper injectors (there were low impedance ones installed!). Still lots of cleanup and such ... but it's in the works.
For tuning, here is what I did. I installed 38lb injectors (2x the stock 305) ... and I just happened to have a set of new ones in a box. Figure 14PSI would need 2X the fueling :-). In the BIN, I left the fuel injector constant, but "halved" all the VE tables. Installed a GM 2 bar map. And recalibrated the MAP, Spark and all other MAP references to the new range. Ok, so most things work, but a few don't. The key for me was having the ability to add 2X the fuel under full boost given the stock BIN limitations.
So test results. Its runs! Took a few instances to get some bugs sorted out. For now, Open loop works well. Closed loop does not ... the narrow band heated O2 does not give correct values as compared to what the wideband does. The narrow band is right after the turbo, and the wideband is a ways down. For now ... I am just tuning open loop ... closed just ran it too lean everywhere. And the BLM Cell change were too erratic for a stable idle. I tried a few version of RPM and MAP setting ... but pushed that work out to a later date.
The MAP table as is ... is pretty small for 0-100 kpa which is now 0-50 kpa. For the most part, I will always be on the rich side of any calibration.
The Spark table suffers the same limitations. So you can have a decent spark table, but for decel and part cruise, you make compromises. Still work to do here. I am being very conservative on the timing while in boost - I feel there is room to tune there ... with better gas.
Now the fun ... Yep it's got boost! I've put in a basic 6PSI wastegate spring, and dialed up the adjuster so the car sees 7.5-8.5 PSI. Boost starts around 2800 and is all in by 4200. With premium, I only see 1 or 2 spark knocks during a WOT run. It pretty cool around here ... so the hot days of summer may yield different results.
The seat of the pants ... THIS IS FREAKEN AWESOME! The turbo feeds the engine air all the time, so even when there is no boost, the turbo is helping by providing air. Regular driving, the engine is much more crisp and free-er reving compared to no turbo. Under boost, it picks up the nose of the car and pushes you in your seat.
The VE table tuning is interesting. You can see some of the limitations of the long tube runners as the VE numbers start to level off from linear. So the engine is just less efficient so to speak.
Future plans??? Well I will move over to s_aujp and see if I can do some better fine tuning. I knew my approach was brute force and ignorance ... but I was up for it.
Also have to keep a look out for an intercooler ... help with summer heat.
Fun Facts ... the car was an AC car, so I repinned the ECM to give me control of the 2nd fan. Works well and help with all that underhood heat. Also connected in a true intake air temp sensor to the Oil Temp sensor pin on the 7730. It works! I am using a non-brass ar temp sensor as they are much faster vs. the TPI MAT sensor which is snail slow. So I can data log intake temps along with spark knock and such. Can't do much else with it ... but data is good.
So ... long story.
Cheers!
Mark.
Tuned one using $59 years ago. Supercharged 350 TPI in a former 4.3 powered Typhoon. $59 code requires a minor re-pin to run in a 7730 by swapping the TPS and MAP inputs from memory.
I dont believe i swapped any pins on my 59$ code on the 730 ecm but its been a decade since i left that lol
look up boosted $8D code!!! I think created by member here Vanilla Ice! You can be first to really use it
what you did will work but i think his boosted code will allow more range in the ve table.
but $59 works well too, if you need files i can send my stock 305 turbo file
awesome setup, a 305 reallly comes alive on 7-8 psi
I'm still chasing some gremlins - mostly mechanical. Being a project I bought ... didn't know the history. A good example was the worn out motor mounts! Easy enough to change, but not Turbo tuning work!
Sure I like to see your Turbo file. Curious what it looks like. I did investigate $59, but not much writeup on it. So I set off on the 2X injector, Half VE approach. For a stockish engine ... it makes an OK driver. And YES 7 PSI on a 305 TPI wakes it up!
I installed real air temp sensor after the Turbo and connected it to the Oil Temp input. This is plastic type temp sensor, not the brass MAT one. Much quicker response. So under boost, the air tems went from 20 C (about 70F) to 68C (154F). Thats super hot. And outside temps were 10 C (50F) here. So on a hot summer day, this "hair dryer" is going to be hot! An Intercooler will be on the upgrade list ... even a smaller one from a donor.
Also noticed the crankcase pressure is an issue with boost. Hook that up wrong and you got oil coming out. I've got it vented now with a one way valve ... but need to add in some sort of Vac pump to keep things clean. Have a few ideas to use with a catch can. Would like to have it control from the ECM to operate near and at boost. But don't think I can use any stock code for that. Have to ponder that.
The best part of this build ... "So you got an LS engine in that? ,,,, Nope!"
Aug 2021 Update. Been lots of work this summer. Spent many hours on the code and the tuning (Thanks to S_AUJP Turbo Edition!). In it's current state, I am running a peak boost of 10 PSI (5000 RPM range). I've added an intercooler from the original setup which was a blessing. I also swapped valve springs out for some stiffer ones ... I need to redo valve seals, so easy to swap springs then. It runs and drives like a stock setup, no indication of anything unusual. Once you get into it, then boost comes on and you are on your way.
I was running 6 PSI for the longest while. Good for basic tuning. Didn't see much for spark knock. Worked well with the non-intercooler setup. Then added an intercooler and I increased boost and worked on the tuning. 94 octane gas works ok, but I found adding octane booster removes any knock and boost works well up to 10 PSI. AFR is decent. No knock. The issue I will see soon is the injectors sizing. I'm using 38 lb (2X stock). PW is over 10ms at 5000. So not much room to move from there. But really ... this is all the boost I want to push through this motor. See if I can find a race engine with good internals which would tolerate 20 psi. :-).
The project has been a great learning task on tuning, and making the turbo work. Some things learned so far:
- Using an old car for a new project ... check all the usual wear items! I had to swap motor mounts, Trans Mounts, Lower control arms. There were all done. I ended up boxing in the lower control arms in the rear ... just because I was bored. In the end, new rad, new hoses, new mounts and bushings, new brakes, new u joints, and so on. 30 years old ... check em.
- An intercooler also works well to BLOCK air getting to your rad! Needed to redesign my cooling fans .... Flexolite 420 twin setup fit in the tight spaces. Works ok. Fans are set to come on FAN 1 at 175 and Fan 2 at 185. Thermostat is 160.
- Oh ya, when you set Thermostat at 160 ... make sure to adjust all your Temp settings so that it doesn't think you are still warming up the engine. Some early learning on AFR in boost ... needed to find all the sources that impacted it.
- VE and Turbo. Curious, the TPI long runner still shows the same torque and VE efficiency in boost. The VE table shows some fall off in the higher RPM as it would in NA.
- Spark - While you can reduce it in boost a little with each PSI of boost, there is more to it than that. Rowing gears under WOT in one pattern, and starting from 3rd gear in low RPM is a different pattern. So lots of testing. And octane is your friend for testing! I have more work to do in the spark table. Even some testing to see if I can spool up the turbo sooner.
- Wastegate doesn't work like you think. You'd think a 6 PSI spring will only open at 6 PSI of pressure. Nope. There are other things impacted that. Having an electronic boost controller would make things more precise, otherwise you need to do some testing to get what you want.
- Blow off Valve. Whooooooosh. Sounds cool. I did a measurement with and without the BOV. Without, you can see a serious pressure wave go back when the throttle is closed at higher RPM. I can't recall the exact numbers, but it was 2X or higher. BOV is your friend. And you can use one that doesn't go Whooooosh.
- Keeping the battery up front took some work. Tight corners with intercooler pipes. I'm sure I've lost some flow, but I didn't want the battery in back.
- Flowmaster Chambered Mufflers don't help a Turbo. No waves left to cancel out. I went with a straight through muffler instead. I like the sound better. No louder whatso ever.
- 3.45 gears ... I'd bet the car would be faster with 3.27 or 3.08. Let the boost work. In first gear, it's tough to build much for boost. I see the higher boost in 3rd.
I'm sure some will mock me for using a 5.0L ... but really adding a Turbo is the best thing you can do for it. Doing the text book math ... if my 1990 305 speed was 225 HP stock, adding 10PSI is like 68% more power, or 150 HP. I will most likely set the boost DOWN to 6 or 7 so I can keep on pump gas. Maybe add in a dual boost controller so I can swap to higher boost if I can going to the track.
Yes the TRACK. I have not made it there yet. On the list.
I still have work to do. It's been fun. Many thanks to Elky for the Turbo code. My hacked MAP version got it running but gave up lots of driveability. Now I have both worlds.
Tech Specs:
- S_AUJP V7 code
- GM 2 bar MAP sensor (early 90's edition)
- CXRacing Turbo
- Aftermarket Intercooler (similar to CX racing version)
- Upgraded valve springs over stock.
- TPI Airfoil ... figure pushing air into the TB needs a better transition.
- 1990 305 TPI, 5 speed, 3.45 rear.
225hp was what the brochures said back in the day. My point is the increase with 10psi. so base it off what you want i suppose. Unsure where your 140 number comes from. never seen it published.
To be factual ... 1990 specs ... guess it was 230 for that year.
The long block is the same, the exhaust manifolds and single cat vs dual cats makes the HP difference. Single cat engines had smaller exhaust manifold openings and a smaller Y-pipe from a TBI engine. With headers and exhaust they are in the 240-250 hp range. I had a flat top piston 305 with 081 heads and a stock 350 TBI flat tappet cam. With a stock TBI manifold, TBI, headers and decent exhaust it made 190 rwhp and 268 rwtq through a 700r4, 2-piece driveshaft with carrier bearing and 8.5 rear while spinning a 7 bladed mechanical engine fan.
My stock 305 LB9went 110 mph in the 1/4 On just 9 psi with a lazy leave and slow boost ramp due to rear mount turbo. I def had valve float and or ignition issues up until that point. Think distributor cap was cracked as it shocked me one day lol i tried msd ignition box and super tight plug gap to get it to go 110 mph. I was gonna change the cap but started seeing coolant pushthru heater core in boost so i took turbo off and sold the car which was a huge mistake
My stock 305 LB9went 110 mph in the 1/4 On just 9 psi with a lazy leave and slow boost ramp due to rear mount turbo. I def had valve float and or ignition issues up until that point. Think distributor cap was cracked as it shocked me one day lol i tried msd ignition box and super tight plug gap to get it to go 110 mph. I was gonna change the cap but started seeing coolant pushthru heater core in boost so i took turbo off and sold the car which was a huge mistake
that car should go very quickly in good condition
I upgraded my valve springs already ... figured added boost works against the spring pressure. 110MPH? That' is low 13's or high 12s?
Yes I am concerned with too much boost and head gaskets. So I will most likely test it at 10, but drop back to 6 for normal use.
Yeah it ran 13.40 like clockwork. Same time on 8-9 psi as 15-20 lol. Just didnt light off the higher boost
if it had drag tires and a converter i could likely have left on a psi or two and def cut 60 foot down from 2.0 to atleast 1.8 on motor and likely 1.7’s in boost plus spooled so much faster in the first 100 ft. Def would have been 12’s. My bolt on ls1 trans am cut 1.6-1.7 60’s and ran 12.50’s at 108
Yeah it ran 13.40 like clockwork. Same time on 8-9 psi as 15-20 lol. Just didnt light off the higher boost
if it had drag tires and a converter i could likely have left on a psi or two and def cut 60 foot down from 2.0 to atleast 1.8 on motor and likely 1.7’s in boost plus spooled so much faster in the first 100 ft. Def would have been 12’s. My bolt on ls1 trans am cut 1.6-1.7 60’s and ran 12.50’s at 108
Very nice. I figured anything in the 13's would be decent ... for a 305. :-)
Quick update. I was at the local drag strip on Friday. Nice weather .. .maybe 72-74F outside. My car ran it's best of 13.78 @ 104MPH ... and it did that with huge clutch slippage in 4th and 5th. As soon as I got to 4000 RPM, the boost was 10 PSI and the clutch just spun. So ... 13.7 was decent given my clutch needs to be replaced. (I am at 2200ft elevation ... so consider than when you look at the time).
When driving the car ... it is pretty slow out of the hole. Folks walked passed me. Not much boost building in first, a little more in second, and 3,4,5 I am at full boost (with my wastegate). So really slow off the line, but it runs fast top track. I don't even think I need sticky tires ... probably could run it with stock 245's.
So ... going to swap the clutch as next step. The tune (S_AUJP) works well. Wideband monitoring works. I need to add some fuel as I enter boost as the transition from NA to boost is an odd step. Need some thought into the transition and where to add fuel. Also ... drag strip isn't like street use. Almost 2 different tunes.
Overall the project is successful. Stock ECM and turbo. Very impressed.
05-08-2021, 11:09 AM
