When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I’m getting ready to log back pressure with my new 70/70 turbo. I’m going with the low dollar motorsports $50 100psi transducer which is recommended over the generic $20-35 100psi transducer beloved to have more accurate reading with less noise. Then got a $12 copper tubing mechanical gauge install kit. That’s all you need. I got a 15ft harness and I’m gona pull the oil pressure and connect in on my Holley term x and I will be able to log back pressure with a run and also see how it correlates with boost etc. I could set it up as a input but not worth it as it’s just for testing and then will remove. I’m also gona run boost, pre turbo back pressure and after turbo to see how much I’m seeing in the down pipe and how that relates to the pre turbo pressure. Less than $100 but that’s with the term x ECM. My HP tuners I got the logging external connector where I can add external inputs and it worked for a WB02 I ran when I used HP tuners.
I dont see any noise or inaccuracy with the cheap sensors in Holley, I removed the $150 Holley 100psi sensor and installed the $20 Amazon 100psi sensor the logs are identical.
I've actually seen more failures on Holley sensors, over the cheap Amazon, and really no difference in data values back to back. It hurts way less when a $20 sensors ***** the bed.
I picked up one of those 100 psi stainless sensors. It looks to have a linear output 0.5v - 4.5v.
I have the HP Tuners MPVI Pro so I should be able to have the signal go into one of the inputs. What's the best way to set up the scanner? Anyone have the logic to set up a user defined sensor?
I know I'll have to provide a 5vdc source to power the sensor as well.
Interesting convo. Buddy and me been thinking to plumb in something in our cars, where is the best place to place it?
Mine’s in one scroll of the turbine housing. Coiled tubing to the sensor as mentioned above. You can see it behind the turbo mount in front of the head.
I just pulled my billet gen 1 78/75 and put in the VS next gen billet 70/70. Also welded a bung in the merge t4 for the back pressure setup. I installed but out Teflon on the 1/8 npt threads on the hotside and the sensor. Will the PTFe tape be ok with the exhaust temps? What do you guys use to seal the connection on the hotside?
think I’m gona run it using the oil pressure sensor connection so I don’t need to wire and configure another input on my term X. Get my reading and pull it as I just want to know my ratio on the street.
Im "a poor" as all the douche bags say, but i uses this and adapted it to a compression tester and drove the wheels off of it and checked what it registered.
Question about my BP results. I’m seeing 2-2.3:1 on my cammed 5.3 with a 70/70 .96 VS billet turbo. Same BP from 10psi to 17psi and 6k rpm. Seemed high for my boost and I reached out to Viren and he said it should be much lower than that on my application. Like 1:1 up to about 15psi.
trying to think of why it’s so high and I can’t find the thread now but it said something like it to put the sensor bung in an area of forced pressure or something as it will get a false higher pressure. Mine is on the outside of radius of flow into the turbo for packaging and if I was looking at exhaust flow as a liquid it would be cramming into the sensor port under flow and pressure giving me a false reading? What do you guys think? I believe I should have installed on the flat edge top of bottom. I could pull the turbo and weld a bung on the bottom side just for ***** and giggles.
min also not running that mushroom filter but a 90 degree into a K&N filter.
Yeah I was curious how he got any downpipe in that setup. I thought my setup was tight, but I guess I have a downpipe on mine, like in the mix so it is different.
Sounds like someone is getting smoke blown up their ***. No way in hell a cammed 5.3 gets a 1/1 bp ratio with a 70mm anything. Maybe that turbo gets that on a honda civic? If this post was about a 3.0 2jz, I might think they were just exaggerating, but claiming 1/1 is normal in this case is bullshit. That being said, if I saw 2.3/1, I would make sure I had no leaks on the hot or cold side. Anything small enough to give 2.3 backpressure should give super insta spool.
The way the other bank Ts into the hotside looks restrictive, but I agree I can't see you having 1:1 backpressure anywhere above 1500 rpm with a 70mm. Do you have a flex joint in the hotside? If so have you checked the inside of it lately?
The way the other bank Ts into the hotside looks restrictive, but I agree I can't see you having 1:1 backpressure anywhere above 1500 rpm with a 70mm. Do you have a flex joint in the hotside? If so have you checked the inside of it lately?
yes, I have a 2 1/4” vibrant flex bellow with solid liner on the crossover. So nothing to expand and cause a blockage.
the merge from the crossover isn’t too bad, it’s angled in towards the turbo so it goes with the flow from the pass side header. Even the WG is in direct flow to help give it priority and I’ve had no issues getting low boost on this setup and the 60mm HKS style WG.
Sounds like someone is getting smoke blown up their ***. No way in hell a cammed 5.3 gets a 1/1 bp ratio with a 70mm anything. Maybe that turbo gets that on a honda civic? If this post was about a 3.0 2jz, I might think they were just exaggerating, but claiming 1/1 is normal in this case is bullshit. That being said, if I saw 2.3/1, I would make sure I had no leaks on the hot or cold side. Anything small enough to give 2.3 backpressure should give super insta spool.
I haven’t found much if anything leak wise. No carbon or anything and the engine is so quiet I can hear the lifters so I can’t find anything at idle leak wise. Spool is pretty good, less than a sec and I can start to build boost a 1/4 throttle which is fun.
Just wondering … do you think it would be possible to make a hybrid 70/75? Like put the billet 70 wheel on a 78/75 but swap the compressor housing? The 70/70 has been running good so I will likely leave it as I don’t have to worry about balancing the turbo but I wonder if that would be possible… I have two 78/75s on the shelf a cast gen 1 and a billet gen 1. The only thing is the 70/70 has a 80 inducer and 70 exducer, the 78/75 has a 82 inducer and 75 exducer on the exhaust side. So not really gaining much flow wise I’d feel besides the 5mm increase on the exducer size.
02-05-2022, 01:47 PM
