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.
hey guys. I recently acquired a g45-1500 knock off turbo its a ball bearing 76/89. compressor is 76 inducer 109 exducer, turbine is a 89x82. Its t4 1.15 ar.
so my questions are A.) will this be good on my set up for a street car that occasionally sees the track. and B.) how would the spool be at higher elevation (Colorado)
Little info on my set up. its a stock bore ls1 with. Mahle pistons, scat rods. has ported 241 heads. has upgraded valve train can't remember the specs. and I'm on a Elgin turbo cam (basically a sloppy stage 2 I believe). trans is a 4l80 with a circle d 3800 converter. will be sticking with my bumper exit.
I recently was on a on3 7875 cast version and decided to upgrade since vsr was having a good sale. I was going to run a next gen 7875 but decided just to go with this since the sale price was so good. any input is greatly appreciated. At the time of purchase I was told it would be great but after sizing it up to my old 7875 I'm having some 2nd thoughts. I don't have any goals for power in mind. The car ran 11.0 at 133 at the local track on 11 psi. I probably should have just raised my boost level but it was falling off a little on the top end.
I think it will work very well, the larger 89mm exhaust wheel will provide more rpm than the 75mm wheel.
It may spool slower than the 7875 but you probably won't even notice if the tune is correct.
How will it spool at high altitude?
I can't answer that, but I think it's a small enough unit that it shouldn't be a problem.
that's what I'm hoping for, I know I was just tickling the 7875 ability, however I bought the car as it is so was itching to change something on it. Its sitting at my buddies fab shop waiting for the downpipes and cold side piping but I'm getting antsy!
I ran an old Turbonetics T7875 on my last car and while it made 700whp through the six speed, it was pretty much done by 6,000rpm so I think that bigger turbine will help with that.
You can reasonably get away with 14 lbs. on pump gas only but be very careful going past that.
yeah I only rev to 6400 ish. I think 14 psi would be plenty for me if its anything like the 7875 was. I do run E85 on this car. actually hoping to order a s60 rear end soon as well so I can actually play with some power.
yeah I expect it to be little lazier then the 7875 I had. hoping it isn't something that takes the street fun out of it however. I am from the turbo 4cyl world where slightly larger turbo means lag for days so was just making sure it wouldn't be a spool at 5k sort of deal. I forgot to mention it is a billet wheel, not sure if that has any change on spool abilities these days
It should be decent, I think 100-150hp over the g42 stuff and those are better than the standard 7875 IMHO. The high blade count compressor will help spool and the g turbine is about is good as it gets right now. Let us know how it goes I think you will will be surprised.
yeah I only rev to 6400 ish. I think 14 psi would be plenty for me if its anything like the 7875 was. I do run E85 on this car. actually hoping to order a s60 rear end soon as well so I can actually play with some power.
If you're running E85, then you can run well above 14 lbs. so don't think that's the limit.
Also, don't be afraid to go above 6,400rpm, I shift my forged rod/piston LS1 at 7,000 rpm and it loves it.
I'm running 14lbs. on pump swill and seriously considering swapping to E85 and putting a barrel in my garage so I can turn it up more lol.
Hell yeah, I might up the rpm alittle and see how it does, my 4l80 has given me a few hiccups so I beefed it up little recently, 300m input shaft 300m main shaft and then a billet forward hub. also has some decent clutches and Steeles. it started making some drag noise after I broke a drive shaft so I won't lie I've been scared to cause it more damage but I'm kinda to the point of just letting it do its thing.
ill forsake update the thread once I get it all buttoned up and tuned to show my outcome of the turbski.
Why do you say its a GT45? Those aren't anywhere near the common gt45 wheel measurements. Did you verify the wheel diameters yourself, or were you told thats what they were? Sounds great if those are the actual numbers... just don't want ya to stab a typical china GT45 turbo on there and be disappointed.
is it this unit? Note is says nothing about a gt45 in the AD.
just updating the thread, I finally got to drive the car with the new turbo set up. It spools faster sounds better and carry boost to the top of rpm with 0 hesitation. I'm still on the old tune so have to baby it into boost but so far I'm really digging the upgrade.
So what do you think of the ball bearing set up? Are you water cooling it? Is there a built in oil restrictor?
I have some reservations on the ball bearing center sections, they are more expensive and maybe more fragile? But these knockoff G42s and G45s seem to be all ball bearing. Except the one I posted in my other thread is journal bearing. Weird.
So far so good I’m only 50 miles in on the new build. Turbo seems to keep spinning for 1.5 mins or so after shut down. It sounds alittle quieter then the on3 but i hear it’ll get louder as it breaks in.
it spools better carries rpm better ect. I’ve only eased into it twice since I’m on a new rear end as well.
02-22-2024, 12:29 PM
vs racing g45 (76/89) too big for my set up 
