Hey guys,
I currently have an on3 7875 which I used briefly on my stock block 347. Before that block split into many pieces I built a dart block 363 which I now have up and running. I am wanting to make about 800ish at the wheels with around 15 lbs and right now I am not seeing that 7875 cutting it. Compressor housing is too small, AR is .96 and the turbine is 75mm so I am forecasting lots of back-pressure.
I am looking at the VS Racing 80mm billet unit with the 83mm turbine and 1.25 A/R hotside but I see that they also have a 1.10 A/R version as well. (both are t4 frame)

This is a street car that I want to spool pretty quick (the 7875 makes boost at part throttle and is at full boost pretty well instantly) so I am a little concerned with the 1.25 AR.
The rest of the setup is:
363" sbf
Megasquirt MS3pro full sequential fuel and spark
10 to 1 compression
AFR 195 heads
Comp hyd roller 220/220 .570 lift 113 lsa
non-intercooled
Devils own meth injection controlled by the MS3pro ( dual d12 1000cc nozzles)
Powerglide with a billet 3700 converter and pro tree brake
373 gears/26" ET streets

Street driven fun car.
Advice??

 

Single T4's just don't belong on a V8 IMO. The 1.32 T6 will spool just fine on a healthy 363 and provide much less back pressure.

 

I would live to have a t6 frame but unfortunately there just isn't the room. This is a 69 Mustang with the turbo on the pass side where the stock battery would be. My 7875 compressor housing almost touches the radiator as it is. I am not too concerned about t4 limitations as this really is a street car and I am running very low boost.

 

The s400 chassis turbos (even the T4) are huge. If it’s close with the 78/75 now, I doubt you’ll get an S400 in there. That said the 1.25 T4 S476-s480’s with the big 87/96 wheel stuffed in the t4 housings would do what you are asking.


I’ve run both, and if U can fit the T4 S400 you ‘ll likely be able to fit the T6. I did cut the goofy exhaust flange off and weld a 4” vband to my T6. For space reasons.


Good luck!

1.25 T4 VS 1.32 T6 comparison.

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Depends how much you want to spend. Below is a picture of a PT8285 next to a PT7675 which is roughly the same size as your 7875. It is pricey though. Spools quick on a 347 though not as quick as the PT7675.

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So what do you think? Have any chance of it fitting???

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I doubt it. Maybe with a big enough hammer and a sawzall! Might have to move the alt. too. Or get a smaller one.

 

Yeah. I had a gt45 in there at first with a 1.15 A/R hotside. It was tight but fit. The compressor discharge hit the radiator so I cut it shorter and modified the outlet direction. Problem was it didn't make good boost till over 5500 rpm. This 7875 makes boost by 3500. I just haven't cranked it up to see if it will maintain yet.

 

Is it the billet 78/75? It might surprise you… I’d give it a shot.


I believe the VS racing 88/83 has a smaller footprint than the S400 stuff. Might look into it. I believe they are similar to a GT45 size wise. They have a 78/83 as well if you ask. The exh wheel size is what will limit the 78/75.


Might ask Viren which he would suggest. Smaller you keep the compressor relative to the exh wheel the quicker it will spool. So if the 78/83 would do it, I’d go that route over the 88.


http://www.vsracing.net/catalog/product_info.php?cPath=21&products_id=1354

 

The Magnum Performance Turbos MXM588/85B-CORE (1.44 A/R-Vband in/out turbine housing) would be a great solution to this problem. This comes with industry's first billet compressor housing as well as billet wheel. See below and godspeed!!

https://mpturbos.com/m58885--turbo.html
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The guy is looking at budget sub $1000 turbos. And rightfully so IMO. I can't see a stock block build needing a $3000 turbo! Yikes...

 

We have those too... https://mpturbos.com/m48078--turbo.html journal billet turbo for sub $1000.00 see below. Furthermore, a T5 inlet and 4" vband outlet fits right in between that t4/t6 option. 1 year warranty includes racing...

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http://www.jegs.com/i/Magnum-Performance-Turbos/659/607778J115BW/10002/-1

 

You may have to move some stuff. My car is room limited around the turbo so I stayed with a T4 turbo. We also have local class limits. I had Jose at Forced Inductions put something together. I'm sub-5's and well over 140 in a 3200 pound car in the 1/8th with a 363 and not optimized yet. My turbo is located almost where yours is but I cleared that area. Do you have any pictures better showing your mounting area?

Even a PT 7675CEA with a small DP ran 5.30's in the mid to high 130's at 3200 lbs, so you can make good power with a small turbo.

The way I worked mine was to measure all clearance limits out to where I could not easily move things, make a drawing, and search out a turbo that fit the area. I'm pretty happy with the T4 from Jose, but once I get the chassis fully under control I'll probably look for more power.

 

Here's what our MXM477/78JB made at 18psi on pump gas and this is with fuel problems on a stock c7 at 8000 ft altitude in Colorado... 76mm compressor once again $1000 gt42 style frame. Contact Nick at PTSFAB in Boulder Colorado for any details.

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Tom here are some other pics. Some are with a gt45 with a 1.15 A/R hotside and others with the 7875.
The gt45 was substantially larger. Gt45 touched the radiator while the 7875 has 1.5" clearance.

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434josh - is that the CX Racing 64-68 hotside? How do you like it?

 

I do like it however I would assume on a 65/66 and 67/68 adjustable motor mounts would be needed. Pass side touches my tower and it's a 69.

 

I ordered the Ron Morris adjustable mounts, I figure between that and a little heat and hammer I can make it fit. We’ll see I guess. Didn’t mean to hijack your thread, just saw the hotside and it looks familiar. I haven’t installed mine yet.

 

Are the mounts able to adjust up or just down? If just down they WILL hit the pass side header and can't be made to work. You need to raise the motor up about a half inch and possibly slide over to the driver's side a quarter inch.