CTD2500
Brown Between the Cheeks
- Joined
- Aug 3, 2013
- Messages
- 477
Would like to see your charge air cooler between stages. Any pics? I'm assuming its air to air...
70 psi boost with 60 drive that's very good regardless of how hard the primaries are pushing! You would likely have more pressure between stages without charge air cooling (assuming that its both cooling the charge and not restricting flow). Would be nice to see the turbine speed on the manifold turbo. Actually you might benefit from losing the cooler between stages if it raised the between stage pressure by only 5 psi lets say. 18 psi doesn't make too much heat. 70 psi is plenty though for your truck,no need for more.
I finally broke down and bought the garrett turbo speed gauge for the manifold turbo on my TDI car. My wastegated s362 Villian is currently set to run 90-100k rpm. At 4500rpm under full load the Intake manifold pressure was 125 psi and drive pressure was 55 psi with 45 psi boost between stages (s475/87mm with air to air between stages) .
I’ll have to take some new pictures of the interstage cooler and how it’s routed. Pics I had back when I built it are on old devices.
I think it was 2015 that I added the interstage cooler, and I was able to set it up so I could quickly reinstall the non-interstage pipe and drive it back to back to compare. I don’t recall seeing much difference in interstage boost (I think I was running a GT42 for a primary at the time), but I remember full power being smokier and maybe a little weaker without interstage cooling, but the trade off was that having the secondary draw through all that piping, an intercooler plus the primary turbo made spoolup off the line noticeably worse.
To fix that, (mostly) I added a check valve with another air filter just before the secondary compressor inlet so it could draw air easier, then the check valve closes when primary boost begins. This many years later it still works seamlessly; you wouldn’t even know the check valve is there.
The last primary I was running was an S372 sxe with a 1.0 housing. Primary boost was in the high twenties at full throttle. These two 57mm units should outflow that by a decent amount (65 lb/min each for 130 combined) so I expected at least the same boost from them. When it was that low, I wondered if the turbines I’d picked for them were too big and not allowing proper drive pressure to build, but when I hooked up the gauge to the hotpipe and saw 30 psi drive pressure it made me wonder about an intake leak. I ran a 57 sxe like these on the manifold before this setup and at 30 psi it was 1:1 drive/boost. Granted I don’t know how much the primary pressures affected that, but it seems to me that for 30 drive, boost should be higher—assuming running two in parallel act the same as a single. This is kind of uncharted territory for me, lol.
I suppose it’s possible that the cooler might be small for this much air? It’s the most primary I’ve ever ran by a big margin. The interstage cooler is a Treadstone TR1235, which is 12.5” tall, 3.5” thick with a 22” long core, if I remember right. 1142 CFM, according to the website. I’ll admit, I’m not an expert at sizing coolers, I just bought the biggest one I could fit in the space I have. I guess I could try reading primary boost before the cooler if I don’t find any leaks.
Am I reading your post right? Are you running a 62/75 setup on a TDI???