S475 surging issues!

B

bmf racing

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Oct 6, 2013
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I'm having issues keeping my double batmowheel s475 from surging down the track. It's an 87 1.0 brand new from stainless diesel. Stainless diesel t4 manifold and a sdp external gate. I use to be on this fourm a while back as B.M.F Racing I had the silver sclb vp truck that went 10.9s.

I bought Pete 4121s old p pumped 24v that's what the turbos on.

I'm going to fill out my sig so you guys can see the details. Thanks for any help!
 
I have external gate set right at 50lbs even bumped it up to 60lbs still same issue. Turbo will not light unless I use my purge selonoid and keep bumping it while staging. Will stay on top if my converter stays unlocked. But that equals slow times ��
 
What size gate? I'm wondering if the gate is cracking too far to regulate boost and you're fighting it.
 
What rpm are you shifting at?

I have a very similar setup to what pete had and just swapped to the same 75/87/1.0 charger. Mine will get under the charger easy if i dont shift high enough, but it has never surged on me otherwise.
 
MIne would do the same thing if I didn't keep the rpms up and shift above 3500rpms. But as soon as it would shift to OD it would surge. so I stayed in 3rd till about 4k rpms
 
12VALVEADAM said:
MIne would do the same thing if I didn't keep the rpms up and shift above 3500rpms. But as soon as it would shift to OD it would surge. so I stayed in 3rd till about 4k rpms
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I have a set of haisly 5ks I'm thinking about putting in. Shifts are around the same as yours. Od does come on a tad early. The thing that makes my truck feel so slow is that I can't lock it up and with a 2400 stall trans temps get hot quick. Egts are also very high.
 
shortbusdriver said:
How is the wastegate regulated?
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It has dual springs inside and with that alone it would open at 50lbs. I just Plummed a boost valve into my intake to the top of gate. Did 2 full turns out and that adds 10lbs. I will take some pictures of the setup later today
 
I had 5ks in mine also but my temps never went above 190 on back to back runs. I also locked in 2nd
 
Not sure on size of the springs in that gate but take the small one out, only run one. Run a cheap air regulator with boost to the top of the wastegate (which might be what you are doing). When running two springs they seem to want to open and close causing a surge.
 
More boost will make the surging worse....try backing it off to 40psi and adding more spray....
 
shortbusdriver said:
Not sure on size of the springs in that gate but take the small one out, only run one. Run a cheap air regulator with boost to the top of the wastegate (which might be what you are doing). When running two springs they seem to want to open and close causing a surge.
Click to expand...

Yes it has two springs. I will take the small one out. What your saying makes sense. I have an air regulator going from intake elbow routed to top of external gate.
 
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