P-Pump 24v Idle Surge

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Yotadzl

New member
I've seen a little about this on here, but no real clear answers on how to solve this. I am working on a 99 24v with a p-pump swap. The components I am aware of (I only did part of the build) are as follows:
-180 pump with 7mm dv, 4k springs, hamilton v2 pump cam and springs
-DDP custom injectors (I don't recall exact flow specs, but around 52-56 lph I believe)
-Industrial Race twins (older with 66 Silver and 87 mm S4T)
-Built trans with Stock stall, maybe 2200 rpm?
-FASS 260 with TorkTek orifice overflow

The problem is it surges a little in neutral, but when dropped in gear it surges really badly. I've built similar pumps for 12 valves that did not have this issue. I've heard it may be injector related, but not exactly which way a person would go to help alleviate the issue. I have tried different idle springs and idle rpm settings to no avail. I also swapped from 191 to 7mm dv, which did not help the surge.

So has anyone been able to solve this issue? And be willing to share what they determined? I know some surging is normal with tight governor springs and built trans, but this is extreme.
 
What is it timed At? I'd try playing with the timing a little. The One and only p24v I've been around needed alot of timing to run right.
 
I have not seen a v2 cam idle smooth yet. Imo it needs more timing but I do not see that helping your current situation. May want to verify pop pressure.
 
When I was playing with the p-pumped 24, I discovered how injector sensitive they were. Once I figured that out I found a place to get them made and stopped fighting it.
 
jlbayes said:
I have not seen a v2 cam idle smooth yet. Imo it needs more timing but I do not see that helping your current situation. May want to verify pop pressure.
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I tried to keep timing conservative on this build because the customer thinks he wants to tow with it and was also having issues spooling the turbos
 
Yotadzl said:
I tried to keep timing conservative on this build because the customer thinks he wants to tow with it and was also having issues spooling the turbos
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I have a similar turbo setup but with smaller turbine in the secondary. I would not ever dream of trying to tow with it.
 
jlbayes said:
I have a similar turbo setup but with smaller turbine in the secondary. I would not ever dream of trying to tow with it.
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66 spools poorly, even with lots of fuel. Are you running 12V injector springs and pop off pressures on your injectors?
 
RonA said:
66 spools poorly, even with lots of fuel. Are you running 12V injector springs and pop off pressures on your injectors?
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Not with a 68mm turbine. They are whatever Weston build for the application. They seemed to make good power even with a 12mm pump. Good enough to hurt the engine.
 
I believe they are 12 valve springs in the injectors.. They were built for a p pump application
 
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Yotadzl said:
I believe they are 12 valve springs in the injectors.. They were built for a p pump application
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Too bad you don't have access to a set of M6's or M7's. Set to pop at 290 it would be interesting to see if it helped the idle. I don't know if Exergy is still around to balance injectors. It's been a while.
 
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