Question's on RA XP Double Pumper



i just received this bad boy last night.

My friend and I installed it. I had a few questions. First, why does Red grind off the numbers on the side of the pumps ? I am not sure why and it got me curious. The pumps looked like one of the Holley fuel pumps I had in the car....

Also, how much horespower can the pumps support. I have the stock fuel lines and 55# injectors....

Last question is, how do i know the second pump is working? The kit didn't come with a light. My friend said to just run the car like i normally do..But around 10# of boost, my car should run really rich and start to feel sluggish. Is this accurate ?

Thank you for the answers. There is alot of good knowledge on this board !!!!!!!
The numbers are ground off so you don't know what pump he's using.

The double XP and 55's should be good for low 10's (maybe better) I KNOW a single Walbro 340 will go 125mph.

I like to run a adjust able hobbs switch. I think 10psi is too early. You really don't need that much boost there. You can run a LED into the car to let you know when the pump is on.
I have the ATR setup that comes as a drop in with second pump indicator on light. Better kit IMO. I have the second pump set at 17 PSI which still may be a little low with 55's. I guess you could always tap the wires and run your own second pump on indicator. Does it come with a Hobbs? If so, crank it up because 10 PSI is way low.
Do ya'll know if Red's kit has an adjustable Hobb switch? I didn't take a look at it...

If not, how much does one cost? So ya'll are saying, why have the pump activate at a measly 10#...The one pump and injectors can handle it...Then around the 17# range, I can set the second...Will this make tuning the Fuel pressure easier?

How do u tune the FP? Cuz now i will be really rich on the bottom end.....I am getting confused
the double pumper will not affect your fuel pressure if your regulator is working correctly and you should not go "rich" just because the 2nd pump kicks in......the regulator controls the fuel pressure, not the pumps.....all the second pump does is insure you have enough volume to meet the demands of your fuel the required flow at some pressure....the pumps just pump the same all the time(the second pump just adds volume capacity)
Most cars I've did the double gained about 3-4lb fuel pressure. Remeber that its "volume" that is being increased more than "pressure".

Most good pumps ran go well over 20psi without a problem. I would set it to come on around 20psi or just over, that is just MY opinion though.
Yeah the turn on of the 2nd pump can be seamless if the turn on point is high enough. But if it comes on too early the combined output will overwhelm the return system amd the pressure will rise out of control. On mine I found 20-22 psi boost was a good turn on point. The car ran over 130 mph through the stock lines and filter with no signs of of fuel delivery problems (yes I was looking for them too ;-) Looking to the future though, :) I recently upgraded the feed line to a -8AN and put in a K&N stainless screen filter.

Check the pressure switch supplied (or just call RA) for a little rubber plug that covers an adjustement screw. If it's there you're in business; if not you can get an adj pressure switch.

Hope that helps.

The ones from Red that I have seen aren't adjustable.

I have an adjustable Hobbes switch and set it to turn on at 19-20# of boost. Any earlier and the car goes rich as stated and slows down a bit.
Well, I took a look. Ya'll are correct. The switch is not adjustable. SO I guess i need to see what an adj switch costs.

Also, am i wrong in thinking that the extra fule pump would alleviate detonation using pump 93 octane gas???

I still have the stock turbo but we are going to replace it this weekend... But just to test the car with the duel pumps, we took the car out lastnight. It pulled very strong with 16pounds of boost. I have a CAS V2, 55#inj, THDP, ATR Single Shot..... We ran it twice...The third time, I heard pinging and we let off. Car was doing about 15pounds of boost in third gear but the pinging started in the middle of second... I would have thought the second pump would have helped to reduce ping..Am I wrong ?
Sounds like you don't have a scan tool. Do not leave home without one! The amount of fuel is just one part of the answer but almost more important is having enough octane!
I agree. A scantool is a must. If your waiting to "hear" the ping at high boost, your gonna pop. Fuel pressure can only overcome a certain amount of knock. There are still many other factors such as boost, intake temp, exhaust temp, octane, timing, etc.
yeah, ya'll are right. I DO have direct scan but the car had been tuned optimally for the setup I had. So I hadn't put the laptop in the car for awhile.....I guess, one thing I have learned with these amazing cars is that it is ALL about the TUNING !!!

One side note, though, do ya'll think low 11's or maybe high 10's are possible with street gas? I am curious because all my buddies seem to have LT1's with NOS and they are cutting 1/8th mile times in the 7.20 range. I would like to be able to compete with that...

Anyhow, I appreciate all of ya'lls input....This weekend, we are scrapping the stock turbo, and installing the Turbonetics T70 4 bolt with an ATR downpipe, and a beautiful, GORGEOUS TIAL wastegate.....I'll keep you all posted....

Thanks !
Originally posted by Qwik6

My friend and I installed it. I had a few questions. First, why does Red grind off the numbers on the side of the pumps ? I am not sure why and it got me curious. The pumps looked like one of the Holley fuel pumps I had in the car....

>>> I was told by a Buick vendor awhile back that reds xp plus pumps were made especially for him and no one else. So I wonder if the same is true for his double pumper. I would assume so.

Also, how much horespower can the pumps support. I have the stock fuel lines and 55# injectors....

>>> I remember a hot topic about a year and a half ago on the big list about this, scratching my head here to remember but I believe it was stated that the double pumper and stock fuel lines were good for between 900-1,000 HP. Although IMHO I think that would be stretching it a bit not to mention a bit risky but I'm sure others have run it and run it quite well.

I ran reds double pumper in 98 and did not have any luck with it, in fact lost a motor over it.

Best of luck with your new combo and keep us posted.

I've never had a rich problem from the second pump kicking on at 10 psi with my RA XP+ double pumper.
This is a post (edited) from another thread about trying to go 130 MPH trap speeds. Thought it might be helpful as to what they can do.

How much is enough?
For you doubters in the crowd that feel that the double pumper is just not enough. I called Terry to verify how fast his car had gone on the Red Armstrong double XP and stock lines and he believes it went 9.2's at nearly 150. When I told him why I was checking he told me to ask Dan White how fast they had gone. For you unbelievers Dan White is still using Red's double XP's a stock tank with on his Stage II twin turbo car feeding 166 lb injectors. I did not ask what he was using for fuel lines but I don't think that matters much unless you are trying to go faster than 9.2's as Terry did. So far Dan's car has gone the best of 8.30 @ 170 MPH. If you have seen Dan's car you will know it is not an ultra light tube car to the contrary he is going that fast on a 28x10.5 tires (NO NOT a W).

Sorry for all the rambling but hate to see a great setup not get completely accurate representation. Red's pumps work period, and they are enough. Any part can fail or be affected by external circumstances, like contaminated fuel. Been there done that lost a pump and a motor. Now you know how I really feel. Have at it use the Twin XP's go fast. Dave