Engine/Transmission (1998.5 - 2002) 275's are in, are my results what they should be?

[AFoulk]

got my RV275's installed today. Really wasn't very hard at all. I managed to sneak the rear set of lines out past the loop on the back of the head, didn't have to take that off.

I gotta say, I'm a little disappointed. I don't feel near the boost in power that I thought I would. I'm not sure if I actually feel any or if I just think I do. I don't know if swapping from the HO pump to the SO pump a while back killed my power that bad that the injectors just don't make that big of a difference or what. I would have thought a 30-40hp gain would be noticeable even in something as heavy as my pickup. My bottom end power still sucks, but I think id did improve somewhat. With my old HO pump, I could hit 1100* egt and 21lbs. of boost. With the SO I could only hit 900 and 19. With the 275's my boost hasn't increased at all, but my egt's will hit 1000*. Will have to take it out tomorrow when I have day light to see if I get any kind of haze out the tailpipe. Does this all sound about right though? It does seem to run slightly smoother.

 

[Regcabguy]

got my RV275's installed today. Really wasn't very hard at all. I managed to sneak the rear set of lines out past the loop on the back of the head, didn't have to take that off.

I gotta say, I'm a little disappointed. I don't feel near the boost in power that I thought I would. I'm not sure if I actually feel any or if I just think I do. I don't know if swapping from the HO pump to the SO pump a while back killed my power that bad that the injectors just don't make that big of a difference or what. I would have thought a 30-40hp gain would be noticeable even in something as heavy as my pickup. My bottom end power still sucks, but I think id did improve somewhat. With my old HO pump, I could hit 1100* egt and 21lbs. of boost. With the SO I could only hit 900 and 19. With the 275's my boost hasn't increased at all, but my egt's will hit 1000*. Will have to take it out tomorrow when I have day light to see if I get any kind of haze out the tailpipe. Does this all sound about right though? It does seem to run slightly smoother.

I don't see a box or programmer listed in your sig. Why don't you look for a used Edge EZ or similiar box. It'll definitely wake that truck up. My old '99 with Mach 1. 6's without EZ was a smoking dog. The EZ along with an adjustable turbo elbow produced all the power I needed and lower EGT's.

 

[Wiredawg]

Yep, the injectors by themselves are a little subtle... an Edge EZ will wake 'em up. They just need to be fed a little more fuel.



Wiredawg

 

[AFoulk]

I would, but I felt like i splurged enough money on the injectors for now. Once I get my tax return, I'm gonna put a SB DD clutch and new hydraulics in it, otherwise I'd get a box next. I'm waiting for the Quad Adrenaline to be released before I buy a box. I'm sure I can get a EZ cheap on ebay, but I don't wanna waist the money on that if I'm gonna get a different box within the next year anyways. I got the 275's mainly for a boost in fuel mileage for now. I'll eventually upgrade to some Mach 4's in 2 or 3 years. I figured the 275's would pay for themselves in that time frame if they boost my mileage 1-2 mpg like some people with them stated.

 

[AFoulk]

On a side note, if I would decide to get a used EZ for now, would it have to much added timing since I have the HO engine with higher compression pistons? It already kinda "knocks" and "nails" under moderate acceleration, I don't wanna agravate the problem. I'll have to run it good tomorrow to see if the new injectors helped that at all. I didn't have a whole lotta miles on the old injectors, but the tips were carboned up pretty bad.

 

[PPettit]

I thought a major part of what made the HO motor an HO is that it already had upsized injectors. If this is the case you may not have added much at all by installing the 275's. It might be worth your while to do a few searchs and see if I am totally clueless or not.

Installing an EZ or similar box will really bring a smile to your face. It made a big difference on mine when I had it on there.

 

[timbo]

You need a boost fooler! The ECM is defueling automaticlly. If the map sensor see's 20+psi of boost it will defuel and hinder the performance drastically. You can buy just a boost fooler for around $75,but if you buy a programmer(box) of some sort, the boost fooler is built in and it will really wake it up!!!

 

[PPettit]

Unless he has modded his wastegate line It should not be able to make over 20 psi boost anyway.

 

[timbo]

Unless he has modded his wastegate line It should not be able to make over 20 psi boost anyway.

Good point! Afoulk is your waste modded? Has the previous owner tampered with it, Sometimes it's hard to tell just by looking at it. I've seen people put 1/4 bolt in the in line (to plug it) and hook it back up. If everything checks out OK in the wastegate, then your just unhappy with the injectors.

 

[PPettit]

Without a boost fooler more than 20psi should set a code for overboost along with defueling. Therefore, the CEL light should come on also.

 

[johncameron]

On a side note, if I would decide to get a used EZ for now, would it have to much added timing since I have the HO engine with higher compression pistons? It already kinda "knocks" and "nails" under moderate acceleration, I don't wanna agravate the problem. I'll have to run it good tomorrow to see if the new injectors helped that at all. I didn't have a whole lotta miles on the old injectors, but the tips were carboned up pretty bad.

Get a SMARTY and run non-timing softwares!

 

[cArNiVaLwOrKeR]

I would, but I felt like i splurged enough money on the injectors for now. Once I get my tax return, I'm gonna put a SB DD clutch and new hydraulics in it, otherwise I'd get a box next. I'm waiting for the Quad Adrenaline to be released before I buy a box. I'm sure I can get a EZ cheap on ebay, but I don't wanna waist the money on that if I'm gonna get a different box within the next year anyways. I got the 275's mainly for a boost in fuel mileage for now. I'll eventually upgrade to some Mach 4's in 2 or 3 years. I figured the 275's would pay for themselves in that time frame if they boost my mileage 1-2 mpg like some people with them stated.

I had the bigger injectors and went back down to the 275's, and will never go back up

 

[Mundgyver]

got my RV275's installed today. Really wasn't very hard at all. I managed to sneak the rear set of lines out past the loop on the back of the head, didn't have to take that off.

I gotta say, I'm a little disappointed. I don't feel near the boost in power that I thought I would. I'm not sure if I actually feel any or if I just think I do. I don't know if swapping from the HO pump to the SO pump a while back killed my power that bad that the injectors just don't make that big of a difference or what. I would have thought a 30-40hp gain would be noticeable even in something as heavy as my pickup. My bottom end power still sucks, but I think id did improve somewhat. With my old HO pump, I could hit 1100* egt and 21lbs. of boost. With the SO I could only hit 900 and 19. With the 275's my boost hasn't increased at all, but my egt's will hit 1000*. Will have to take it out tomorrow when I have day light to see if I get any kind of haze out the tailpipe. Does this all sound about right though? It does seem to run slightly smoother.

You have answered your own question. When you replaced the HO VP with an SO VP, you lost HP and TQ due to a loss in injector pressure. The SO pump does not put out as much psi pressure as the HO pump. Now to add further loss to the problem, you installed the 275 injectors vice your stock injectiors. The problem here is that the 275's have 7 small holes vice the 5 regular holes for fuel pattern development. With the HO pump you are able to take advantage of the 7 small holes with the greatter delivery pressure and have the ability to atomize the fuel more completely. The SO pump while not being able to deliver as much pressure as the HO pump does not have the ability to take advantage of this. So you see a decrease in performance.



With the above sceanaro we are talking in stock mode only. No chips or boxes or tapped fuel pump wires.



The 275's when coupled with the HO pump in stock configuration will yield about 30 to 35 more hp and you will see an increase in fuel economy of about 1 to 1. 5 mpg. Running the 275's the way you are with an SO pump on an HO motor you are loosing performance. This is sticking with a stock mode of operation.



The big differences in the HO and the SO motors are Injector pump pressure, higher in the HO, Pistons - higher compression in the HO and I think the ECM is a touch different.



If you still have your HO VP and it is good, I would re-install it and see what your difference is. I think you will be suprised. Otherwise I would install a HR-VP-44 in place of the SO VP. Tag on a Smarty and a Edge Comp along with a 4 inch exhaust and you will see a dramatic difference.



Thats my input. Good luck

 

[AFoulk]

My old HO pump is gone, it was giving me a dead pedal. As for my old HO injectors, I was always told they were slightly smaller than the the SO injectors. I havn't felt any decrease in performance with these new injectors, if anything I've felt a slight increase, just not what I was hoping for. And no my wastegate hasn't been messed with. Like I said above, it was set to 21psi from the factory, as I could hit 21 with my old HO pump. Once I went to the SO pump, 19 is all I could hit. With these new injectors, all i'm hitting is 19 yet, so theres no way my wastegate is opening yet, or setting an overboost code. Besides, I don't think the computer will set an overboost code until it sees about 26lbs. of boost.

 

[16919]

My old HO pump is gone, it was giving me a dead pedal. As for my old HO injectors, I was always told they were slightly smaller than the the SO injectors. I havn't felt any decrease in performance with these new injectors, if anything I've felt a slight increase, just not what I was hoping for. And no my wastegate hasn't been messed with. Like I said above, it was set to 21psi from the factory, as I could hit 21 with my old HO pump. Once I went to the SO pump, 19 is all I could hit. With these new injectors, all i'm hitting is 19 yet, so theres no way my wastegate is opening yet, or setting an overboost code. Besides, I don't think the computer will set an overboost code until it sees about 26lbs. of boost.

HO injectors are smaller... not a huge difference but they are. Thats why HO motors respond better to injector swaps by themselves (no boxes). I could get 23psi on mine stock... 30 psi with DD3's... . I would get a boost fooler and a waste gate elbow... you will need the elbow eventually anyways. I think the over boost is set at 24psi...

 

[Partyat33]

I would not recommend adding timing to an HO motor. Mine pinged with an EZ.

 

[AFoulk]

Finally got a chance to drive it good today. It definately has a little more power now. The bottom end is still a little soft, but it definately pulls a little harder on the top end, and my power band seems like it extended a little bit. It used to fall on its face after 2000rpms, now it atleast keeps pulling well past that. Oddly enough, it seems like they helped smooth things out when I get off the throttle real quick. The drive train lash used to make the truck shudder a bit when I'd get out of it real quick, now it doesn't do it. Maybe its just in my head too Anyways, its still not gonna set the world on fire, but it made the thing a little more barable till I can afford a box.

And I've got a boost elbow on the way, so thats taken care off.

Partyat33, I think thats what will make having a Quad Adrenaline nice, he'll probably have some files for it with reduced timing.

 

[johncameron]

Anyways, its still not gonna set the world on fire, but it made the thing a little more barable till I can afford a box.

And I've got a boost elbow on the way, so thats taken care off.

Boost elbow without a fueling box?

 

[Jed]

When I added the 275s by themselves I would get an overboost code and the check engine light would come on. I had no gauges at the time so I do not know psi.

Boost elbow fixed that. my only mods at the time were 4" exhaust and fass.



I have my old ez and if you want to try it I could send it to you pm if interested.



I am very glad I went back to 275s better mileage and truck runs smoother.



jed

 

[AFoulk]

Jed, I sent ya a PM