Okay, i have made my first step towards more boost. I bought a 2.75" pulley (7lbs) and a 2.625" pulley (9lbs) from ebay for $50 each. I thought that was a good deal considering Whipple wanted about $120 each shipped. I have been looking EVERYWHERE for a used 8.1L whipple intercooler and cant find one. Whipple wants like $2000 for thier kit, and i am having a hard time justifying that. I really want to get intercooled but im going to have to wait a few more months to save up the coin if i have to get it straight from Whipple. My truck is running VERY strong right now with almost no KR at 5.5lbs and with the stock pump. I realize i am in the extreme minority here with a blown 8.1L, and that most of you have the small blocks with the radix.....but i am sure you guys can help me on a few of these questions.

1. At what point do you think i will need to upgrade the fuel pump/injectors? I have heard the stock 8.1L pump is good for almost 450rwhp, and if i remember correctly, my injectors were at about 64%. Even with the 2-5/8" pulley i am not going to make 450rwhp i dont think, but i am not sure if it will max out my 43lb injectors or not.

2. What is the absolute maximum PSI i can run this at without an IC? I realize it depends on ambient outside temps and so forth, but i am just looking for a general idea is all. I know when i get this pulley, i am going to want to put it on right away, even though i probably shouldn't without the IC...

3. This is probably a no brainer, but i am going to have to hop back on the dyno for a tune to make the most of the new pulley correct?

4. Anyidea how much boost these 8.1L engines can take before any failures occur? If i rememer correctly, they are only about 9.1:1 stock, but i will have to go back and look to be sure. I know someone else here was running 12lbs on their 2500HD/whipple, but it was the 6.0L. Should I be worried about anything going to 9lbs?

Any suggestions are welcome, and i realize these questions can probably be answered in the first ten minutes on the dyno. I was just looking for some thoughts and suggestions before hand.

I know the 9lb pulley will send me into the 13's for sure....man this ****'s adictive..... ....any guess what i can make in the 1/4 with 9lbs?

If anyone knows where i can pick up an 8.1L I/C for less than $2000, PLEASE tell me.

Thanks.

 

I'd talk to Ryan23silverado, he has a nice I/C setup

 

I would put a meth kit on it. I got mine from Devil's Own and really like it. Cheaper then an intercooler, but still cools the intake air and adds octane to keep the knock away. I have an intercooler and though that would be enough, but now that I put the meth on there, I can run more boost safely on pump gas.

 

Linda,

You can probably go ahead and try the 7 lb. pulley without the I/C, since you're not seeing any kr now. If things get too stressful the knock sensors will detect it and pull the timing back. You also may not need a tune. I went from 3.7" to 3.25" on my Magnacharger without a retune and it was OK. However, if you have a custom tune and the tuner either went to speed density, or disabled the low octane table, you may have problems, so if this is the case you might want to ask them. Otherwise just take it easy the first few days and gradually increase the amount of throttle you give it. This will allow the PCM to recalibrate itself. At least it worked for me, ymmv.

 

Thanks, i think i will try out the 7lb'er and see how it acts. Turns out my stock pulley is actually a 2.875", which makes me about 5.5lbs. I thought it was a 3" originally. So it seems that the 2.75" will give me 6.5lbs, and the 2.625" pulley will give me 7.5lbs. That is if the .25" decrement = 1lb of PSI stands true. I am not to crazy about the meth injection (dont ask me why, no reason really) and would much rather have the I/C given the choice, but i will see how she reacts to the larger pulley and make a decision. Do you think there will be a noticable difference jumping 2lbs?

 

Why not just get a factory intercooler for a Diesel...you have a HD so it should fit(and they are huge). I've seen new ones on e-bay for around $150-$200 and then get a universal piping kit and some silicone connectors for another $200. You ought to be able to do it for around $500. I have heard of people using exhaust tubing to mock it up. I'm not sure about injectors, but I think above 44lb they aren't just plug and play, you have to adapt the harness and space the fuel rails out a little (easier than it sounds). Good luck

Dave

 

I have considered that route, however, i believe the core support on the DMax's are different. The downsides to this i think are that the I/C may be to large. Also, there would be a problem getting the correct manifold and blower adapters. I would most likely have to get them from whipple. If you look at the pics on my site (in my sig) you can see how close the blower outlet and manifold inlet are. It would be impossible to re-use these with anything other than the Whipple I/C. Take a look at this photo showing my setup on the left and an I/C'ed setup on the right.



The Whipple I/C setup has much shorter pipe routing than a DMax setup would have too. Of course im just speculating that the DMax I/C may be to big, I dont know that for sure. I have heard that to large of an I/C is as bad as none at all. I am welcome to opinions and suggestions. Of course if i did get the whipple I/C, i would remove those hideous "Whipple" graphics from the top.. . I am just having a very difficult time figuring out what to do next. I need the I/C, but am having a difficult time figuring which direction to go. If i could find an aftermarket I/C that was the same dimensions as the Whipple I/C, i could fab up some brackets and maybe get the tubing and manifald/blower adapters from Whipple. I think im just going to have to save up a little bit longer and get the Whipple I/C..... .

 

I know its been talked about a thousand times, but has anyone actually ever installed a DMax I/C into a non diesel HD or 1/2 ton truck? I have searched and only found threads of people who were going to do it but never did. Do you think it would be to big and cause some lag? I know they are designed for 30+ PSI, thats what worries me, i would only be running a 1/3 of that at the most. Also, there is the issue of getting the correct parts to bolt onto the blower and intake manifold...... .....i dont know, just talking myself in circles here. Oh, and if anyone knows where to pick up a used Whipple I/C, that would be awesome, i cant find any!

 

Linda,

You shouldn't have any problems at 7 psi non-intercooled, just make sure the tune is solid and *do not* rely on the knock sensors until you are sure of the tune (I'd hit the dyno, myself -- it's cheaper than a piston land ).

I'd skip the whipple IC and get an A2W intercooler and have a fab shop make the piping for you.

 

I will most likely hop back on the dyno either way. The Whipple I/C is A2W (air 2 water), the DMax is not. Even though i will probably be okay @ 7 PSI without it........the cooler AIT's and more HP are what was drawing me in. It can get quite hot and humid here on the east coast in the summer, and even though this is not my daily driver and summer daytime temps wouldnt be to much of an issue.....i do use it for camping trips into the mountains. I definately want to go the I/C route, its just a matter of how right now. I would love to bump it to 10psi once i get the I/C. Anyone know how well the 8.1L do holding up to increased boost levels?