vvv90

the ATI rep said my P-1SC or P600B head unit can be upgraded to a D-1 or D-1SC for $1,000. Has anyone done this or is he just trying to blow smoke up my azz. I'm about to invest a lot of money into this s/c I want to make sure it won't be too expensive to upgrade.

ForceInjection

The upgrade on the head unit should only cost about $500-$600

krivera

i agree it should be cheap only 500 or 6? but then again ATI told me i would have to sell my D-1 out right and they dont do the up grade THANG! :confused:

vvv90

So then is the upgrade done by ATI? I'm wondering why they would tell me something different.

gcrouse

The P-1SC/P600B kit is can be upgraded to a D-1/D-1SC head unit at the time of purchase only. ATI has no upgrade program for used head units! Believe me I've wished for this....

vvv90

Then why the hell did the guy from ATI tell me I could!?!?!?!? If it turns out you're right I'll be pissed! I'm not going to do business with a company who's going to lie to me about what I can or can't do with their product. I'm calling them back to see if I can get that in writing.

vvv90

I just got off the phone with ATI. They said they do have an upgrade for the P-1SC to a D-1SC for about $1,000 because they have the same transmission and it just needs a new impeller. He said the P600B cannot be upgraded to the D-1 because it's a completely different unit. I'm still a little wary because he said their's nothing outlining the upgrade in writing.
hmmmmmmmmmm.

gcrouse

My experience with ATI is with the P600B/D-1 and yes, they are completely different units. Sounds like the SC series is standardized with same transmission and compressor housing; like you said it would be good to have in writing though. On another note- $1000 to upgrade your used head unit versus $1800 for a brand new one....hmmmmm

vvv90

I know! What a rip! Oh well, I don't really have a choice. I could probably sell it in a couple years for $1,000, buy the new one for $1,800 and save $200. :rolleyes: Oh well, at least there's an option that exists that will save me a little money.

gcrouse

I know I'm late in suggesting this (didn't read the forum last week); but I think you could have reduced the boost of D-1SC enough using the largest blower pulley (3.25" I think) plus an underdrive crank pulley (March, ASP, etc.) Throttle response wouldn't be as good and you might have lowered the efficiency of the blower (they should be correctly sized to the airflow requirements), but you'd avoid that upgrade fee.

Oh well, live and learn. I've got a hungry 383 with a P600B which because of the low step-up (3.05) I can't get the impellor anywhere near max to get full airflow. Wish there was an upgrade for mine :cry

AKS Racing

George,
You state that you can not get anywhere close to max impellor speed with the P-600B. Seems I recall that I had to actually slow the impellor (went to the next size up pulley) when I changed intake and cam on my old combo. What are you twisting your combo to? Many of the long runner intakes will never see max speed (32,940 @ 4800 crank RPM) due to the low crank RPM. That is why ATI came out with the D-1 as an option on the L-98. Three years ago, that head unit was not available in a kit for the L-98. I think the max impellor speed calc went something like:

Max imp speed = RPM * [crank pulley dia/blower pulley diam] * step up ratio

= 5800 RPM * [6.75"/2.5"] * 3.05 = 47,763 RPM

Taking the same system with the D-1 (4.44 trans) yields:

= 5800 RPM * [6.75"/2.5"] *4.44 = 69,530 RPM

Remember that max impellor speed for the P-600B is listed as 60,000 (while ATI says it can take 62,500) and the D-1 is listed as 65,000 (while ATI says it will handle 68,000). Now think of moving to a short runner intake and twisting that same combo to 6500 RPM. The new formula is rearranged to become:

[(6500 RPM * 4.44 * 6.75")/65,000 RPM] = blower pulley diam = 2.997"

Effectively choose a common size available (either 3" or 3.25"). Allowing for the potential of a missed shift (say 7,000 RPM), the size must be set at 3.25", yielding a 59,940 speed at 6,500 RPM, or 64,551 at 7,000 RPM.

Remember, none of these are exact, but they give the general idea. Also, I forget the exact size of the factory crank pulley diameter (I hope none of our blower attendees are running underdrive pulleys on the crank). Nevertheless, the above calculations should be close.

Aaron




[Modified by AKS Racing, 7:42 PM 8/19/2002]

vvv90

Actually you're not too late, I've put off another day sending out my cashier's check. I've got until the end of the month but I want to send it out today. I like your idea but I'm a little wary. I'd like to see if there's someone out there who's done this. I'd hate to spend $4000 on an experiment, because if it doesn't work like I thought, I'd be out a lot of money. :cheers:

Blown Vette

This would be a good chance to deal with a major Procharger dealer. Call ASSC Racing in Lake Bluff Ill. and talk to Larry. They are the best choice to get real information and purchase a kit from. The knowledge you will gain from dealing with them will far outweigh any savings on a kit. Good luck and remember to order from ASSC.

847-473-4720

gcrouse

Aaron- I'm hydraulic roller and cast crank so my redline is 6000rpm. Pretty sure the stock crank pulley is 7.0" so with the small 2.65" blower pulley that came in my 12psi kit:

6000rpm * [7.0 / 2.65] * 3.05 = 48,340rpm impeller

Assuming the belt doesn't slip (yeah, right), the P600B will flow a maximum
of 1200cfm @ 60,000rpm; and since air volume varies with the square of
impeller rpm:

[48340/ 60000]^2 * 1200cfm = 779cfm not even 2/3 of its capacity!

Assuming a good intake, the blower cfm doesn't surpass the NA 383's cfm requirement (at 85% VE) until 4400rpm; in fact it doesn't actually pressurize the cylinders (> 100% VE) until 5200rpm!

Since my ignition cuts at 6000rpm, I'll never get close to that 1200cfm and
150% VE the blower is capable of. Losing 11K of impeller rpm off the top
really hurts on a centrifugal compressor (since it's rpm squared).

I need to hit the full 60K impeller at 6000rpm, but at 3.05:1 it's really
geared too low. ATI is sending me a teeny 2.25" pulley which should get it up there around 57K and 1100 cfm; if the belt doesn't slip horribly (yeah, right). Which of course brings us to Danny's thread about his homemade manual tensioner assist.