Hey guys.... There is going to be a 275 radial class in my area. Rules state max of 88mm turbo. Which turbo would you guys run with 434 cubic inches and which a/r exhaust housing? Hoping it will go 8.20's or so.

 

John Kolivas
white cobra331

thats who i would PM. He has probably tested more 88mm turbo combos than anyone i can think on. My educated guess for an off the shelf turbo would be the gt47-88 with the larger housing (1.23 ish) there are numerous custom made turbos that might be better- but i am not sure what the rules are-- john will know them.

 

With your CID and if you still had your pt-101 send it to Precesion to have a 88mm wheel put on it or if you are allowed to use a restricted cover with a larger comp wheel, do that. I would not use a gt47-88 or similar due to your large cid, you are familar with spooling the large turbine, and you will get more air through the engine with the larger turbine thus making more power. But that is just me.

 

I am trying to keep both setups. 315 MT Radials and 101 / 275 MT Radials and 88 depending on which event i am running. So i want to have 2 turbo's to swap in/out.

 

What do your rules state... 88mm inlet or 88mm tip to tip on the compressor inducer? I know that there would be less tuning changes between turbo swaps if the turbine wheels were the same in both turbos. How sweet would it be if the requirement was the 88mm inlet then you may be able to have precesion make a comp cover for your 101, to neck it down to 88mm? I have no idea if they neck them down that far, but then it would be a comp cover swap.

 

Here is the rules so far....

Extreme 275

1. any type suspension, stock rear frame rail , stock front frame rail
2. engine combo's
A. big block short deck, conventional head only
B. no boosted big blocks
C. single carb only
D. no sheet metal intakes
E. no alcohol
F. engine diapers recommended (if you oil down, diaper will be mandatory next appearance for you)
3. Power adder
A. single power adder only
B. nitrous: 2 stages max on both small & big block
C. Blowers: approved F1R, XI trim or smaller
D. Turbo straight 88mm only!!! (gt47, y2k allowed) no hybrids must run 80mm reducer sleeve measured at inlet
4. 275 max tire size as printed on the side wall radial tire only.
5. 3200lb base weight for all combos.
A. nitrous smallblock deduct 200lbs
B. N/A cars deduct 500lbs
C. all weights are with driver
D. must weigh in after each pass
6. NO WHEELIE BARS

 

88mm and a 80mm reducer sleeve? That is a weak description of the allowed turbos. No hybrids? Curious to know if anyone has tried the 88mm comp comp wheel on a f or g trim turbine. I guess that would be a hybrid.

 

Hey John, where is this class going to run?

 

Yeah,,that is a weak description .at first they say only 88mm turbos then go to a 80 mm sleeve.do they have a site where you can ask for more clarification?
if you must go with a 88,then id say a gt4788..i bought mine from John Kolivas after he had done some testing,thinking at the time NMRA was going to allow them,only to find out they weren't till the following year.

you will have to do a lil re piping.it is a lil smaller than a large frame turbo,but still uses a T6 flange.

 

Couldnt you do a PT98/88 and then sleeve it?

 

Depends if they let him sleeve it..if so.hell he could sleeve the 106 he has now

 

Was wondering the same thing. I figured if he didn't change his turbo out he could help me again.

 

OHHHHH stop it Marc! It's not always about you! You're as bad as Mike...must be a chevy thing!

 

that is just rediculous!!!! you can have a gt47-88 but with a 80mm sleeve????wtf is that why dont they just make it an 80mm turbo limit and completely discourage any turbo car from getting into the class

 

Maybe the sleeve thing is a typo

 

nope the nitrous guys around here are hating on the turbos

 

Yeah i didnt really get the rules. But i dont know if im gonna run the class now. I dont want to buy a new 88 and then have to sleve it down to an 80.... Ill just try and blow up the junk I already have I guess