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Questions about ported/polished stock twins...

498 Views 11 Replies 4 Participants Last post by  pooshda
Well I bought a pair of modified stock twins from a member of the board, they are ported/polished and clipped 10 degrees I believe.. they should be here tommorrow or thursday and installed soon after... but I have a question.

I was told they should flow about 15% or more over the base stock twins.. does anyone have any idea what kind of horsepower increase these things would give me over the non-modifieds stock twins? Ive been looking around for info.. I mainly got them because they had no miles after the modified rebuild, and because they should spool a little faster.. Im not sure if I should expect a significant power increase or not.

So thats why im asking.. dont know if I should expect a decent boost in power or not, or if they should just spool up awesome.. Anyone have an idea? Thanks.

Oh yea, and btw... I would find out myself, but we dont have a dyno anywhere closer than 3 hours away, so I cant go dyno the car :(
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Hey, PM or email Ybslow1. I'm pretty sure that's what he had done to his car, and it hauls ass!
I tried e-mailing him... didnt work, no private message yet..

Anyone else?

Someone is selling modified ones in the for sale forum right now and claims they are for upto 600hp, thats sorta hard to believe.. do you think I could get 30-50hp with ported/polished/clipped 10 degrees? or is that a low or high expectation?

I just want an idea, and I have not been able to find any info on modified stock twins anywhere... ah well, I know ill like them.. but I wont know what kind of power I have since there are no dynos locally :(
I'll give him a call tomorrow and ask him to get back to you
Cool thanks... yea just tell him I sent him a Private message on here... I got errors from my mail server both times I tried e-mailing him, so I gave up :)

Wish there was a local dyno so I could see what I have anyway.
Ported Twins

What's up Pooshda, sorry it took so long to get back with you. Well I had my stock twins re-worked without any problems as of yet. But their are two guys I know of right of hand that had their twins ported and both of them had their turbine shaft pop right out of the housing, but they both had their twins worked at the same place. So just be careful who works on your twins. My car can hold 24PSI without a problem, on warm days it drops off to about 22. I dynoed up in Michigan about a year and a half ago at 390 rwhp and 410 ft Lb of torgue on my new reworked twins. I did notice a quicker spool response and seemed to add more power. I still need to dyno my car now that I am BPU+, just waiting on my fuel controller to arrive to tune to the running rich problem BPU cars seem to have. I will keep you posted.
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Thanks a lot for the reply... was the 390hp BEFORE you were BPU? those are some damn good numbers... my car is basically BPU.. no intake or boost controller yet though.

Do you think I can safely run mine @ 18-20psi on Premium pump gas? mine were modified by Majestic Turbo ive heard great things about them.. so im guessing they should be good.. ported/polished/clipped 10 degrees.. I may give them a call too to see if they have an idea.. again, thanks for the reply I cant wait to get them on... hopefully they arent overported or anything...
the 390 dyno was actually rigth after I installed my new turbos on 101 octane gas, boost was tuned to 19PSI. you are going to love the sound of the ported twins, man they whistle well.
only 390 @ 19psi for modified stock twins??!!! I've heard nothing but bad things about modified stockers, couple of friends have had them and they show little or no stock twins @lower psi pulled on his modifieds @ higher. But its your decision.

Oh well Ill judge for myself soon.. I got them yesterday.. I was told I probably wont gain much power.. BUT some advantages I was told about were quicker spool up.. about 400pm quicker, any little bit is helpful.. plus I called a Turbo place and they told me I could run 20psi RELIABLY instead of risking pre-mature failure of the unported/polished stockers...

Basically just knowing that they wont die on me from 18psi or so is enough reason.. but I got a good deal on these in my opinion, the seller worked with me on the price... im not expecting much more than maybe 20hp heh... but I just like the idea of not worrying too much about overboosting at BPU levels.
YBSLOW1, when you had the dyno pull of 390rwhp, what were your mods at the time? Just curious. If you didnt have anything done other than a BCC that is pretty good. I have never heard good results of modifying the stockers, has something to do with the shaft being so small. Where were your twins upgraded? I have heard great things about Majestic Turbo(Waco,TX)as much did the upgrade run? Can they fit any different compressor wheels into the CT12's?
Im not 100% sure.. or if Majestic even really did anything but polish them... they seem pretty normal upon visual inspection, but are a lot more polished than stock form.. dunno about the rest..

I ripped the old turbos out today and #2 definately has a nice wobble to it when I spin the wheel.. #1 appears fine other than rough edges on some of the fins.. and small little chips, just wear I guess.. but it spins fine and there is no real play.. so im not sure... Im pretty sure the new ones are fine too, but ive never messed with a turbo before, although im getting help from a friend.. you seem to be able to move it a VERY VERY tiny bit, but nothing like the blown #2, so im sure thats normal.. and when it spins its 100% perfect... they will be on tommorrow im getting up in 5 hours to install them, so I better goto sleep.. but Im sure ill like them, although ist hailing tommorrow so I cant enjoy them until next week :(
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