Help me size my turbo upgrade!

[crownvic96]

ok this is going to go on an '87 GN. its going to be a daily driver. with a few passes at the track just to get it dialed in.

mods it has now or will have when i order the turbo. i figure if everything goes right i should be ordering the turbo around late may early june depending on weather and my schedule.

stock long block
4" CAI from buick GN, 3" MAF,3" maf pipe, trans+, 3" up-pipe, PTE stock location intercooler. 72mm throttle body, ported upper and rjc power plate. mototron 60/65 high z injectors, adj fpr, racetronix hotwire and walbro 340 fuel pump. rjc billet pulley set. turbotweak chip. rjc and greddy electronic boost controller. TH3"DP with stock wastegate, test pipe, ATR 2.5" SS exhaust.
stock transmission(if it lasts, if tranny lets go i'll get a upgraded 2004r with a higher stall lockup torque converter)

suspension is bilstein shocks, replacement stock height moogs, HR parts lower control arms and anti-sway/roll bar, removed pinion snubber, dual air bags, 275/50/15 drag radial. trunk brace and front brace.

the one big variable i don't know about is if i want to put alcohol on it. right now i'm leaning toward yes. but if there's a turbo that would have enough flexibility to handle some extra boost with tha alcohol that would be great. if not what turbo's should i look at for having alky and not?

money is not really of any concern either. i just want the best turbo to match what i have.

 

[bruce]

Originally posted by crownvic96
ok this is going to go on an '87 GN. its going to be a daily driver. with a few passes at the track just to get it dialed in.

72mm throttle body,
stock transmission(if it lasts, if tranny lets go i'll get a upgraded 2004r with a higher stall lockup torque converter)

IMO,
You have too much throttle body. Smaller makes for better street manners.

Stock Converter?.
Then I'd say a *62* turbo. Much more, and it will really seem lame.

A looser converter and 60-62 would be lots of fun.

I've got pretty much the same setup as you, and have been running a stock converter for several years, and while OK, similiar setups with a looser converter really *rock*.

 

[crownvic96]

Re: Re: Help me size my turbo upgrade!

Originally posted by bruce
IMO,
You have too much throttle body. Smaller makes for better street manners.

Stock Converter?.
Then I'd say a *62* turbo. Much more, and it will really seem lame.

A looser converter and 60-62 would be lots of fun.

I've got pretty much the same setup as you, and have been running a stock converter for several years, and while OK, similiar setups with a looser converter really *rock*.

i didn't know the TB would hurt any street performance. thanks for the heads up. i just figured since i had 3" piping everywhere else to just match the TB to that. I don't have the TB yet, i was gonna buy the upper/tb/power plate combo from rjc. maybe i'll just hold off and get a power plate and a plenum if there won't be any significant gains to be had from the larger throttle body. especially if there are drawbacks on the street with it.

when you say 62 to do you mean a 62mm or is there any specific ta or te style? i'm really not that familiar yet with all the GN type turbos. i've spent most of my time researching everything else for my car. maybe i'll do some more researching today on it. works been slow.

 

[bruce]

Re: Re: Re: Help me size my turbo upgrade!

Originally posted by crownvic96
i didn't know the TB would hurt any street performance. thanks for the heads up. i just figured since i had 3" piping everywhere else to just match the TB to that. I don't have the TB yet, i was gonna buy the upper/tb/power plate combo from rjc. maybe i'll just hold off and get a power plate and a plenum if there won't be any significant gains to be had from the larger throttle body. especially if there are drawbacks on the street with it.

when you say 62 to do you mean a 62mm or is there any specific ta or te style? i'm really not that familiar yet with all the GN type turbos. i've spent most of my time researching everything else for my car. maybe i'll do some more researching today on it. works been slow.

With the large TB, you lose having any real throttlibility at the higher openings. From 3/4 to WOT, there's just no real change.
So you have to back way off the gas, to get the car out of say a bad wheel spin situation. Then at the lower Throttle openings, the TV Cable, to load relationship changes. If you're running like in the 10s, then maybe you'll find a *little* gain, but for the street, IMO, the 3" Butterfly is just a lil too much.

TA, or TE, there's no real difference between the two. According to Limited Eng, there's only about 4% difference between the two.

 

[crownvic96]

so if i wanted a ball bearing turbo according to the garrett turbo catalog on limits website i'd want the GT35R with the .82 A/R?

i figured i'd have more responses than this on here so i guess i shall just get in contact with precision and limit directly and see what they offer.

btw thanks for the tip on the throttle body Bruce.

 

[salvageV6]

Some things you might want to think about BEFORE buying a turbo would be the following:

1. How long is my stock tranny gonna last unrebuilt? What stall converter do I want for street duty and some track duty when the rebuild happens? Lockup or non-lockup?

2. No heads and cam listed, or in the future?

3. HP level desired on the stock longblock?

4. If I won't be running alky., or high boost often, is there any reason to go larger than a 44 turbo at this time?

5. If you go with the alky. better decide what stall you will be using before you buy it and you will have to live with no spoolup on a larger turbo until you get the converter installed.

I like BB turbos on the street to help eliminate some of those loose converter and spoolup issues.

I also don't think I would like more than a 3200 stall for daily driving and it should be a lockup too for better mileage.

Your future use and power level would help determine what clutch size and material IE: 11 inch single, 9 inch single, 9 inch multi-disk, etc.

Sounds to me like a single disk 9 inch lockup would work for your goals so far.

I would clarify them before buying a turbo.

 

[2QUIK6]

AS all mentioned above, a 61 or 60 series turbo will work great on the street with a 3000 or 3200 stall convertor with lockup. As for the turbo and alky...it doesn't really matter, the alky will let you run higher boost with any turbo on pump gas.
Now that high# may be a little different depending on turbo size.....take a stock turbo...max boost on pump gas for my setup was about 17#. Slap on the GT6131E, and I can go 20# on pump gas no alky with no KR probably because the charge is much cooler with the bigger turbo. And alky and I'm sporting 24-25#. Another thought, the 60/61 turbos really come alive at 24# and pull hard, so keep that in mind in your consideration.

 

[crownvic96]

Originally posted by 2QUIK6
AS all mentioned above, a 61 or 60 series turbo will work great on the street with a 3000 or 3200 stall convertor with lockup. As for the turbo and alky...it doesn't really matter, the alky will let you run higher boost with any turbo on pump gas.
Now that high# may be a little different depending on turbo size.....take a stock turbo...max boost on pump gas for my setup was about 17#. Slap on the GT6131E, and I can go 20# on pump gas no alky with no KR probably because the charge is much cooler with the bigger turbo. And alky and I'm sporting 24-25#. Another thought, the 60/61 turbos really come alive at 24# and pull hard, so keep that in mind in your consideration.

sweet thanks.

 

[cdsttype]

I would have to disagree with the throttle body choice.
Ive run a 58 a 62 and 70mm tbs with a stock trans and
60 size turbo properly tuned is no problem on the street.
If anything i had better part throttle response with the 70mm.tb
The 60 turbo worked very well on the street my choice
would be 3 inch tubing everywhere you can go all the way
to tso with that set up.