Pros and cons of single VS twins

[N2BUICK]

Having some time to think(scary) Was thinking why don't I just go to twin turbos from my current 4bolt PT-88?(stageII motor and heads)Race only car.

I have the ever present torque converter issue(to tight low,slips on big end)Does this get better with twins???????
I don't race in any class.Have heard that twins are not allowed in some classes.???
I need to buy some good non ATR ,single turbo, stageII,headers,anyway,The ones I have are borrowed!
Clearance to fender wells??I don't run a passager side,but need to put in back in(interfers with big remote oil filter)
Twin intercooler??
Buying two turbos and wastegates?? (my PT-88 and big HKS gate should bring $$$?
Replumbing oil supply and drains??

Just some thoughts,would appreicate anybodys input
Thanks
Austin

 

[turbodave231]

My thoughts:

2 turbos
2 wastegates
+ custom downpipes
custom intercooler
lots of plumbing
______________
lots of extra headaches, fabrication and expense
but it looks way too Cool!!

DR

 

[KendallF]

I had the same thoughts..and some of the parts so I went that route. I don't regret it...though I bet I'd have had the car running a while back if I'd gone w/a single! I think so far I am ahead on the money this way; largely because I scrounged for every last damn part and fabricated what I couldn't scrounge.

 

[EightSecV6]

My thoughts are:
BIG Single turbo=more power and initially cheaper
BIG Single turbo=slow spool up, forget about REALLY racing unless you step up to a clutch or a FB glide,that will DEFINATELY offset the cost of the twins.

Twins= spool like mad with the right exh hsgs and converter
Twins=no place to REALLY race other than brackets or the Buick exclusive races.

Bill Anderson

 

[John Wilde]

Mr. Anderson's Race Car

Bill,

Can you give us an update on your killer new race car?

Thanks in advance!!!!

 

[zturbo]

A lil diff for me but I personally choose twins on my camaro cause of spool up (was going to do a 88 or 91) but went with twins and should be finished with it soon. I am running twin intercoolers but do not see the need on a GN there is alot of room in front for a big intercooler with 2 pipes routed to it. Now i run 2 air-water setups and they fit in very nicely. I went overkill on the wastegate issue personally (Innovative progates)

Like above stated single will be a lil lazy on the spool up but the twins should hit boost faster and be alot more fun to drive. Doing the twins I honestly think isn't that bad in the long run moneywise.

Steven

 

[EightSecV6]

Well John,
Car is (almost fully!)painted, engine,clutch,trans and linkage are in. Currently back in the chassis shop to finish up the tinwork and Lexan. When I get it back, I need to plumb and wire it. We plan on hitting it hard in January, very difficult for me to get anything done on it with the hectic schedule at the shop.I just sold the street car in order to put full effort completing the project (one is enough!!!)
Honestly, it looks like a Brand New state of the art prostock car with a Regal body, hard to describe, most will be amazed at just the sight of it!!!! Sure hope it runs!
Thank for asking, (it motivates me)
Bill

 

[REDS HOT AIR]

Hey zturbo....

do you remember a link to this guys Iroc you have a pic of ?

this one

I been there before but cant seem to find it again.

thanks....RED

 

[N2BUICK]

Originally posted by EightSecV6
My thoughts are:
BIG Single turbo=more power and initially cheaper
BIG Single turbo=slow spool up, forget about REALLY racing unless you step up to a clutch or a FB glide,that will DEFINATELY offset the cost of the twins.

Twins= spool like mad with the right exh hsgs and converter
Twins=no place to REALLY race other than brackets or the Buick exclusive races.

Bill Anderson

Bill
Your comment on one big turbo,are you saying that I will never be able to get a converter to work? REALLY racing I guess means having a combo you don't have to start building boost,back in the staging lanes!
They say you can put the "FB" on a TH400,but it harder to do,and I assume even more $$
Thanks
Austin

 

[EightSecV6]

Austin,
When I said big, I was referring to the "thumper" style turbo, PT90 PT98 PT106 and so on. The 88 will work well with a standard conv and trans, it will not however make the same power as twins. Hope this clarifies things.
Bill

 

[zturbo]

Hey zturbo... do you remember a link to this guys Iroc you have a pic of ?

I got it off the web i think i might have the link i have about 6000 links so i am going through them but don't see it yet.

Steven

 

[N2BUICK]

Originally posted by EightSecV6
Austin,
When I said big, I was referring to the "thumper" style turbo, PT90 PT98 PT106 and so on. The 88 will work well with a standard conv and trans, it will not however make the same power as twins. Hope this clarifies things.
Bill

Bill,thanks for the reply.
I loose sight of what a "big" turbo is.I think that an 88 turbo is big!
Do you know of anyone using a 101 or a 106 on a V-6 Buick set up? They seem to be popular with the V-8 ford crowd.I think our little motors would not do one justice.
Thanks
Austin

 

[86brick]

Austin, Dale Cherry (who has run 8.30 @165mph) is using a PT-100mm turbo on his Stage II V6 GN.... He has a special variable speed stall FB Tranny....
http://www.fbperformance.com/techtips/newtip.html

Also, I'm pretty sure Lawrence Conley had a pretty big single turbo on his Stage II V6 powered "Tweaked" TR that ran mid 7's and also I know back in the day Jimmy D' Alessandro had a big Ferris wheel single turbo on his Stage II V6 that ran 7.61 @180+mph.... It has be done, but it's probably easier with some twins!

 

[EightSecV6]

Dale has the FB glide and he spools up pretty fast but that price of the trans far offsets the cost of the twin setup.Conley and Jimmy D always had problems spooling, Lawrence finally got it worked out with the Big Brute trans but if you ever noticed they had it in and out of the car CONSTANTLY, he fought it for a long time and eventually went 7.75, I didn't think D'allesandro went a 7.6? but I am probably incorrect
It is all a matter of preference (or class racing)and how much you want to spend.
Bill

 

[summit]

Dale actually runs a 91 Outlaw turbo unless he has changed very recently. we are also trying to work out the stall vs topend on a 91 mm buick here, but are having a tough time. However we seem to have the perfect combo in my 88mm "street" car as you have already seen. One thing we have looked into recently is Precision Convertors offers a lockup turbo 400 transmission now with a 5 disk lockup rated for BIG horsepower (1200+). It is kind of pricey with the conversion kit running $2800 with convertor, special pump and shaft, and special transbrake valve body. Why don't you try it and let me know how it works out for you?? I would but I am kind of leary of trying the precision convertor on a car of our horsepower levels. I wasn't too pleased with the durability of their convertors on other 1000+ cars I have seen. They don't have steel ststors available for their convertor and still use aluminum. Durability issue?? Benefit would be allowing you to use virtually any stall you wanted and have 100% efficiency on the top end. A little cheaper then the FB tranny that only yields 600-1000 more stall rpm.
Greg Kring

 

[Jesse]

I was thinking of running twin turbos on my S2 instead of a 76 or 88, But my only concern is street driving. I would like to drive my Gn on the street once and awhile (fri & sat nights mostly)
Would there be a problem with it.

Thanks
Jesse

 

[Turbo231]

I'm in the same boat as Jesse.
I am trying to finish my SII and need headers.
Right now it's a what works for the best price deal.
Single looks easier but twins sounds better. (more HP)
Also when I cruise it never fails....
"Hey is that one of those twin turbo Grand Nationals!?"
So if someone wants to sell me some headers at a good deal....

 

[86brick]

Bill, I know for a fact that Jimmy D went 7.61 @179+mph cause a good friend of mine who lives in Jersey saw him make the pass a while back and also if you have a Poston catalog they mention him running these times cause he was using a Poston sheetmetal intake....

Greg, maybe Dale will chime in cause I know he posts on here from time to time (his user name is Quick86GN), but from what John Wilde said he is using a PT-100mm single turbo!

Jesse, you might want to speak with KendallF cause he is in the process of building a twin turbo Stage II TR which he plans on street driving and he had mentioned a twin turbo Stage II GN that he saw at Reynolds that was running 8.50's with very small 38mm turbos (basically stock hotair turbos) and if my memory serves me correct this car weighs 3400+lbs and is street driven

 

[EightSecV6]

Didnt realize he went that fast??? I know for a fact however, Ruggles built the intake on Jim D's car to match the HEAVILY modified M&A heads they also did. I spoke to Ruggles once about this and he said the flow numbers approached those of a good set of S2's. Ski from PA owns the entire engine, headers, manif. etc out of Jim D's car

 

[86brick]

Bill, here is what is said in the Poston Enterprises catalog....

POSTON ENTERPRISES TURBO REGAL SHEET METAL INTAKE MANIFOLD

"The ultimate intake manifold for a full race application. Produced 1,075 horsepower at the rear wheels and 1,400 horsepower at the motor. Same engine produced 1,000 lb./ft. of torque at 5,200 rpm. 7:61 ET at 179.78 mph in Jim D' Alessandro's race car with a single turbo. Manifold specifications: Sheet metal aluminum design. Tunnel ram design. 6" runner length. Plenum upper half removable with larger plenum volume upper sections available. Mono-valve adaptor plate included (Blank bolt pattern for any mono-vlave). Mono-valve throttle cable bracket provided. Fuel rails and mounting provisions included. Thermostat and sensor locations provided. 3/8" thickness on manifold to head flange (can be milled). Optional ideal air entries for port inlets available- will flow 98% of a cylinder head with ideal wood entry. Six pieces installed are $275.00 extra over cost of manifold."

Jim D' Alessandro/FIRST SINGLE TURBO INTO THE 7'S

POSTON ENTERPRISES TURBO REGAL ALUMINUM SHEET METAL INTAKE MANIFOLD, #PE648942, $2,688.00.

All I really know is Jimmy D had that TR hauling some serious ass!!!