Can I spool a 70GTQ?

[aquickv6]

Engine is back in and looking for a turbo, I would like to see 132 MPH and was wondering if I could spool a 70GTQ or maybe stick with a 70 super Q ball bearing.

Full weight T/R, 109 std, JE pistons, 3 steel caps, balanced, all ARP studs and bolts, champion ported big valve iron heads w/ ported intake, 206 Weber roller, 70mm TB w/ RJC plate, precision plenum, 83# injectors, TH 3.5" DP, Cottons FMIC, in tank DP. 3.42 rear, TH400 w/ brake.

I need the turbo and converter to complete. What do you think?

 

[CPAKCP]

aquickv6,

Our combinations are pretty close. Same heads and cam on a stock 109. I'm running a GTQ 70 with a CA. Performance Type N
NL converter / stall 4000. I was running a PTE 64E turbo with a Precison 3200 NL, and it was a lot easier to spool/ and to 60'. The GTQ 70 has made more power, but it's gonna take a harder launch to match the 60'(s) I had with my 64E.

Your mph goal will be easier with the GTQ 70, but if you really want a good ET, it takes a 4000 stall and the use of your trans. brake. You didn't mention what engine management systems you are using. My results so far have been with chips, I'm switching to FAST, and I'm hoping for a quicker spool up tune.

Good Luck

 

[aquickv6]

I have been with chips so far, but plan to change to a MER this season. I was hpoing to be about 3500 non l/u on the convertor, like maybe an Art Carr. I would like to come up on boost almost instantly. The GTQ would give me MPH but spool was a question. Maybe with a RJC boost control valve?

 

[rtviper]

AQUICKV6 Look in the Pacific Northwest Region for a list of parts just put up for sale many of the parts you just mentioned are in that list

 

[CPAKCP]

Originally posted by aquickv6
I was hpoing to be about 3500 non l/u on the convertor, like maybe an Art Carr. I would like to come up on boost almost instantly. The GTQ would give me MPH but spool was a question. Maybe with a RJC boost control valve?

I think if you check with most tranny vendors the 4000 stall is just about the minimum for the 70 GTQ. I got my advice from Lynn Freeman a tranny builder in LV,who races Buicks and has used this turbo. I was running a 3600 NL before I went to the 4000, it wasn't enough.

If you got with the RJC boost control let me know how it works out.

 

[azgn]

I have used both the Limit 70GTQ and dual BB 70.....on my car (with Art Carr "N" stall) the GTQ was difficult to spool.....I ended up with a Limit 70GT P trim that spools great and makes lots of power (with this turbo and 25 lbs have gone 10.4's @ 129......130+ should be easy with more boost) no question the GTQ makes more power, but the BB will win the drag race for you
(BTW, I use the RJC bleeder and my car wieghs 3700+)

another example- on Nick M's car (274cu alum block) the GTQ ran 9.8's@140 and the BB70 runs 10.1's@134

 

[Fuelie600]

Looks like a 50-60 HP loss going from the GTQ to the BB with the same compresser wheel size. Hard to believe there is that much difference. What other differences were there in those turbo's? Exh, housings? Boost run? Air temps? Trying to understand what's making the difference. Thanks Brian

 

[CPAKCP]

azgn,

What exhaust housing are you running on the Limit 70GT P? Does it have a 4" inlet and a 3.5" outlet? Do you think the RJCbleeder
would have helped on the GTQ?


Thanks for the info

 

[azgn]

no difference in boost......temps & track conditions the same.....remember, on a smaller displacement, lower flowing headed engine that difference may not be the same

bottom line, on Nick's motor, the 70BB is done at about 25 lbs boost....that should tell you something

I never had much luck with the GTQ (same turbo) on my car ( ported GN1's & 231 cu)

we saw the same difference on D!ck Kereny's TSM car.........but he was running much higher boost

 

[azgn]

James

.83 Precision P trim.....small compressor housing (not the "S" housing) 4" in 2.5" out...it is a puny looking turbo, but kick's some serious booty

I had the bleeder installed with the GTQ....I feel better flowing heads and/or more displacement is needed to really spool the GTQ....to drag race with the GTQ, I had to stage very hot (like 3000 rpm) to get a decent launch and reaction time...the little 70 will leave at 4000 rpm after the 2nd stage lite is lit

 

[aquickv6]

Woody,

Which turbo are you suggesting for my combo ? (as listed above)

What do you think would be the difference between the Limit 70GT P trim with .83 housing, compared to the 70 BB Q trim.

Thanks for the help.

 

[azgn]

I honestly think the little old Limit 70 makes more power than the BB70....much cheaper (about $1K vs $1.5K)

the BB spools easier, but with the right converter, the diff is insignificant

talk to John Craig about the turbo I have....I would recommend it for you

 

[aquickv6]

Thanks Woody! I will talk to John, it sounds good.

 

[Fuelie600]

Some very knowledgable guy's in the Buick world told me quite the opposite. The GT turbos are better spooling but are all done after 23-25 psi. This is where the non-GT turbos are better. This comes from a source that I have trusted and who has been a major factor with TR's since their begining. Who's BB were you using? Still can't believe the 50-60 hp diference. Something doesn't make sense.

 

[Louie L.]

Its all in the converter. Sure tune will help , but the converter is where its at. I can spool my PT70GTQ right now on the brake.

Im also no sure that the New GTQ is totally done at 22-23 psi, but my car sure went fast on that Low of boost.

 

[azgn]

Fuelie600, I'm not gonna argue with you, but I happen to have first hand, real world experience....suggest maybe you try one and see for yourself

 

[Fuelie600]

Woody, I'm not arguing--I'm inquiring. What your saying contradicts all that I was told when researching for a new turbo. Looking to find out why. That all. Same size housings and wheels, and one runs much stronger than the other, I'd like to fiqure out why. If anyone can explain this to me, I'd appreciate it greatly. My understanding is that the GT turbos are more street freindly, and spool a little quicker than non GT's ( ball bearings excluded ), but I was told the power falls off some after 23-25 psi, as opposed to non GT's. It makes no sense to spend $3000 to buy and test both turbos, so I am asking if someone could clear this up for me and anyone else who would like an answer. Thanks, Brian

 

[Fuelie600]

Curiousity has got me. I am going to call John again today. Maybe I didn't understand him the first time.

 

[aquickv6]

According to Limit Engineering, there is no problem in running the 70 GT P trim to 30 psi. The compressor map shows no dip at the mentioned 23 -24 level. It is supposed to make power to 30+psi.

 

[azgn]

Fuelie

There is a reason the fast TSM cars all run GTQ turbos......and most switched from the BB type....that reason is the 50-60 HP you are talking about....the two local cars that did the swap picked up just what I said......

I have never heard any one say the GTQ was "easier" to spool than the non GTQ turbos...once again, my experience and the two local cars found the GTQ difficult to spool...of course their frame of reference is the BB 70......I can say that my Limit 70P trim spools about twice as fast as the GTQ... Now, as compareed to a regular Q trim, I cannot say

if you can spool the GTQ, it is definitely the turbo of choice....many guys seem to have success with converters in the 38-4000 range....I just didn't like the results I got with my Art Carr "N" converter (supposed to be 3800 stall) and the GTQ..I have no doubt it would make more power than my P trim, just not where I needed it