TA49 vs Precision 6262

[Nigel]

Mr Spool are you reading manifold pressure?

62 is a way better option on a 3.8l. Especially over 22 psi compared to 49/44...way more efficient.

If you are reading manifold pressure you have to subtract atmospheric pressure which is 14.7 psi at sea level and drops as you climb to higher elevations. So I could read 36 psi MAP - atmosphere of 14.7 and get 22 psi "boost" (pressure above atmospheric pressure.

This is a common mistake and explains why some people think the Duramax gets 36 PSI of "boost". You are only getting 22 psi of "boost". To make things worse the GM service manual implies you get 36 psi of boost when they mean 36 psi of manifold pressure (above a vacuumpressure which is 14.7 psi at sea level and drops as you climb to higher elevations. So I could read 36 psi MAP - atmosphere of 14.7 and get 22 psi "boost" (pressure above atmospheric pressure).

He is talking 30+ psig, so 44+ psia, which you are calling manifold pressure.

 

[Nigel]

Hey , Thanks for the reply. I'm leaning towards the 6262 but I need a tranny and converter upgrade , They are still stock

Keith, have you had your car to the track yet? I would stick with what you have till you run it out at the track. Last time I was out at LVD, guy there was running a stock long block with a 49, minor mods with a FAST and tune by Bison. He was running 11.4s@115. Stock converter, intercooler, ... I think he could get more, just needed tuning tweaks. The 44/49 works really well with the stock hardware. Cam, heads, converter, then a 6262 makes sense.

 

[Turbo Keith]

I haven't tracked it yet , Soon tho

 

[Ernie GN]

Turbo Keith.
Still running stock Intercooler?
I may have missed it but I didn’t see it in your signature.
That may be a good option. I know a lot of people say they do not get as much pressure drop with a good after market Intercooler. That were you will see same power on less boost.
But you can ask Bison to make sure.

I’ve have gotten lots of help here from others. I like to help as well when I can

 

[Turbo Keith]

Turbo Keith.
Still running stock Intercooler?
I may have missed it but I didn’t see it in your signature.
That may be a good option. I know a lot of people say they do not get as much pressure drop with a good after market Intercooler. That were you will see same power on less boost.
But you can ask Bison to make sure.

I’ve have gotten lots of help here from others. I like to help as well when I can

I have a GN1 front mount IC

 

[Mr.Spool]

Have you read my posts?the better option between the 2 turbos is not cut and dry.I have looked at just about everything from a gauge standpoint at one time or another but what is more important I have a lot of driving and tuning time on lots of combos I know what they run and what's needed to make them run.

 

[JP112_89]

Ahhh... I see you run methanol...can cover up lots of mistakes.

If you ran race fuel with that 58mm up near 30 PSI... You will see that compressor it's not very efficient... I'll see if I can find some logs vs 61,62mm comparing iats in the upper 20s#...without meth masking it.

 

[Mr.Spool]

Ahhh... I see you run methanol...can cover up lots of mistakes.

If you ran race fuel with that 58mm up near 30 PSI... You will see that compressor it's not very efficient... I'll see if I can find some logs vs 61,62mm comparing egts in the upper 20s#...without meth masking it.

Masking?really I have run both race gas and meth and have egts off everything.i have also put a 49 into the 10s.you can talk comp maps and efficiency as much as you want but the reality is once the turbo goes on the car and ran you will not see a gain if you even see a gain before you blow the heads off the car, over the 49 until the boost is way up there (30psi+).the heads suck and the cam peaks early and is done below 5000.you need a converter tight enough to keep the Rpms in the sweet spot on a very narrow rpm range and it gets super tricky the bigger turbos to spool.

 

[JP112_89]

Nice....you put 49 turbo in the 10's with just race gas only, no meth? What were your iats?

 

[JP112_89]

What are your iats without meth running a 49mm at 3.0+ pressure ratio? Just race gas I meant? No meth

 

[Mr.Spool]

Nice....you put 49 turbo in the 10's with just race gas only, no meth? What were your iats?

No I was running twin 10s with 42 lb injectors and a front mount,stock shortblock including cam with a stock ported head.turbo had nothing left.in cold air it would make 30psi with 26 degrees of timing.i would have to look at logs to find exact egts but 1350ish sounds about right I never ran it very high on the egts once I saw no power gains I actually remember lowering them and going faster.2 of my friends cars back in the day ran solely c16 and ran a best of 11.09 with a stock location no egts on those cars.

 

[Mr.Spool]

What are your iats without meth running a 49mm at 3.0+ pressure ratio? Just race gas I meant? No meth

I will put it to you this way i have run 30+psi on a few different combos with stockish stuff with 49 turbos on stock intercooler,stretch intercooler,front mount.the better the intercooler the more iats are controller if you have less intercooler better cool that charge with the proper amount of meth.but what is most important is what kind of racing are you doing.tunes can be made a lot hotter for the 1/8 vs the 1/4.and if your doing hits on the street where cooling down isn't an option the intercooler design should be more of a priority.

 

[JP112_89]

I understand how meth works . I'm just saying you're spraying a whole bunch of methanol to cover up the fact the wheel is too small. Running that wheel with a pressure ratio that ...high out of its range is asking for trouble if the alky didn't spray for some reason.

I'm just saying 62 wheel is a lot safer than a 58 wheel at those high boost levels on 3.8 liter 231 ci.

 

[JP112_89]

I understand how meth works . I'm just saying you're spraying a whole bunch of methanol to cover up the fact the wheel is too small. Running that wheel with a pressure ratio that ...high out of its range is asking for trouble if the alky didn't spray for some reason.

I'm just saying 62 wheel is a lot safer than a 58 wheel at those high boost levels on 3.8 liter 231 ci.

 

[bison]

I understand how meth works . I'm just saying you're spraying a whole bunch of methanol to cover up the fact the wheel is too small. Running that wheel with a pressure ratio that ...high out of its range is asking for trouble if the alky didn't spray for some reason.

I'm just saying 62 wheel is a lot safer than a 58 wheel at those high boost levels on 3.8 liter 231 ci.

It’s not safer. It’s all in fuel system and tune. I’ve seen more engine damage by people using turbos that support less than 80% of their engines needs and running away past the 1000’ than those running smaller turbos.


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[Turbo Keith]

So I guess my question is would I see any gains if I went to a 6262 ? You can see all my upgrades in my Sig , Thanks Keith

 

[SpeedRacerX]

So I guess my question is would I see any gains if I went to a 6262 ? You can see all my upgrades in my Sig , Thanks Keith

Let me see if I can take a shot summing this up...

The TA49 with your mods and all else equal is going to run better than switching to a 6262 except if you are able to "safely" run about 30# of boost then you may see a gain in the quarter but probably not in the 8th.

If you match a torque converter to the 6262 then the 6262 will begin to shine.

If you further do heads and cam, the 6262 will fly.

I'm sure someone will correct me.

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[Turbo Keith]

So I guess my question is would I see any gains if I went to a 6262 ? You can see all my upgrades in my Sig , Thanks Keith

Let me see if I can take a shot summing this up...

The TA49 with your mods and all else equal is going to run better than switching to a 6262 except if you are able to "safely" run about 30# of boost then you may see a gain in the quarter but probably not in the 8th.

If you match a torque converter to the 6262 then the 6262 will begin to shine.

If you further do heads and cam, the 6262 will fly.

I'm sure someone will correct me.

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Thank you Speed Racer , I can understand that

 

[deezdad]

So I guess my question is would I see any gains if I went to a 6262 ? You can see all my upgrades in my Sig , Thanks Keith

Thank you Speed Racer , I can understand that

Not qualified to add anything technical to this discussion but just curious.. what is it about running 26-27 lbs boost w/ a 49 that isn't doing it for you? If you've never been to a track how often do you actually see those numbers... Does your car hook in street trim? Grown men have pooped their pants running that boost on the street

 

[Turbo Keith]

Not qualified to add anything technical to this discussion but just curious.. what is it about running 26-27 lbs boost w/ a 49 that isn't doing it for you? If you've never been to a track how often do you actually see those numbers... Does your car hook in street trim? Grown men have pooped their pants running that boost on the street

LOL , I have tracked it a very few times , and before I go back I wanna make sure I'm getting all I can out of my stock block . I'm hoping low 11s and low 7s in the 1/8 th . But yea bout 30 LBS of Boost will get your attention