I am currently building a motor for my car and will be using the 6266 dbb. What cam do you recommend Bison? It's a stock stroke forged internals, custom ported/polished irons that should flow VERY well with a port matched intake. Looking to use a flat tappet cam with roller rockers set at 1.65 with the correct pushrods for flat tappet cam/lifters. 3200 stall fully built trans. Hoping for numbers like yours what do I have to do?
6266 bb anyone,or just me?
- Thread starter earcher1
- Start date
turboc87gn
Darkside in Detroit
- Joined
- Oct 2, 2008
I just bought one too 6266 cea 4"in 2.5 out, Is anyone using an internal wastegate and did you have to port the hole in the housing or use a bigger puck to control the boost?
I would just try ported the whole to about an inch and a 1/8 or so and make sure to radius the inner lip of the hole too. At least that is what I have done and it has worked for me. I am using the std THDP puck with my 6265 and iot works fine.
Id scrap the flat cam idea and get a roller and run stock rockers before i put in a flat cam if $ was a concern. A small hyd roller like a 206/206 or 212/212 preferably with lift around .500 at the valve will work well with stock rockers. Id run .560-.590 lift and a faster ramp if i had the GN1 heads i ran and a valvetrain that could handle it. You need to build an engine to support about 800hp which yours should be able to easily if you want to get the numbers and i did with a 62 unless you want to run the boost into the low 30's. You will need to rethink the valvetrin to do so. Converter selection and gearing will play a big part of extracting the most out of a small compressor like this too. Though not all are necessary heres what i used for 697whp peak:
6265S journal 28-29psi/21* verified
8.95:1 CR
GN1 race ported heads/intake
1.65 T&D rockers
218/218 roller Approx .600 lift
885 lifters
PAC 1203 springs
TH headers
Precision front mount
PTC 9.5"
XFI
With this same combo retuned for each the engine made 592whp@22psi/22* with an old 60-1 on the same day and ran about 140mph trap speeds with a 70GTQ@25-26psi/21* about a month ago. I didnt port the wastegate hole at all on the 6265 and ran a stock style internal gate. This car is brutal on the street. With a higher CR and slightly different cam more could have been squeezed out of the 6265.
87WE4BOOSTED
I NEED MORE BOOST!!
- Joined
- Jul 14, 2008
^ The combo mentioned is the TRUTH as far as a TRUE street car, drive it to the track, run the number and drive it home if everything is up to par. 
GetOwnedVette
Active Member
- Joined
- Jun 13, 2006
This was an excellent read...lot of good info and results here
we4Mateo said:
If the engine is capable if 70lbs/min or more mass flow the 6266 should continue to make more power. I'm only speculating 70lbs/min since I've never seen one flow that much on here. The old 6265 was good to 78lbs/min before the compressor ran out of steam. The 65 turbine had a little left in it. Id expect exactly the same with the 66 turbine since it was compressor limited. I ran a .63 precision ex housing. Running a .85 likely wouldn't help power much either since the compressor ran out before the ex side.
Thanks. I'm starting a build now and I think this is the turbo I'll use, 6266. I like that it seems to be controllable with an internal gate. The 6262 seems to be harder to control internally from what I've read? I'll be posting other questions in other sections before I proceed about other aspects of the build. I'd like to be able to trap around 130mph easily with room to grow if I decide to do more to the car itself.
Think about that for a second. The 6262 and 6265/66 use the same compressor wheels and we will say for this instance the same compressor and both will have a .63 ex housing. How would a larger turbine which will drop the ex pressure make it harder to control the boost? Simply put it cant. It takes a given shaft speed to get a desired PR. Bigger heavier turbine will take more energy to get it going and slightly more to keep it going. The shaft speed has to increase as rpm increases or the mass flow will fall off and usually shows up as boost drop. Unless you mean by control your wanting back pressure help the diaphragm pressure. The 6262 is a mismatch of wheels for anyone looking to get the most out of the compressor wheel. The larger turbine is needed to get the most out of the 62cea compressor anyway. If you want room to grow you may need to run a larger hole and when you want to squeeze it hard you may need to either replace the housing or buy a plate so you can reduce the hole size. If not you will likely have to run a lot of spring pressure which will result in spike on spoolup and drop of as the rpm goes up and the ex pressure increases.
Damn it! Why can't this be easier? Maybe it wouldn't be as fun. I'm planning a stock stroke, billet internal 109 build that I'd like to run high 10's right off the street on alky and pump gas with MT ET Streets. Home ported stock irons with good valves and a mild roller. Trying to keep rpm's down, will lock the converter in third. What turbo would you use if...? I want to keep my 3" downpipe with internal gate (RJC big puck), stock TB and intake with RJC plate but port matched to heads and no EGR tower. 5 disc Vig with true 2800 stall, could be loosened. Will 60lb injectors even support this with alky assuming a well voltage fed single pump through stock fuel lines? Dual nozzle needed yet? Sorry, I have a lot of planning to do, but I'm in no hurry. Maybe I should just stick to beeting around the TE44, it seems to be working really well. TIA
we4Mateo said:
I'd go for the 6266 if I was looking for 10.50 or faster. You will need 25+psi to get the numbers you're looking for. The 6266 will easily cover you to where you want to be and the spoolup will be much better with a 2800 and stock ECM car. You shouldn't need a wastegate bypass hole more than 1". Unless you want to run under 50lbs/min. That's the problem. Guys want to run a turbo that has the potential to flow 78lbs/min(6265/66) and run it at 50lbs/min. You just can't do it easily. I ran the 6265 with as machined wastegate bypass and internal wastegate on a 9:1 engine with a little wastegate tension and it produced about 24-25psi on that engine and roughly 73lbs/min. If you're needing more than a 1.1" hole then you are trying to operate the turbo wayyyy below it mass flow potential. The pressure ratio increase isn't parallel to the shaft speed. The way these things are designed and the covers machined they are taking full advantage of the available ex pressure and take less pressure to drive them than older designs.
wickedtt said:
If it was applied properly they wouldnt have these issues. 6265/66 on a mild engine with small cam and cleaned up stock heads will require 3:1 PR to get up around 80% of the potential of the compressor. A lot of guys try and run these at 20psi. Not going to be easy. You will spend a lot of $ on large wastegates and down time as well as possibly hurt the engine trying to run 93/alky and having boost spikes in the 30's
87WE4BOOSTED
I NEED MORE BOOST!!
- Joined
- Jul 14, 2008
IMHO, I would run the 6262 or 6265 (depending on which cam you use) with the wastegate hole ported since you're using the internal gate. One of these turbos should spool just fine with with the converter you have and cover your goals. The 60lb injectors and the alky on stock lines w/one GOOD pump will support mid 10's. Dual nozzle when you're going faster than 10.5 or when your data tells you that you need to upgrade. My combo and tune will allow me to run high 10's right off the street on alky and pump gas. No trailer needed!!
Are you saying that running a 6265/66 at 20 lbs is a bad idea?
I'm still looking at a 6262 but friends have a 6265 and love them (am I correct that the 6266 has replaced the 6265?) but I'm running a THDP and plan on no more than 24 lbs with 93 /alky on the street. Does your above comment also apply to a 6262 at 20-24 lbs?
It depends on the engine. The manifold pressure doesnt really matter. The mass flow does. Youre not going to get to far with a small hyd cam and 20 psi even with the best heads out there. 6265/66 to me means 10.50 or faster. Its totally possible to hit 10.50 with one at 22psi but not easily on a iron heads and small off the shelf hyd cam combo with 93/alky. The 6262 will hit choke flow on the ex side before the compressor is done but is a better choice for just about everyone on here especially if they have a stock bottom end because it will spool faster. Until you get up to a certain mass flow there is no benefit to the larger turbine. Trying to run a 6265/66 at 20psi on a 231ci engine will require a lot of wastegate. I just dont see the point in that.
NyBlankets
Active Member
- Joined
- Mar 17, 2003
@ Bison
How much more would the 6262 have to spin compared to the 6266 to create 25lb of boost and would it generate a measurable increase in heat?
How much more would the 6262 have to spin compared to the 6266 to create 25lb of boost and would it generate a measurable increase in heat?
It depends on the mass flow of the engine. 25psi on your engine compared to 25psi on mine is likely not the same. The more efficient engine will see much higher shaft speeds to make the same boost. Higher shaft speeds doesnt necessarily mean more heat and could actually be less heat if the compressor was run in surge at low shaft speeds . The Pressure ratio relative to shaft speed will be fairly constant at the same shaft speed if you were to switch turbos from a 6262 to a 6265/66 on the same engine. The 62 turbine will have the back pressure rise at a lower mass flow compared to the 65 or 66 ex. The 62 cea doesnt start making a bunch of heat till you try and run it over about 78lbs/min. Thats enough to run 9's. Going up in boost beyond that decreased mass flow and power dropped. The charge air temp rapidly increased. That point was reached on my 9:1 engine with an aggressive hyd roller and race ported GN1 heads around 28-29psi/5500 rpm. For an iron headed less cammed engine it would take a lot more boost to reach the same mass flow. The heat introduced into the air isnt any different than any other turbo that is run in the typical normal efficiency range. so 70-75% efficiency and about 13-14*per psi at the compressor outlet. In all instances when i tested turbos they rarely made excessive heat until i was running them way harder than anyone on here runs them. Most just stopped making boost running the wastegate closed even though the compressor wasnt making excessive heat.
I don't have a problem running more than 20psi all the time! I don't like to turn the boost up just for the track; especially on a alky tune. When it's right, I try to leave it alone. The Extender chip works great for changing boost levels though as it basically self adjusts for the extra flow, if there is any
. I'll run 30+psi sometime though, with a little race gas in the mix.IMHO, I would run the 6262 or 6265 (depending on which cam you use) with the wastegate hole ported since you're using the internal gate. One of these turbos should spool just fine with with the converter you have and cover your goals. The 60lb injectors and the alky on stock lines w/one GOOD pump will support mid 10's. Dual nozzle when you're going faster than 10.5 or when your data tells you that you need to upgrade. My combo and tune will allow me to run high 10's right off the street on alky and pump gas. No trailer needed!!
Thanks for the info on the injectors and alky. I'm trying to stay single nozzle as it's easier to tune. I do change my fuel pump every 3-4 years regardless if it needs it or not and I'll do another new one before the new motor goes in. My block and heads are getting magged and checked over next week. I have steel caps and am now starting to plan the rotating assembly. That'll depend on how the block checks out but it's supposed to be std/std and the bores have good visible factory appearing cross hatching, so hopefully it's all good. I'm doing all good internals from crank to pistons and two steel center caps and no girdle, stock stroke. Hopefully it's a good mate to a 6266SP, and with the ported housing, I can finally ditch my tornado!
Thanks again for everyone who contributed to this thread. It's a good one and has helped me a lot.
