Inliners International Forums General Discussion Blown and Injected MY turbo 4200 project.

Thought some of yall would enjoy this, and hopefully I can get some help at the same time.

Anyways, Im putting together a turbo 4.2L for a'56 chevy truck my Dad is building. Looking to run 8psi in stock form, and eventually pushing up that number to the 14-16 range. Engine will be basically a 100% street motor, but hopefully will run real hard and put some v's to shame. Truck will have a very race oriented suspension with nice sway bars and such, setup for the road track but will probably never see one.

Trans will be built in a 4L60 case, as strong as possible. Im going to stay away from the 80e because of the huge amounts of loss that it brings.

Im keeping the stock ecu and its components. I have efilive and I've been getting my feet wet tuning lsx engines, so Im hoping to be able to tune this engine. The main issue I see so far is using a MAP that can read boost and tuning with it. If I have problems tuning it I will call in a friend who is very, very big in the MS world.

So far I have modded the oil pan, and redone the belt system to delete the p/s pump and a/c.

Im hoping to provide many, many pictures of each one of my mod's to further the info that is known on this engine.

so on to the pics.

drilled and tapped girdle to bolt pick up tube.





stuff that got cut off



cut off



sheeted

























start of baffles


more sheet




layed foil down so incase the weld blew out it wont drop down in the block



getting welded







stretched the pickup





I took off the a/c compressor since the truck wont have a/c. Also dropped p/s pump, since the truck will be manually steered.

After this I needed a new way to tension and another idler pulley so I used a stock vette tensioner and made a bracket...











basic belt layout



that is all for now.

I need to get a dip stick setup and an oil drain plug. Dip stick will come from a Lokar and is one for a ford 351 engine as it has 1/4 npt threads and is suitable for custom application.

I got an exhaust flange, and can get anyone one if they need one. Something like $100 a flange. Will get pics up soon of that.

At first the engine will be stock internals, but eventually the compression will be dropped, and hopefully the head can be ported to flow as good as a ported 06+ head..or maybe drop a ported 06+ head on this motor? not sure if that will line up, need to do some research.

I been trying to size a turbo for the engine...anyone have suggestions or ideas? I think the turbo nova wagon has a 88mm, but thats all I've heard? I also understand the nova is extremely built, so Im looking for mucho help in this department.


Sorry for the long post, appreciate yalls time.

Great pictures. I will be following your project closely. I have an 07 4.2l waiting for me to start, for a 53 chevy car. Will need a rear sump pan etc.
Mike

Nice start on it! Will be following along also. Tom

cajundragger, looks like you're off to a great start. Thanx for posting the great photos.
Mike 53-210, I've mounted my '06 4200 in my '54 Chev sedan delivery so we will have some common issues. I'll start a new thread with photos if you're interested (teh-heh). I don't have a rear sump pan yet as efi-diy is still working on his rendition to be made available for purchase.

thanks guys


Im having issues figuring out the pressure ratio and airflow needed.

for 600 horses Im calculating that I need 66 lb/min with a ratio of 2.75. Then for 800 horse Im calculating 88 lb/min and a ratio of 3.5. But this doesnt really seem right at all.

if that is indeed correct then Im going to need to push ~21 pounds for 600 and ~34 pounds for 800 horses.

this is what Im using for help...
http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html

Douglas' 250 made 700 HP w/7 psi of boost pressure.

There are so many variables,to think about, there is not just one formula.
My 62-1 turbo is good for 625 HP flows up to about 60 lbs per/min
http://www.turbocharged.com/catalog/compmaps/fig10.html

Nice project BTW


MBHD

whos douglas and is his project on the internet?

Here is an old thread
https://www.inliners.org/ubbthreads/ubbthreads.php?ubb=showflat&Number=51793&fpart=1

Here is the faSTEST CAR IN HIS CLASS THAT SET A NEW RECORD OF 7.8 SECS

http://www.youtube.com/watch?v=jBMHJ-O4lTU

You might be interested in a turbo manifold.. http://steedspeed.com/chevy_trailblazer_4200_vortec_turbo_manifold

He has one in stock right now - ignore the no stock on the web page. Leen's to busy making manifolds to update the web page very often.

I am interested in that manifold but the price tag scares me away when I can just build something to work. Not to mention I like to weld and stuff. Plans are right now to do use a split flange T4 compressor housing with the header being equal length runners combining cylinders 1,2,3 and cylinders 4,5,6.

Right now Im leaning towards a GT4088R with a .95A/R. Taking a poll most people who are pushing these 6's and other higher reving yet lower displacement ones (supras) seem to be running this turbo and like it. Plus with my ruff calculations it should work real well and have me right in its most efficient range. The only thing Im worried about is the A/R ratio causing the engine to be a dog down low and having a fast yet very powerful power band.

what do yall think?

nitrous will fix that low end bog

I'm running a GT4088 on my 4200 with a 1.34 AR. The one change i would make if i was to start over is more static CR. Say 9:1 instead of 8.2:1.

Exhaust side head porting is critical to getting this engine to work with the turbo.

I was just looking at that turbo. At $700 cheaper it is much more affordable but I dont like the fact that the A/R is more or less fixed.

do you think the pre 06 head could be ported and clean up as much as a post 06 head?

also what are you running for a wastegate and BOV? Im trying to size those up but the lack of info is aggravating.

EFI-DIY

Does having an A/R of 1.34 cause for a laggy turbo spool-up?

What RPM do you see full boost?

MBHD

Im wondering the same.

I know the ported head will spool it much quicker than my non ported head though.

Full boost is ontap by 3400, I thought about changing the exhaust scroll but I'm thinking the boost will be on all the time.

The early head need a LOT more work to get the head to flow.

My friends 2004 Dodge diesel 1500 gets boost all the time, but that's a diesel.

I would think if you downsize the A/R on the turbine housing you will like the driveability a bit better, but that's just me, I am sure when you are @ full boost you dont give crap about what happpened before 3400.

I would think a .84 A/R would work nicely & get to full boost by around 2800. ,,,Just me thinking out loud,dont mind me.

I am just dreamen when I can feel some boost on my inline6!!!

I get full boost on my Syclone 4.3 by 2400. It's A/R is approx a .63 T3

I have to step into it to show positive boost,it's ( boost pressure ) not all the time, not even close.

MBHD

It seemed not to work that good for Douglas,, 75 HP of nitrous & still could only muster 10 psi.

His A/R 1.45 T6

can you get a different A/R housing for the GT4088 non ball bearing...

pics of my engine mounts I made today...

You got that right .... the truck becomes a handfull to drive.. the 275R60-15's don't have a chance...

Chi-town hustler anyone....

At the track the i have to get the Goodyear drag radials hot.. This year I hope to get the NO2 shot working to get rid of the lag.. Last pass last year I managed to spool enough to launch a 7-8 psi - what a kick in the butt. Can't imagine what 15 will feel like..

75hp isn't much nitrous, except for maybe a small motorcycle. I'm hitting mine with 100 because it's a mild build and I've got the jets. A 175 shot would still be conservative in anything with Douglas' level of cylinder head flow.

As far as I know, most people do not need to run 100 -175 HP nitrous just to spool up a turbo, I could be wrong though

The problem w/Douglas's combo IMO, turbo is too big, A/R of 1.45,T6 sized turbo

Way too much overlap on his camshaft. I forgot his camshaft specs,but believe me it's huge.

He was supposed to email me his cam specs. Still waiting.

MBHD

75hp does seem to spool most turbos. I've just never understood why "turbo guys" are so afraid of nitrous. It spools, it intercools, it slices and dices! But then I was a nitrous guy first, so maybe my perspective is different.