Inliners International Forums General Discussion Blown and Injected Newb Questions

Hi guys, new to the forum but I have been reading for a while. I recently picked up a 65 Chev C10 with a 250 six banger in it built in may of 65 but came with a 250 not a 230 which makes the truck kinda unique. Currently I'm just in the process of getting the out of province inspection done (Canada) but I'm also planning the engine and suspension upgrades. When I go on the truck forums pretty well all of the rigs have the standard SBC auto tranny combo. If I were to go that route I will just do an LS conversion and be done with it but I keep coming back to turboing the original six. As a result I have a couple of questions.

I'd really like to get in the order of 400 crank HP out of my motor so I'm guessing on a purpose built motor I'd need in the order of 10 lbs boost????? I have a spare Garrett GT2554 lying around that I think would handle 5 lbs efficiently after that it's probably way too small. What turbo or turbo size are most guys running?

Looking at the SPA manifolds they seem to be available in both T3 and T4. If I were to buy a T3 manifold I could use my GT2554 with a T25 to T3 adaptor at low boost initially till I got it set up then switch to a different turbo later. Is the T3 flange too limiting for what I am thinking. Using the T3 I could go up to a GT35 I think as the largest turbo. I suppose I could use a T25 T4 adaptor if that manifold is preferable.

My last question is regarding lag. I plan to use the truck as a daily driver so I don't want to constanly be on the boost but on the other hand I want it there pretty much right now when I need it. How does the 250 respond to being boosted?

Probably enough questions for now. Comments?

Thx M5

Ps This won't be my first turbo experience so all the plumbing etc I already understand.

The SPA manifold you can buy from mrhotrod6@bellsouth.net

I have a T3/T4 Turbonetics hybrid turbo 62-1 rated for 600-625 HP,it's old,so maybe Turbonetics makes T3/T4 hybrids good for more power?

T-25 adapter would really choke it.

A GT35 will will great.,IIRC,,they make a 1.something A/R on the turbine housing,thats too large for an everyday driver w/low stall converter. Poor boost responce,laggy.

A turbonetics turbo with following specs approx,
A 60-1 High five Compressor wheel,.70 compressor housing
A T3/T4 turbo will work. .63 A/R on the turbine housing approx stall 2400 RPM)up to .84(that would need a higher stall min 2800)

The 250 will respond well to boost as will most engines,but more so because of poor cyl head design.Siamessed port.

Hope this helps a bit.
Welcome aboard!

MBHD

Probably should have added the truck is going to stay a standard 5 speed.

M5

I would go w/a .63 A/R on the turbine housing. T3 were talking here.


MBHD

Using the T25 will not be my final solution but it could get me started seeing as I already have the turbo which has had the wastegate ported etc and works pretty well. The GT2554 has a 54 mm wheel with a .64A/R. It's a little small but I'm pretty sure it'll handle 5-8 lbs no problem but after that it'll make too much heat and be beyond it's maximum effciency on the compressor map.One thing that I've found with the smaller turbos is they spool instantly. So I guess in answer to my question get the T3 manifold not the T4. I looked on the Turbonetics site and they don't really list their specs that I can see. My experience is with Garrett so I am more familiar with their product line.

M5

You can email mrhotrod6@bellsouth.net & see what manifolds he has right now.

It really does not matter if you want a T3 or a T4 manifold.

Unless you want to make a lot more power than a T3 turbo can offer.

You can convert it latter for a T4 pattern if you would need or want to.


MBHD

I would recomend a T4 Turbo manifold. There are not as many choices for turbine wheel and exh housing sizes for the T3. Many more for a T4.
You will find the turbos will spool very easy on these inline six's, infact over spooling can be a problem.
Here is a site with Turbonetics Turbo Matrix. It is the second choice down.

http://www.treadstoneperformance.com/techinfo.phtml

The chart says 60-1 with a .68 housing

I think a T4 turbonetics 60-1 in P trim exh wheel with a .68-.84 housing will be very close.

Just this spring I dyno tested a 250 with a 60 size turbo and 5 PSI and it responded very well. 400 Hp should not be a problem, even with less than 10 PSI. Tom

I've actually watched most of your videos on Youtube and have been planning on giving you a call at some point. When you work over the heads for a turbo application what all do you do. I don't have any issues with doing the bottom end but I was thinking of getting the head done by someone with some experience in the field. I've done a ton of searching and reading of late and someplace I found something about an intake manifold with the fuel injection bosses already on it. Do you know which one that might be. I'd really prefer to do the project with EFI so I can data log and just use a wideband to help tune. What would be the best choice, Megasquirt?


M5

I have those injection manifolds instock.

As for the head, normal performance work is involved.
Bigger valves and the modifications to make them work right, screw in studs and a nice deck surface to seal it all up. I also prefer to use head studs over bolts. Felpro 1025 head gasket.

I use a Holley system, the MS will work good also. Tom

Tlowe,,,,
Do you mind explaining this comment.

The L6's spool a turbo faster or different than V-8 ,V-10,V-12 ?

Also,if you could, explaine this overspooling problem these six's have. I do not want to have these problems whenever I get my turbo going.

Thank you so much.


MBHD

If you select a turbo that is too small specifically the A/R is too small it can spin up so fast that it basically over revs and goes way off the compressor map. You end up with poor performance, lots and lots of heat and short turbo life. Thats my guess as to what he meant but I could be misunderstanding as well.

M5

If you look @ his post,he says the inlines six's tend to overspin/spool turbochargers.

"You will find the turbos will spool very easy on these inline six's, infact over spooling can be a problem."

I am asking why only six's tend to over spin/spool the turbo?
You could be correct on what he was thinking but I am not so sure,that's why I posted this in hopes for a response from him.
Looks like he ignores some posts & answers other posts.



MBHD

I suspect the answer will come after the holiday weekend.

M5,
You have this exactly right. Most times guy's are trying to use junkyard or backyard DIY turbo setups that are sized wrong and end up with: too much boost, excessive back pressure, short lived turbos and the list goes on. Forgot the emptier wallet.

Just trying to make sure it goes right the first time. Most guys only want 5-10 PSI for street use. This will really wake up a engine. Tom

[/quote]

Ohh,OK,
I thought you were referring to your own overboost/overspooling your backyard DIY New Turbonetics turbo that you had picked out for your application & was not a small junkyard turbocharger.

That clears things up.

Thanks for that.

BTW,what actually did cure your overboost/overspinning turbocharger problem?

MBHD

Ohh,OK,
I thought you were referring to your own overboost/overspooling your backyard DIY New Turbonetics turbo that you had picked out for your application & was not a small junkyard turbocharger.

That clears things up.

Thanks for that.

BTW,what actually did cure your overboost/overspinning turbocharger problem?

MBHD [/quote]



Hank,
Just trying to help this guy from my own learned experience. You are like trying to deal with my teenager.

Do you ever wonder why very little people ever respond to a post you start?

Sometimes I think you are intelligent and other times just wonder?

Wish you would just quit the belittling and picking. You do not see me do that to you except for this post.

BTW putting the right size turbo w/proper sized exh A/R housing sure works better than the wrong one that is too small.
Tom

Thanks for clearing that up Tom,

You are welcome. Are we through with this kind of stuff?

I have read where a turbo spools faster with fewer larger exhaust pulses delivered thna many smaller (i.e. smoother} pulse.s true? or not? never ran one - dont know

I have heard the opposite, but, once again, it's only hearsay.

a turbo spools faster with fewer larger exhaust pulses delivered thna many smaller

X2

Smaller engines ,like 4 cyl have a problems w/turbo spool up.

Thats part of the reason they make dual/devided inlets for the turbine housing.

Rotary engines use the devided turbine inlets also.

MBHD