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Discussion Starter · #1 ·
So I FINALLY just got done installing my G-head, port and polished, along with my S60 and ported exhaust manifold, also ditched the balance shafts (and plugged the hole!). All new gaskets, seats, etc. Head studs as well.

I fired it up, ran like crap for a few minutes then started to get normalized. Once it did, took it around the block. Light on it at first, then tried getting on the throttle a bit... this is where I found a problem.

It has NO low end. The spool doesnt kick up till about 3500-4000 RPM! My stock Mitsubishi spooled at like 2K near full boost... Even holding the brakes and giving it gas wont let it build ANY boost.

Does this require break-in to the new turbo? Could my timing have gone off from the difference in heads and turbo? Ill check timing and AFR tomorrow, but wanted to extra advice from anybody who might have some ideas.
 

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Nothing wrong with quick spool, you just don't want clipping, unless you want to trade low/mid torque for higher RPM power.

I have quick spool on my stock TII Garrett, I can get 6psi at 1800rpm in 5th gear in my 2.5L.
5th gear can make boost at 1800 rpms with a very large turbo.

Looking for reasons why his turbo doesnt make boost in normal situations.

Something being wrong or a turbine modification (regardless of being new) would explain that.
 

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Discussion Starter · #12 ·
Payette, right next to Ontario Oregon.

Well, it is definitely better... spool times are definitely longer than the stock mitsu, which was expected. Hits about 5psi at 2.8-3K and builds quick from there, but still have a lot to do, like fuel tuning, leak testing, etc.

Thanx for your help, gang!
 

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Discussion Starter · #13 ·
So curious, is that type of lag normal? around 3K before really spooling good? I can hold the break and give it gas and get up to 10psi after a few seconds, too.

Just want to make sure I did this thing right :D
 

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My 50-large hybrid's powerband is around 3k and up. I don't even think about racing from a dig! You need a built auto and a high stall torque converter.
 

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So curious, is that type of lag normal? around 3K before really spooling good? I can hold the break and give it gas and get up to 10psi after a few seconds, too.

Just want to make sure I did this thing right :D
Normally you need a little cam or head work to get them to spool faster. My engine would spool the S60 faster than my brothers van could spool a mitsu, full boost before 3,000. But it had a big valve head. I believe a new S60 needs some break in time too and light weight oil to run right. Are you running a mini van later stall converter? The early stall speeds are lower, the mini has a 3,400-3,600 stall. You should be able after a few seconds to foot brake to 15 PSI.:)
 

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Discussion Starter · #17 ·
I have a decent port job done no my new G-head, no valve work outside of cleaning and lapping though. The cam is the stock 2.5L roller cam. Stock stall converter.

I am also thinking that a new cal might help as I run VERY rich at lower RPMs to start. Full fuel system upgrade is in order for sure... limiting to 10-13psi at the moment due to stock fuel system :(
 

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From the research I've done with compressor & turbine maps, the S60 makes full boost from 3500-6000.

Turbo and Supercharger Maps

The Garrett GT20 & GT22 turbines are very similar to the T3 .48 & .63 A/R turbines respectively, so you can use their turbine maps. Use Estill's spreadsheet at the bottom of the page to help calculate.

Turbocharger Compressor Calculations

A 3500 stall converter would help, but you'd lose fuel economy. If you need more bottom end, try advance the cam timing 4-6 deg. It'll take from the top end a bit, but who cares, that's when the S60 comes to life. How big is your swingvalve & exhaust? Bigger is better for faster spool-up, especially with that ported exhaust manifold!

May 10th is the first "Night Fever" at Firebird. You going to make it?
 

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I have a decent port job done no my new G-head, no valve work outside of cleaning and lapping though. The cam is the stock 2.5L roller cam. Stock stall converter.

I am also thinking that a new cal might help as I run VERY rich at lower RPMs to start. Full fuel system upgrade is in order for sure... limiting to 10-13psi at the moment due to stock fuel system :(

If you read my post, you will find your answer, as I just read some of your posts to confirm my assumptions.

You performance is going to suck because your using a swirl cal with a G head, G heads love lots of timing an swirl heads dont.
 

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Discussion Starter · #20 ·
If you read my post, you will find your answer, as I just read some of your posts to confirm my assumptions.

You performance is going to suck because your using a swirl cal with a G head, G heads love lots of timing an swirl heads dont.
Thats very good to know. I was looking into a FWD-P Stage 5 cal... think that should do the trick?

Also, I am going to do my best to make it to firebird then!!!
 
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