Twins- am i expecting too much?

1977IHLoadstar

1977IHLoadstar

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Nov 4, 2011
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Info on setup- HE351VE manifold charger with adjustable stop for minimum housing size set around 10cm2 (as far as i can calculate) and a spring to hold it closed untill drive pressure opens it up. Big charger is an HT60 with 22cm2 housing. Factory exhaust manifold, 2nd gen intercooler, 3.5" charge piping, 3.5" "intake horn" into factory intake manifold and 5" exhaust from trubo back.
For fuel I am running a 160 ppump (not racked or anything) with Big Blues 024+ dvs, no fuel plate, heavy spring in AFC so it hits full travel at 50psi, washer 3k gsk, and fed 30psi by a walbro 255pump. I am using Industial Injection 100hp injectors.
I think that about wraps it up for parts.
My question pertains to EGTs and smoke. At WOT this setup makes around 65PSI in the manifold, 30PSI from the HT60, and has about 80PSI drive pressure and will creep above 1400EGT (afc full back) and 1600EGT (afc full forward) . I expected that the smallish injectors (at least from what i can gather, hard to compare since they are rated at 62LPM and everyone else goes by orifice size) would be a limiting factor and keep things cool and clean with the twins. Do my numbers seem out of line? I was hoping to not have any temp issues by sticking with smaller injectors. Could i be flow limited by my factory exhaust manifold? Are the injectors bigger than i thought? Am i doing something wrong that i dont realize?
I guess at this point my options are to pull fuel- less fun, or add air-more fun.
On the bright side it does pull hard!
Suggestions?
Sorry for being long, just trying to be thorough

Pic for reference

DSC_0219_zps8c083fd7.jpg
 
That thing looks AWESOME! Do you have a build thread or anymore pictures?
 
I would run the secondary harder. If I run my he351 at low boost, egts get hot.
 
Thanks for the input everyone.
Is 1400* reasonable, or am i pushing my luck?
I wouldnt mind going to 20* on the timing but am nervous for the head gasket, running SHCS torqued to 130lbs. This truck was meant to be around 300hp this year and was prepped for that but seems to have gotten a little out of hand, lol. I guess i wil need to think about.
Hoping to build a head this year to install next winter, along with proper studs.

There is no build thread, actually this is the only engine picture i have- when i go into the garage i do work and forget the camera!


RyanH said:
I would run the secondary harder. If I run my he351 at low boost, egts get hot.
Click to expand...

I wasnt sure if my drive pressure was a little high already, i know i cant count on 1:1 but would like to see it close. From my understanding driving the secondary harder (not letting it open as much) would raise drive pressure even more. Am i wrong?
 
No your right, sorry I should have specified try running secondary harder and primary a lil less to compensate. Basically just play with the waste gates.
On my compounds, the slightest WG adjustment can change egts and boost/dp dramatically.
 
You can get more air by driving primary harder..
As that its technically your air into the engine..
Now, add timing first to around 20 then play with secondary gate adjustment..
And 1400 isn't going to hurt anything..unless you are towing at that.. Also your head bolts will hold a lot more than you are throwing at it..
 
I guess i should specify, i am not running a gate on the primary- i was intending for lack of fuel to be the limiting factor on total boost.
I wont tow WOT so that shouldnt be an issue for that.
I hope that you are right about the head bolts as i may give it some more timing- the power is admittedly addictive. I hope i can keep the power and tune out some heat, but never really thought of advancing timing to do that.

Thanks for the advice all.
 
Big blue made 780jp on stock head gasket and bolts.
I am making somewhere over 600 at 75lbs of boost on shcp's
If you let your secondary open easier, drive will drop, boost will drop, primary boost will increase. Will rev a bit more freely.. And should drop egts as well.
 
I have a similar setup on my 98' HX35 over HT60 with 20cm housing. I see 30-32 psi between stages and 65 psi at the intake manifold. My setup runs really clean but hot, 1700* by the end of the 1/4 mile.

5x.016" VCO injectors, 052" delivery valve (about 25 cc's less than your dv's), 180 pump with 4ks and timing is right at 18*.
 
Does anyone know what II 100hp injectors compare to? They are rated at 62LPM (as far as i remember) and are an 8 hole injector. I thought they were slightly smaller than 5x12 but have the feeling i was wrong about that. Or maybe the DVs are causing me to be over fuelled?
Just trying to wrap my head around exactly what is going on since its only a 160pump

Headcase- yes that is my truck from a few years ago, but now it is crewcab and no longer powered by a 7.3 IDI, quite happy with both changes!
 
From the info you have posted, it seems like you've got it pretty well tuned, just bump the timing 2-4 degrees. You could use some more primary air, but you'd need a smaller housing.

I ran the bolts for a while @ 135lbs. Did many passes @ 90psi, 20-22 degrees. 1 pass @ 26 degrees.
 
I heard something about the He351ve not flowing very well. Maybe you could swap in a standard He351cw and see if that helps.
 
I really don't see much of an issue with 1400* or 1600*. But 16* of timing is pretty low. And from everything I've gathered, 12v's tend to like 5 hole injectors more than 8 holes. But it's been a long time since I studied 12v's.
 
62lpm is a decent-sized injector. I'd say you're on the right track, just turn it down a tad, bump the timing, and get an o-ringed or fire-ringed head ready. My 89 held 50psi plus nitrous on bolts, and my 95 blew a head gasket at 35psi on the stock turbo (and 230rwhp) so it's kind of the luck of the draw from the factory.
 
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