[gtfoxy]

Originally Posted by cmitchell17

Here is a 74mm/.92 A/R:
Attachment 1052738

I can control AFR to whatever I want, unfortunately I can only ramp in a timing advance and then set it to a constant at a certain RPM, not sure why they don't offer that functionality, but I guess its the old school way of controlling timing just by a ramp and a peak like a distributor setup. You can still have it set to calculate with "optimal" but then again it might not be realistic ie.(30+ degrees).

The timing will be a limitation in duplicating his set up.

I didn’t want to say anything until I was more sure, but I generally will ramp up timing hard until you start building boost, or with torque converter flair, then taper it off to either a stable timing or continue to drop slightly as RPM increases.

Look closely on page 3 & you can see a similar strategy. Notice the white timing line & the green MAP reading.

Add: You can also see how much more lean it is in that transient stage & then richness up.

[gtfoxy]

I’d also add, as it relates to fueling & ignition advance, exhaust velocity needs to be very close to Mach (1050 FPS depending upon certain variables) or at least .8-.9, at 15-30* AEVO, perceived from a bank event, to create enough kinetic energy to drive the turbine hard enough to overcome mass lag (mass of air mass & CHRA mass).

As you will also see on pg 3 is turbine side pressure (drive pressure) is lower than manifold pressure. This is considered an over axiom condition as it relates to Nemo’s axiom, or drive pressure vs compressor pressure. In the old day this was 2:1. Today it can reside in the .8-.9:1 range.

Newer turbos, in the last 15yrs, are able to obtain this pressure ratio due to advances in turbine wheel design, but it takes a given mass @ exhaust velocity.

[cmitchell17]

I tried some different turbo combinations (I believe the simulation only looks up a different compressor map when you change the turbo selection). It still thinks your turbine is just way too big for it to spool or either the A/R is way off.

I put it back to the BW-EFR-8374 since it appears to be the closest match to the map on the matchbot thing:


I checked everything else again, and the stuff I don't know if its correct, intake/exhaust port sizing, shouldn't have that much of an effect being turbocharged. It does know you are twin turbo also, but that being said the turbo sizing does look a little big for being twins? but then again I don't know much about FI and turbos?

[parish8]

I am not sure what you are trying to do. The 8474 is the closest match to what I am actually running.

[cmitchell17]

Originally Posted by parish8

I am not sure what you are trying to do. The 8474 is the closest match to what I am actually running.

Problem is I don't have a compressor map for the 8474 only for the 8374, although they look pretty similar.

My main goal is to try to replicate real builds. I am still pretty low on trying to recreate a stock LT1 and I can't figure out why. I want to eventually use it to size a stroker build to find the best cam. I wish I could calculate and build a simulation myself with matlab, but I'm not good enough to do that, so I am hoping to use this program to match the best cam and possibly turbo sizing for my next build.

[parish8]

I see, sounds like fun if you can sort it out. Kinda like the turbo match bot. I can play with that for hours. I wish there were more compressor maps out there.

[parish8]

I am about to let the magic out of this perfect running 5.3. 😱

[Choda]

oh hell yeah. This is the way.

I like your chain setup on lifting the engine. I bought the motion raceworks lift plate but would rather install the valley cover and fuel stuff on my engine stand instead of in the car. Not sure what I'm going to do when I put mine back in.

[parish8]

Just for fun I measured one ring gap on this stock 75k mile 5.3. Top was .018 and 2nd was .025.

I am not an engine builder. Just thought someone might be curious.

[gtfoxy]

Originally Posted by parish8

Just for fun I measured one ring gap on this stock 75k mile 5.3. Top was .018 and 2nd was .025.

I am not an engine builder. Just thought someone might be curious.

That’s interesting.

They seem to have opened it up a good amount over the 5.3LS.

Which is a very good thing for people looking to throw some boost at these. I pulled apart 3 5.3 LS’s a year ago that had been on various turbo builds. I found like 6 or 7 broken ring lands between the 1st & 2nd ring spread out over the 3.

[parish8]

the trans has made it to steven rankins for the latest and greatest upgrades. the converter is back at circle d getting some new lock up clutches.

this valve train is a little more tricky than i thought.

1.790 installed spring height without any shims
.635 valve lift
1.000 coil bind
Target of .060 to .080 from coil bind.

1.790-0.635-1.000 = .155 current distance from bind. Shim of .075 to .095 to fall within specs?

well hold on. i was told i need to actually measure coil bind so i did and it is really 1.009 so lets redo that.

1.790-0.635-1.009 = .146 current distance from bind. Shim of .066 to .086 to fall within specs? 2 thick and one thin is about .078 of shims so that is what i used for .068 from measured bind or .077 from stated bind.

whew. i thought i was home free after that, finished up one head and bolted it on. went to measure the pushrod length.

7.950 to 7.960 depending on where i measure with zero preload. lifter says .035 of preload +-.010. there are limited choices in pushrods this long. 8.000 is one option but it falls slightly outside of the +-.010 preload. this is when i notice i didn't get or didn't order the short travel lifters that i thought i did and if i had the preload on those is listed as .035 +-.005. no way to get that with pushrods.

i think with the preload listed on these lifters you may be expected to use adjustable rockers. i am going too call johnson lifters tomorrow and see what they think. i want this motor to rev. they sell a roller tip adjustable lifter but the ratio is 1.82 which pushes my lift to 642. i am not sure about that route but i will find out more tomorrow. i am hoping johnson says .005 outside of the spec is fine and that these lifters will rev to the moon and to just buy the 8.000 pushrods.

[KingLT1]

Custom series 3 pushrods from Manton?

http://mantonpushrods.com/pushrod-info/pushrod-series/

[parish8]

I talked to Johnson. They told me the 2126lsr are reduced travel and have other features that will work fine for what I am doing. Said the st2126lsr lifters are hard to hit the preload just right and that I don’t need them.

Also said the best way to hit the preload is custom pushrods. Didn’t know you could get those but it makes sense.

Also said not to forget to add .012-.015 of preload for block and head expansion. Hmm, I wouldn’t have done that without him telling me to. Looks like I am good to go and that extra preload might push me right into a standard length pushrod.

[KingLT1]

Yep you have to factor in block/head expansion into your preload measurement. The short travel lifters ideally need adjustable rockers. I have also seen guys cut the pedestal mount and use custom shims under the pedestals. Either way there is usually a little variance from one valve to the next especially on heads that have been worked over to the point that you can not use short travel stuff unless you adjust each valve accordingly. I honestly think you would still be fine with a 2110 drop in. They have been used successfully in the Copo stuff that turns 8500rpm.