99blancoSS

iTrader: (115)

I've used the calculator and searched many a thread but I'm still having trouble. I have prc 5.3 ltr heads and near as I can figure and from their website my scr is 10.75.1. I used oem gaskets. My cam is a tr224 intake is 224.1 exh is 224.9 @.050 Lift is int .561 exh .561 LSA 112.6.
I used the calulator but it comes up with a n/a for my dcr. Having detonation issues I think. Just trying to check bases. We get crappy gas in Oregon but I use premium all the time. Car was tuned in February but it doesnt like the hot weather now. I know timing was retarded quite a bit. Waiting to get to the tuner so we can log and see whats up.

MSGHUFF

iTrader: (7)

Assuming the following and using an old cam card for tr224/112

61cc heads
stock MLS gaskets
pistons .007 out
intake centerline of 108
dur@.006 275

SCR: 10.77
DCR: 8.53

You need to know chamber volume for your heads dur@ .006 and intake centerline but this should be damn close if my assumptions are right

99blancoSS

iTrader: (115)

So my issues could be not enough octane or bad gas maybe? I think the timing is like 18 already

JakeFusion

iTrader: (7)

I don't know where 10.75:1 SCR comes from. That's assuming the piston is in the hole .008", not out of the hole .008".

Anyway, I get this if it has 4 degrees of advance ground in:

Static Compression Ratio 11.15:1
Dynamic Compresion Ratio 8.81:1

Try retarding the cam 2 degrees. Will put DCR back down to 8.67:1. 8.81 is too much for 92 octane and heat, unless you have an aluminum radiator with an oil cooler and a much better quench than .045".

jrp

iTrader: (16)

i used a 62cc chamber, stock MLS, and the .006, lsa, and icl from a TR224 cam card and i come up with

SCR 10.8946762990027
DCR 8.46230723434418

99blancoSS

iTrader: (115)

It does have 4 degrees advance. I dont have an adj timing set either. CRAP!! Whats the best thing to do here. The tuner said that if I'm getting detonation and it causing kr and I'm still hearing it them theres an issue . He said when it goes into low octane table its at like 15 degrees of timing. What are my best options ? New cam with my heads in mind? or just get a timing set and split cover? Or use race gas ? All help appreciated here.

ringram

You will want 93 fuel MIN IMHO.
Run a cooler T'Stat set up your fans for it and check your plugs you might want to drop a range cooler.

99blancoSS

iTrader: (115)

Already running the tr6's. Is there anyway to be certain of the my scr and dcr?

MSGHUFF

iTrader: (7)

yes provide the info I asked for in the first post. Head cc, dur @ .006, intake valve centerline. Your SCR and DCR are fine and well within the optimum range I would bet the numbers I posted are extremly close. I would take a look at some other area's. Are you are sucking oil through your intake? Crappy gas/clogged fuel filter? carbon build-up? From what you described in your earlier posts the car ran great then progressively got worse so I doubt it would be an issue with your setup. You should check the basics then find someone to do some data logging and pinpoint the problem.

99blancoSS

iTrader: (115)

Well I have to wait for TSP to get the head numbers. The big thing here is it doesnt like the heat. Its a whole lot worse if I try to run the ac. Been a while for the fuel filter I guess, I'll change that as well. I've changed to a different gas station but we just have crappy gas in Oregon no matter where I go. This is very frustrating.

99blancoSS

iTrader: (115)

If I were to buy race gas what octane should I go with? Using a mix a good idea?

Beast96Z

iTrader: (21)

It's looking like your DCR is too high. I came up with 8.7 myself. That, associated with heat, and crappy gas will more than likley give you your problems. I would try and find some 100 octane unleaded at the pump somewhere. We have it here, but I'm not sure about up there. Worst comes to worst, mix in a quality octane booster and see if it helps. Start with the cheap and obvious first. I'm betting a octane boost will fix it.

99blancoSS

iTrader: (115)

Would an exhaust leak effect detontation? I just discovered the egr tube on the header has a broken weld.

Beast96Z

iTrader: (21)

It may cause false knock, but something that small won't actually make the car detonate.

99blancoSS

iTrader: (115)

If in fact my dcr is to high what are all the options I have?

The Alchemist

iTrader: (19)

I have nearly the same setup and don't have the KR issues, even in the summer heat. Check your intake to see if you're sucking in oil. That will lower your octane rating dramatically, from 93 down to as far as below 87 depending on how much you're sucking in.

Go to a tighter head gasket to decrease the quench, and you may actually reduce your tendency to knock as well. I plan on doing that myself in the next few weeks.

99blancoSS

iTrader: (115)

I've got a catch can, so that should eliminate the oil in intake issue. I changed the fuel filter and thermostat yesterday and discovered a broken egr tube on the passenger side header. Talked to my tuner and he was very suprised at my results. He had a car with about 40 less hp than me(on his dyno) go 11.90 at the track so he knows something is up. I need to get the header fixed before we can do anything though.

Beast96Z

iTrader: (21)

Like I said, start with the obvious. If it is a compression thing, the added octane should clear it up. If it is compression, either new heads with bigger chambers, thinner gaskets, a new cam, or adjustable timing set may be in order. I would say the mixture of high DCR with a bad quench area may be causing the problem.