olddragger

iTrader: (3)

intake charge temperture----sensor mounted in the pettir upper im or the lim.
This is needed.
OD

Charles R. Hill

iTrader: (7)

Have you a way to data-log the MAF sensor readings? Take a look at that curve.

Huey52

iTrader: (2)

Thanks for the confirmation OD (ICT was in the back of my mind).

Rote8

1. Check belt tension.

2. Check the S/C top pulley bolt torque. (Impact wrench?)

3. Check S/C top pulley "spacer" for correct orientation, they only work one way! (mine was backwards after f'ing with it to insulate everything.)

I am not sure mine will "hold" 12 to 14 permanently, as I have no room (or bollos) to find out!
At some point, my foot lifts.

At 3 K rpm, if I floor it, (instant 10PSI) I hit 12 about 4K and hold till 8K. (I think)

Also, make sure all hose connections are pressure tight, not just vacuum tight, I use rubber cement and a tie wrap on vacuum line ends.

PS: I have watched "vacuum" lines swell loose on the dyno.

Moon Assad

Ha ha, funny. Its meds for my dog, antibiotics I think.

olddragger

iTrader: (3)

good ideas Ray And Rote8.
I have a mechanical vac/boost gauge taking reading from the two vacuum lim ports (pigtailed 2 to 1---i dont hear any leaks and dont see any evidence of any leaks (red boost juice is good for that.)?
SC pulley is tight--best I can tell and test--have electric impact gun?
no belt slippage at this time---boost is steady and I dont hear anything?
All connections are zip tied.?
I no longer have w/m nozzle pre s.c. --took it off for the winter and no track season. I just run one nozzle post blower now.

I will check maf readings tonight---thanks Ray --didnt think of that.

I wonder if my lim work reduced boost somehow--but i dont see how that would be?
It was just cleaning up the runners a little and removed the jet air(its sealed well)?

This past w/e I saw a 8 with a Mazsports turbo set up. It was sweet. I didnt know that Scott removed the apv motor and left the apvs open all the time? I do remember when I had the interceptor (before cams flash) that Scott sold me and had a basic tune with it--the car had more "kick ***" feel to it. Cams is much more driveable.
OD

Charles R. Hill

iTrader: (7)

Thx, Denny. If your LIM work resulted in lower manifold boost then you have done a good job and gleaned some benefits from it. You will also have proven that, at least in one context, the LIM is an impediment to airflow. Remember, "boost" is a value associated with resistance to airflow and is only applicable when evaluating certain things. MAF sensor readings are far more accurate and applicable when evaluating a given engine, especially if you have prior logs. Everything in Rote8's list will evidence itself as a drop-off in MAF readings above a certain RPM.

Bastage

iTrader: (1)

Denny, it's still possible to experience steady boost pressure with a slipping belt. I've had it happen. Tighten your SC belt a little bit and see if it changes anything.

You might need a new tensioner pulley.

Charles R. Hill

iTrader: (7)

Yep, as the VE of the blower and engine change throughout their respective RPM ranges the "boost" level in the manifold will also change. The only way to establish a baseline for diagnosis or furthered development would be to have a drive system that is known to have zero-slippage, a relief valve that has 100% sealing, and a good set of data-logs for a given engine with the above parameters being met.

olddragger

iTrader: (3)

ok sounds like a plan
tonight----
1-efi dude run as is and record boost gauge readings
2- tighen belt and repeat run
double check pulley tightness and connections
if my intake work has caused a 2-3 lbs less boost for comparable maf readings ---then daymnnn. That wasnt expected.
OD

Charles R. Hill

iTrader: (7)

.... and it would be deserving of a hearty pat on the back, Sir! BTW, "Happy" Veteran's Day and thank you for your service (IIRC, you were in the Marines).

olddragger

iTrader: (3)

txs Ray---and Sir you have a very good memory!
OD

Charles R. Hill

iTrader: (7)

Not to begrudge other branches but, if I were to serve, I would probably select the Marines for two reasons; 1) The serious discipline, 2) the dress uniform.

I am too clausterphopic for the Navy, not smart enough for the Air Force, and I don't know much about the Army except for what I have heard from Kane. Besides, if America's soil were attacked I would have no hesitation taking up arms against her enemies.

Rote8

Less boost may mean more flow.
More air flow is never a bad thing.

Rote8

OD,

The Pettit Upper intake or the Mazda lower intake are not good positions for the Intake Charge Temperature sensor, mine is on the inter cooler side of the "hump" so the hump hose isolates the engine heat from the sensor, you want charge temp, not engine temp.

I can read the blower and I/C temp with the position on the output of the I/C, and not read the engine temp via the aluminum connection to the short block.

rotarenvy

I can confirm you can have a constant boost reading with a slipping belt.

If you have a mechanical boost gauge it will iron out the boost fluctuations and give a constant pressure. I

have found the DEFI electrical gauges are extremely sensitive and can pick up the slightest boost fluctuations. I compared my electrical DEFI gauge against an autometer mechanical boost gauge and while the defi picks up fluctuations the autometer will be steady.

olddragger

iTrader: (3)

its almost impossible to get a truely accurate intake charge temp anywhere other than the intake ports and at the combustion entry.
i understand what you are saying but when i took laser temps in both those spots it was not much difference. The sensor just really tells me the intercooler is working and the w/m is working!
My intercooler w/pump lost prime one time and it showed right up!

EFI dude small run tonight
belt slippage at 7.1K limited my rpm--maf was 305 at 7.1K and 9lb boost. ambient temp 70F in take temp was 105F, engine temp was 185. Will tighten belt some more and try again.
OD

Macius8

iTrader: (3)

Anyone have the kit instructions saved in a file somewhere? I don't know what I did with mine. Thanks

olddragger

iTrader: (3)

sorry i have hardcopy only

olddragger

iTrader: (3)

well just for fun i looked at my ltft and it was over 9 and up to 15...........WTH never had that problem before.
Maybe it is time for a new maf?
od

california style

http://www.pettitracing.co.uk/customer.html

will get you the instructions to download...... right click and "save as"

olddragger

iTrader: (3)

chasing lft's is not fun
OD

Moon Assad

Denny, do yourself a big favor and hit your top pully HARD with a good air impact. Ask Greg how hard I hit his, I think he was about to freak out, giggle.

Rotr8

iTrader: (2)

yeah because I was the one holding the damn pulley,,,

Rotr8

iTrader: (2)

OK, so I installed my new BDC ported and polished TB yesterday. Some observations.

-The BDC work(visually) is as expected, the polishing is beautiful.

-The TBs lip or edge is radius'd giving it a knife's edge.

-Dont necessarily notice(yet) a difference in throttle responce.

-The car may still be learning how to breath under idle, but with the BDC TB having a larger diamter at the base of the butterfly there is a larger gap around the non axis of the butterfly, is causing a rythmic idle. The TB(both oem and BDC) will sit in a slight opening under idle. The car now pulses as it tries to understand wether or not the TB is actually opening or not. It has to play catch-up with the understanding the vacuum readings its getting. Its a dance between 1200rpms and around 2K rpms. It thinks the TB is shut but the MAF is telling it to add fuel based off the air that is passing under vacuum. Its a very simular sound to a Bridgeport 13B. Im not sure what to make of this until I look at some data, its only at idle, and so far doesnt seem to hurt any performance

-Once under load everything is fine and hunkers down.

-Full boost(full manifold pressure) seems to come on slight quicker in the higher rpm range, maybe only by a couple 100 rpms, but slightly noticeable.

-There is a very high pitched whistle/whirl when coming off throttle under load, pretty neat, nothing that I feel hurts the performance, actually compliments the SC noise alot

I also took some dimensions off the two to compare sizes, the first dimension is the diamter at the opening, the second is the diamter at the depth where the butterfly sits,



PICS-











Data screenshots from Idle, first is with oe TB and second is from the BDC TB,,,
So far I haven't found anything that indicates that this idle is hurting the car, under load and in gear everything is as expected.
Any Thoughts????