98TAauto

iTrader: (2)

hey guys... first thing is I do have a freshened up bottom end. ARP rod bolts, new rings, and etc(bascially just a clean up of stock with stock rods and pistons still). Anyway, i had the car tuned for the 224/224 .563 114 cam and the TEA 1.5 heads about 2 years ago... made 399.9hp so not to bad.

anyway, we put a F11 cam in(.595 lift) and today on my first WOT passes the car had a weird sputter or missing feeling at the top of the rpms.. Im not certain at what point, but it felt like the gas was cutting off and on at certain points.. The pass was only a 11.60@117 on a 1.60(nittos).. keep in mind thats my first pass in ages so I wasnt really tryng to break any records.. but anyway one the second pass the sputtering was a little worse so i lifted off.. 1st gear roms felt fine, but at the top of second it starts usually. I have the comp 987's that came with the TEA heads. I dunno what valve float feels like, but its like the car wasnt getting the fuel or just couldnt get up and pull at a certain point in the rpms. It wanted to, but something was cutting it out LMAO if that makes sense...

any ideas?? think the 228/230 .595 114 cam is maybe stressing out those springs up top? The A4's shifting at 6500 also if that matters... or is it more or less maybe a tuning issue? more fuel? less fuel. I know I need to get on wideband so thats coming soon. Just wondering if anyone had this problem before maybe

thanks

JNorris

iTrader: (4)

A few possibilities:

Running out of injector
Fuel delivery problem such as the pump or filter
Valve float

When it was sputtering at the top of each gear was there any smoke coming from the exhaust?


One more possibility....Maybe the mechanic messed it up!
John

98TAauto

iTrader: (2)

we doubled and doubled checked all the specs on everything I dunno if any smoke was coming out.. no one said anything about seeing any smoke(this was at our fbody shootout today). I just wanted to make some virgin passes since I hadnt run in ages lol... the bottom end had about 300 miles on it so everything was more than broke in since it still had most of the stock parts lol.

it isnt a consistent sputter.. seems like its kinda here and there in the upper rpms.

I was wondering about running outta fuel also so im gonna replace the fuel filter anyway since its been a lil while. The car feels like it has plenty power, just breaks up up top

are you still running the same springs on your heads John since we got them around the same time. Im just wondering if the .595 lift wa smaybe to much for those springs since they have some miles and passes on them(not alot, but still some age).

ss rally red

iTrader: (8)

When I first installed my F11 (on a 112) I had used 918's on it and when it was dyno tuned(by Allen at FMS) he thought he noticed some valve float, and it had symptoms simular to what you mentioned. Made great #'s but fell off drastically at 6300-6400. I replaced the 918's with fresh 918's and it will pull great all the way to the 6800 limiter now. At my sig numbers I was at 94 % duty cycle also and since have added 37lb ractronic injectors because I have added spray. So you might want to check that also. Hope this helps some.

98TAauto

iTrader: (2)

thanks for the info... im hoping its a simple fuel issue or valve spring issue. I just didnt know if valve float actaully felt like a missing/sputtering feeling up top... kinda like you are off and on spray lol. I wish i coulda describe it better, but i know it just didnt feel good.

thanks for the info so far also

ss rally red

iTrader: (8)

Actullay you describe it fairly well,when mine was on the dyno it acted like it was on the limiter at 63-6400 even though Allen had it set to 6800. It acted as though it was running out of fuel, but in my case it had to be spring related because I swapped in a new set of 918's and TI retainers that I didn't have before it all was good to go. Good luck to you

98TAauto

iTrader: (2)

sounds like my problem then... it actaully does feel like you are hitting the limiter.. cars picks up and lets out.. picks up and lets out...

the 918's held your f11 just fine I take it then? I may invest in a set of 918's again then... When I talked to TEA before I took the motor out, they said I probablky shoulda replace the springs also.. guess I shoulda listened LOL

thanks a bunch for your help also.. i hope thats my prob

JNorris

iTrader: (4)

Jokes to the side. I believe your problem is valve float. I am going to run my new cam (228/232 .588/.575 112+4 aka G5X1) with my original 987 springs and see how it does. If I need to replace them TEA said since I already have the Ti retainers for Comp. double springs I should go with the Comp. 978 double springs. These springs are about $100 for the set.

John

BrentB@TEA

I think the 2 year old 987 springs are your problem. For a cheap fix you can swap to a 978 sprin. Otherwise change to a gold set.

98TAauto

iTrader: (2)

Brent, thanks for the reply.. i know ya'll said I should try to gold springs. Should listened LMAO.. I probably try the 978's and see how those work since i need to get some new ones anyway

John, lemme know how it goes.. im more than happy with the F11 cam. Great cam all around so you should love that 228/232 also

99ls1guy

iTrader: (5)

while we are talking about swapping springs, how many miles do they last? i put in used springs (3-4k miles) last year with a smaller 222/222 .566/.566 cam. ran this cam for about 6-7k miles. then put in a 225/228 cam .572 lift, and kept these same springs. the car didnt put down good power at all with the smaller cam. and i sometimes get a similiar feeling in the upper rpms. mine is more like the rpms are just hanging and not wrapping out like they should. these springs have a tot lof about 15k miles or so on them. am i due for a new set? btw these are 918's im talking about. im not sure what valve float is supposed to feel like. i also dont know if maybe the rockers werent put back on correctly? any advice?