Prochraged LT4 Going to the Dyno... any bets
10-11-2018, 09:46 AM
#21
Team Owner
Pro Mechanic
You're probably right, and definitely right about any detonation. I honestly have no experience with FI, 450+ hp combos on stock bottom ends...so OP should listen to Surf'nsun.
10-11-2018, 10:36 AM
#22
Drifting
Thread Starter
They dyno shop is a tuning shop as well. What I am paying for is 2 pulls on the dyno and a recommendations on how to improve.
This car is never raced. Heck, the Avg MPG in the car shows over 23.5. That should give you an idea of how it gets driven.
Last edited by KyleF; 10-11-2018 at 10:43 AM.
10-12-2018, 09:54 AM
#25
Drifting
Thread Starter
10-12-2018, 12:27 PM
#27
Drifting
Thread Starter
10-12-2018, 01:30 PM
#28
it won't last forever, but it sure is fun for now.
10-22-2018, 11:32 AM
#30
Drifting
Thread Starter
So... after posting this and some of the responses... I started digging. Like I said originally, I have not had the car very long and have had an IROC project setting right next to it that has been getting my time. The Corvette is turn key ready to drive as it sits, and the IROC had some issues I am working through.
The car came with a stack of documents, receipts, service records, window sticker, etc. Just hadn't had a reason to dig thought it since I knew the belt tensioner needed replaced, but all fluids were good, tires were good, no codes, and everything worked. Well except the dang noisy bearing in the tensioner pulley. While I was in there, I just replaced the belt for good measure.
So in the paperwork I found the receipt for the install and... tune! So I now know it has a tune. Then even better, I found notes on the tune. The notes included it's an LT1 kit with a target of 12:1 WOT A/F ratio, but noted LT4 being higher compression and target shifted to 11.6:1. Rev limiter set to initial HP fall off of 5800 RPM.... then it noted Max boost to be 8PSI! Hmmm... So I went out and drove the car late one night in a nice open area in the country. From a roll 1st-2nd-3rd... and was actually able to watch the boost gage. Peak 12 in 1st gear then falls off some, let off, shift, Peak 10PSI in 2nd and then falling off to 8-9PSI and in third same as second. Strange... but explains why I was seeing 12PSI. So, I got an old gage I had laying around from a diesel truck I once had and taped in to the windshield and ran the tube to the connector to the FPR. Did a retest, and BAM... solid 8PSI at WOT up to the rev limiter at what appeared to be 5900/6000RPM on the dash tachometer.
Appears there is something off with my gage.
There was a dyno chart in the file too. Wish the guy I bought it off of would have mentioned that... not even sure he knew since he bought it with the kit installed and maybe didn't look for it since all he did was car shows and cruises. The chart shows the graph, but no peak numbers for HP or Torque listed.
So the game is still on, but I feel a lot better about where the car is now.
The car came with a stack of documents, receipts, service records, window sticker, etc. Just hadn't had a reason to dig thought it since I knew the belt tensioner needed replaced, but all fluids were good, tires were good, no codes, and everything worked. Well except the dang noisy bearing in the tensioner pulley. While I was in there, I just replaced the belt for good measure.
So in the paperwork I found the receipt for the install and... tune! So I now know it has a tune. Then even better, I found notes on the tune. The notes included it's an LT1 kit with a target of 12:1 WOT A/F ratio, but noted LT4 being higher compression and target shifted to 11.6:1. Rev limiter set to initial HP fall off of 5800 RPM.... then it noted Max boost to be 8PSI! Hmmm... So I went out and drove the car late one night in a nice open area in the country. From a roll 1st-2nd-3rd... and was actually able to watch the boost gage. Peak 12 in 1st gear then falls off some, let off, shift, Peak 10PSI in 2nd and then falling off to 8-9PSI and in third same as second. Strange... but explains why I was seeing 12PSI. So, I got an old gage I had laying around from a diesel truck I once had and taped in to the windshield and ran the tube to the connector to the FPR. Did a retest, and BAM... solid 8PSI at WOT up to the rev limiter at what appeared to be 5900/6000RPM on the dash tachometer.
Appears there is something off with my gage.
There was a dyno chart in the file too. Wish the guy I bought it off of would have mentioned that... not even sure he knew since he bought it with the kit installed and maybe didn't look for it since all he did was car shows and cruises. The chart shows the graph, but no peak numbers for HP or Torque listed.
So the game is still on, but I feel a lot better about where the car is now.
Last edited by KyleF; 10-22-2018 at 11:34 AM.
10-22-2018, 01:08 PM
#31
Melting Slicks
Well... my guess is 375-385. Sounds like you may have a little belt slip which isn’t uncommon on these setups
edit... forgot to account for the stock compression so closer to 400-410
edit... forgot to account for the stock compression so closer to 400-410
Last edited by qwiketz; 10-22-2018 at 01:09 PM.
10-22-2018, 02:16 PM
#32
Drifting
Thread Starter
10-27-2018, 12:41 PM
#33
Drifting
Thread Starter
Today is the day, waiting in line.
10-27-2018, 01:33 PM
#34
Melting Slicks
I'm at work and waiting......*tap* *tap*
Have fun and good luck!
I'll say 407
Have fun and good luck!
I'll say 407
10-27-2018, 05:18 PM
#36
Drifting
Thread Starter
383.3hp/358.3tq 8PSI
not too bad. In discussion with the guys at the shop, and they are a Procharger shop, they feel the car has a very conservative tune. Suggested ditching the FMU and going to a larger single pump, injectors, cam, and headers to stay safe and get maximum results. They feel getting to 450whp would be doable on stock bottom end if it was done right and then not abused.
Last edited by KyleF; 10-27-2018 at 05:38 PM.
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Benny42 (10-27-2018)
10-27-2018, 05:36 PM
#37
Drifting
Thread Starter
10-27-2018, 09:46 PM
#39
Race Director
What blower model do you have?
That was a mustang dynometer which read low compared to a dynojet (except for low power 4 cylinders for some reason).
im making 520 ish rwhp (dynojet) on my 93 with afr heads, lloyd elliot 224/236 blower cam, meth/water inj , p600b @ 12 psi boost @ 6000 rpm, 1 3/4” headers.
its stock bottom end. No issues bc i tuned it right. Though note i did achieve a lower static conpression (9.7:1 ) by putting on bigger cc heads.
even so, the comments about hurting your stock engine on 12 psi boost are hogwash - unless you have a sh1tty tune, an inadequete fuel system or arent using meth/water inj.
its my belief that these comments were born in the days before meth/water inj and before people knew how to tune. People would trick out a coolant temp sensor with a resistor, for example, to try and get it to add more fuel bc they didnt know how to tune.
people had inadequete fuel systems. Were trying to use stock injectors, stock fuel pumps, and failure prone FMU’s that come with the kits
note that modern oem forced induction systems are higher compression (not the 8:1 like you used to see) and dont even come with forged oem pistons anymore.
the knock sensor is an excellent system that will also save your motor from detonation damage too. So keep that in mind.
Lastly, did they let you drive it on the dyno? My dyno guy always has me drive it on the dyno (in case it blows up).
i prefer driving it on the dyno bc i can start the pull at a low rpm and get down-low torque info. Though i guess if you asked they could prob arrange that also
That was a mustang dynometer which read low compared to a dynojet (except for low power 4 cylinders for some reason).
im making 520 ish rwhp (dynojet) on my 93 with afr heads, lloyd elliot 224/236 blower cam, meth/water inj , p600b @ 12 psi boost @ 6000 rpm, 1 3/4” headers.
its stock bottom end. No issues bc i tuned it right. Though note i did achieve a lower static conpression (9.7:1 ) by putting on bigger cc heads.
even so, the comments about hurting your stock engine on 12 psi boost are hogwash - unless you have a sh1tty tune, an inadequete fuel system or arent using meth/water inj.
its my belief that these comments were born in the days before meth/water inj and before people knew how to tune. People would trick out a coolant temp sensor with a resistor, for example, to try and get it to add more fuel bc they didnt know how to tune.
people had inadequete fuel systems. Were trying to use stock injectors, stock fuel pumps, and failure prone FMU’s that come with the kits
note that modern oem forced induction systems are higher compression (not the 8:1 like you used to see) and dont even come with forged oem pistons anymore.
the knock sensor is an excellent system that will also save your motor from detonation damage too. So keep that in mind.
Lastly, did they let you drive it on the dyno? My dyno guy always has me drive it on the dyno (in case it blows up).
i prefer driving it on the dyno bc i can start the pull at a low rpm and get down-low torque info. Though i guess if you asked they could prob arrange that also
Last edited by dizwiz24; 10-27-2018 at 10:23 PM.
10-28-2018, 08:27 AM
#40
Team Owner
Member Since: Aug 1999
Location: Florida
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St. Jude Donor '10
I don’t see where water injection was mentioned until you brought it up. He’s also not making 12psi.
There is plenty of documentation on this forum to prove high boost plus high compression = short life span.
There is plenty of documentation on this forum to prove high boost plus high compression = short life span.