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if you told a&A this was a high altitude car you are going to be sent a smaller pulley to make up for the loss of psi at our altitude. Look at posts by tommypenguin he was a CO vette owner who has a ported head lumpy cam, and fast intake car for an idea of where you will be. Second with your h/c set up you will lose psi but it won’t come with a power loss. Remember boost is a measurement against restriction. If your set up flows better than stock then there will not be as much of bottle neck resulting in less psi.
Things you will need to consider, bigger fuel system to handle the power, pin the factory crank, thicker radiator. That should cover you, I think you will sit around 575 hp with 8 psi
I'm not going to mention the shop at this point, just don't want to go down that road right now. That being said, I'm trailering the Corvette "out east" on Saturday and it will stay out east most of the time (I bought property in a state that has no emissions testing and the Corvette will call this home, it will not pass emissions in Boulder County where I live). I know the crank will be pinned and a Boost-a-pump will be used..... when I drop the car off a week from today, I will inquire about the radiator and any other things I should consider. Thanks for the info!!!
And 575 sounds good to me.... I’d be happy with 550 to be honest, I originally wanted 460-470 and to stay na but I was going to spend way too much just to get 30-35hp over what I have now. So I decided to bump my budget up to where I will not be disappointed in the power. Now I just want to make sure I make the rest of the vehicle last as long as possible before having to put more into it (because I know that’s inevitable at some point). New shocks, brakes, twin disc clutch and supercharger ...... it all starts in a week!!!!
I'm not going to mention the shop at this point, just don't want to go down that road right now. That being said, I'm trailering the Corvette "out east" on Saturday and it will stay out east most of the time (I bought property in a state that has no emissions testing and the Corvette will call this home, it will not pass emissions in Boulder County where I live). I know the crank will be pinned and a Boost-a-pump will be used..... when I drop the car off a week from today, I will inquire about the radiator and any other things I should consider. Thanks for the info!!!
No pressure was more for curiosity sake. I would love to check it out after it’s all done! I think with all the advice in this thread you will be very happy!
No pressure was more for curiosity sake. I would love to check it out after it’s all done! I think with all the advice in this thread you will be very happy!
The work will take a couple weeks so it should be ready to be picked up mid to late November. I’m hoping for a warm spell so I can fly there and drive it back to Colorado so I can break in the clutch over the winter during warm spells and then get a taste of the new power before driving it back in the spring to get on the dyno and make any adjustments or additions at that time. If I don’t get the good weather I have a climate controlled storage facility where it’ll stay until spring.....I’ll let you know how this progresses!
shop called me yesterday and sent me info on the results of my build. 584rwhp/473tq. I got a video of the dyno but haven’t been able to figure out how to download it. Here’s a couple pics I snapped from the video. Well they don’t seem to be loading either. I’ll post when I can figure it out.
The Vette is a thousand miles away and is going into climate controlled storage until April, and it’s going to be hard to wait 4 months......
That's going to be a lot of fun! At the power level you may want to consider changing the gears to 3.90's so it gets into boost a bit faster. Made a huge difference when I had my centri
That's going to be a lot of fun! At the power level you may want to consider changing the gears to 3.90's so it gets into boost a bit faster. Made a huge difference when I had my centri
Maybe in the future but I'll have to get used to the new setup for a while first.
Originally Posted by Time for a C-5
Congrats. Should be fun to drive. Which pulley and how much boost?
Not sure, basic A&A kit (S trim) so whatever pully that comes with. I didn't ask about the boost but guessing its pretty low (5-6 psi).
I have an update, I asked my tuner which pulley and what boost it made. He told me boost was 9-10psi and we are using the 4" pulley. Boost level sounds high to me, but what do I know (very little about this stuff at this point). My RWHP looks great, right what I was hoping (almost 600 but not quite). The RWTQ seems a little low but I'm not worried about it. The AFR I don't know much about but looks to be in the safe range. Tuner also told me he didn't put much timing in it to keep it safe.
I'm dying to drive it but it's going to be 4 months so all I can do is watch the dyno video (I'll post up now that I finally figured out how to download it) and dream about what it's going to feel like.
Finally was able to make the trip to pickup the car since winter is over (although we are supposed to get snow the next couple days up here in the Rockies). I flew to the midwest where I had the work done and stored the car over the winter. With the new clutch I’ve been driving like a gramma.... but did a few 4th gear pulls on the way back to Colorado and felt some decent passing power but nothing crazy.
Upon returning to my high elevation curvy roads, the new shocks make the car feel great but when I ran some 3rd and 4th gear pulls to redline to test the feeling of boost I have to say I’m quite underwhelmed at this point with the added power. So the tuner set rev limiter around 6250rpms and tuned it very conservative to keep it safe (along with 4” pulley) and it was tuned at less than 1000 ft elevation (compared to my 8500 ft elevation) so I’m seeing less boost (6PSI in the hills and 7PSI in the flats @ 5400 ft elevation). Temps were 50-60 degrees so I’m dreading summer temps & what that’ll do ;(
Fuel pressure is good and it is making boost but like I said the most I could get was 7 max and that’s pretty close to rev limiter. I guess I was expecting a massive difference and I honestly can’t really tell much of a difference. To be fair I have not really driven it (rowing gears) because I want to properly break in the clutch but I seriously thought I would be blown away and I’m not.
When I got heads and cam done I was also not too impressed but it ended up really growing on me so I really hope this does too! I spent a LOT on this system and I’m almost thinking I should have just gotten the shocks, brakes and clutch done instead of adding in the supercharger. Again, hopefully once the clutch is broken in and I can romp on this car I will be more impressed.... and I probably will but first impression is not that great.
So, I realize it’s tuned for low elevation so that’s one of my issues for sure! I also think my tuner/builder made the wrong call on the 4” pulley because I wish he would have installed the standard 3.8” pulley so I would be seeing more boost and especially up here in elevation (apparently A&A recommends the 3.6” pulley for Colorado elevations). This is definitely holding me back but I do plan to bring the car back to the midwest long term so I’m probably going to plan to get the 3.8” pulley at some point!
My other issue is, and has always been the 317 cnc’d heads my previous builder installed (I wanted 243’s but they weren’t available in 2015 when I had the work done). These heads are low compression and have plagued me with a very soft low end ever since.... and I think these are also holding the supercharger back. I probably should have replaced the heads instead of doing the supercharger (my first plan) but so it goes.
Im also not super impressed with the current tune as it bucks way more then it used to. It’s manageable but I think I will probably have a different tuner tweak it and raise the rev limiter to 6500 or 6600rpms so I can ring a little more boost (I used to shift at 7000rpms and my dyno graph shows a very soft low end with all the power made at high rpms). If it’s not too much more I may have them swap the pulley to 3.8” at the same time. Might as well especially considering I’m underwhelmed with the setup right now. Yes it’s safe but I need more than this :-/
The one good thing is it turns out I have the V3 Ti head unit so with some changes I should be able to get to a more powerful place.......
Any suggestions or tips from those who’ve been down this road before? Thanks for allowing me to rant
You could pull the heads and have them milled to bump compression. That will drastically help the low and mid range. The centri blower is underqhelining when you roll into it. Slam it from 4500 and it's a different feeling completely. When I roll into mine at 3k I'm like holy **** this thing feels slow. But it's an animal from 4k up, that's why it's easier on parts.
If I pulled the heads I’d replace them with 243’s. It’s definitely an animal above 4K but it already was before. I’m thinking the 3.8” pulley and a retune with 6600rpm rev limiter and I’ll be much more impressed. And to be fair, I have to say the work done to my car was top notch! Bilstein shocks, brakes, new clutch, new shifter and all the supercharger stuff installed perfectly and no issues whatsoever! I think it’s just built very conservatively (I asked for it to be super safe) and a few tweaks and I’ll be happier! It sounds amazing!!! Lol
sorry it didn't fulfill all your hopes & dreams but with only 470tq on low boost, that's about the extent of it.
if you wanted drastically more low & mid-range that throws you back when you hit the gas, a PD blower like a Magnuson would've done the trick (more expensive & requires a new hood, too). they're torque monsters but require extra work to get them to breathe on the top end. centrifugal superchargers shine on the top end but typically drive marginally harder than stock below that... which is why they're easier on drivetrain components.
as for the 317s, since they're milled, it ain't as bad as stock castings, but upper 10.x CR helps improve the response & efficiency. 9.x CR is only better if you're running a lot of boost & plan to have the throttle buried all the time.
if you're planning to have it locally retuned, you may as well put the smaller pulley on it then. it shouldn't cost you any more then tuning it as it is now... if somebody's charging by the psi, i'd be looking for another shop.
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
pulley down and get a better tuner and that should change your mind... mine made about the same as yours n/a before the blower went on my car and I picked up 300whp/200wtq, it was a completely different car and the opposite of what you are describing
Thanks everyone..... when comparing my dyno graphs I see anywhere from 20-60 ft. lbs increase through most of the range so that's not bad..... I would have gotten that swapping heads also but I realize I have lots of room to grow here also. 4" pulley should have been the 3.8" and that can get swapped out pretty quick and to be honest I really want the power in the top end so I don't break stuff by having much torque it snaps axles or blows up the diff.
Also, my only boost experience so far has been rolling into it in 3rd and 4th gear pulls...... which wasn't that impressive before either now that I think about it. Ringing out 1st, 2nd and 3rd is what the real test will be once I feel the clutch is broken in enough. I have a feeling I'll probably change my mind after experiencing my first few 1, 2, 3 aggressive runs. I think I got a little worked up and was expecting some 9 second beast but now that I've thought about it a little more I haven't really given it a fair chance yet since I'm babying the clutch.
I'll report back once I really get to bang those gears and hopefully when I run the Colorado Mile in September I'll hit or get close to 180mph!!! My na best was 163.7 or something......
My clutch is breaking in and I’ve been able to play a little more but still a little underwhelmed and also a little nervous..... on a couple 1st gear pulls to 6200 I noticed my fuel pressure gauge flicker down to 50, just a flicker and back to 56-ish but that was enough for me to get very nervous. I talked to the tuner and Andy from A&A and this should not be happening so I have reason to be concerned!
i just got off the phone with a local tuner that is highly recommended and next month I’m going in to have him install a secondary fuel system and the 3.8” pulley and then tune it! I’m looking to get to 10psi, hopefully be able to raise rev limiter to 6500+rpms and I’m pretty sure I’ll dyno over 600rwhp. I don’t want more than 650-ish but I’m thinking I should get somewhere 600-650 and I’m happy staying there for now!
Thoughts? Ideas? Suggestions? Not interested in meth right now, I have access to race gas to make sure race days I am at least 93octane blended.
Its been a long road but I’m hoping this one more visit to the horsepower doctor is the TICKET
Just picked the car up after having the A&A single pump fuel system installed and a 3.8” pulley replacing the 4” I had on originally. My tuner added a 2 bar map SD tune and the results are way beyond what I was expecting..... made just over 9psi.
Now I’m happy, and hopefully I don’t have to spend any more on mods
10-29-2018, 04:38 PM
but with only 470tq on low boost, that's about the extent of it.
