Well all I'm using of the stock bottom end is the crank. The engine is sitting on a stand stripped down to a bare block. And selling the Qjet wouldn't be a major source of financing but every dollar counts. And I'm not looking for earth moving power, just enough that I'd notice it and to be different from my friends.
pres589 wrote: Can I go and be the huge jerk in the room and say that if you are at the end of the budget scale to where selling a used Q-jet is going to provide noticeable funding assistance to this project, you may be smart to hold off on this project and just get the 307 running really well as a naturally aspirated engine? Here's my logic; the 307 has fairly trash heads from the factory. Are you still on factory heads? They have lower compression that deals with boost well but I don't know how strong the pistons and rods are... How much do you have to spend on all of this, do you know exactly what the turbo is / has the turbo been purchased or are you still working on that as well, etc etc? The more I think about a stock 307 bottom end (especially one that's had real mileage on it) dealing with ~350hp, I'm not sure how mechanically sound this plan is.
good point, and it will make it easier once you get the 307 running good to diagnose any issues after installing the turbo since you'll know its not an engine problem.
and i cant speak for bottom end strength and head flow of a 307, dont know much about them
pres589 wrote: Can I go and be the huge jerk in the room and say that if you are at the end of the budget scale to where selling a used Q-jet is going to provide noticeable funding assistance to this project, you may be smart to hold off on this project and just get the 307 running really well as a naturally aspirated engine? Here's my logic; the 307 has fairly trash heads from the factory. Are you still on factory heads? They have lower compression that deals with boost well but I don't know how strong the pistons and rods are... How much do you have to spend on all of this, do you know exactly what the turbo is / has the turbo been purchased or are you still working on that as well, etc etc? The more I think about a stock 307 bottom end (especially one that's had real mileage on it) dealing with ~350hp, I'm not sure how mechanically sound this plan is.
It's a fair point. Selling the Qjet could definitely help a $2014 Challenge effort, as we know, so let's stick with that type of budget constraints. have there been any carb, turbo cars at the challenge? I am not sure. Perhaps a Andy nelson esque small block would be more appropriate (to the OP, Andy brings small blocks to the drag strip for the Challenge (entire car for less than the number of dollars per year AD, so $2014) and runs deep into the tens with cast-off race heads and custom headers he makes himself along with copious ingenuity and lightness) than a turbo.
So, to recap, a NA build, even on the 307, may be a good choice. If you're dead set on the turbo, we can probably get you there, but the recipe isn't really scienced out.
I'd like to have a turbo. And it actually doesn't sound like a bad idea to get the engine together NA and go from there. Another question, I've seen people mention this Challenge on here but I have no idea what it is. Care to explain?
Well, it looks like you can pick up a complete tuned port injection manifold setup and an assembled MegaSquirt 2 ECU on ebay for about $350. If you hit Craigslist and/or the local salvage yard you could probably drop the price of the intake a bit.
A holley DP looks like its about $350? and you still need a carb hat, $80 and the parts to mod the carb.
QJets go for a couple hundred?
To me, the tuned port setup would be easier to tune (nearly any old laptop can be used and you can tune from your seat). If not requiring more work up front. It allows more finite fuel control, so less chance of blowing up the motor due to a lack of fuel. Carbs with turbos tend to have to run very rich to survive and that means you're leaving power on the table.
Here's an example of how to convert to EFI with MegaSquirt from a carb:
http://www.diyautotune.com/tech_articles/megasquirt-carb-to-efi-part1-nova.htm
DCharger68 wrote: I'd like to have a turbo. And it actually doesn't sound like a bad idea to get the engine together NA and go from there. Another question, I've seen people mention this Challenge on here but I have no idea what it is. Care to explain?
http://grassrootsmotorsports.com/events/2014-challenge/
If you want to go stupid fast for stupid cheap, it's an excellent template.
In reply to DCharger68:
The Challenge is held in Gainesville, Florida. Here's a link to the details on the challenge:
http://grassrootsmotorsports.com/events/2014-challenge/
Even if you don't have a car ready, join up with another team and lend a hand, or just come down and watch the insanity and chat with folks.
Also, do a Google search for Andy Nelson and GRM Challenge. Lots of info available on building 180 degree headers, cylinder head selection, scrounging the best parts from the local swap meets, etc.
The more I look at it the more I like the idea of using turboswede's idea. I'm not in a big hurry right now and I may save up a few extra bucks to do that.
In reply to DCharger68:
When you go to buy the MegaSquirt ECU, head over to DIYAutoTune after reading the article I linked and buy the parts from them. MadScientistMatt works there and can lend a hand with any questions you might have. Many of the rest of us can lend a hand as well. GRM has done a couple of articles on MegaSquirt installations and you can order the back issues.
If I had a little more cash and lived a little closer I'd probably try to compete this year. Maybe I'll get to in a couple years
In reply to turboswede: Alright. I'll probably have more up on it this summer. I've gotta do a bit of body work on my car and get the bottom end of the engine built. Plus headwork etc. But the TBI would bolt to a weiand action+ dual plane wouldn't it?
In reply to DCharger68:
Okay. For a moment I had a vision in my head of this going on in situ in the engine bay of a '71 Nova. Which is a cool vision but not quite what I'd hope for.
Here's what I think. I think tuning this thing is going to be easier to accomplish using port fuel injection. I think finding a TPI setup at a swap meet or under the bench or whatever you have at your disposal would be easier to tune vs. a carb. A Megasquirt and TPI would be the direction I'd take this. That's my 2 cents from a guy that's never built one so grain of salt.
The numbers on the block told me the engine is from a 68 nova, if that helps your vision. But its going in my 77 camaro. And I'll see what I can find between the tpi and TBI.
Wait. TBI - Throttle Body? I guess that would be easier to tune than a carb although you would probably run out of stock injector pretty easily. TPI - Tuned Port Injection, so port injection, the style with the big box plenum hanging over the lifter valley, suspended by tubes from the plenum down to the ports. If you're going to go EFI, I can't think of a reason not to go with TPI.
I guess I could jack it off my buddy's IROC lol. But there's a petty good size swap meet I go to in southern MO. Im sure someone there will have something I can use
yea for efi TPI is the way to go on a budget, although the stock TPI manifold is a reasonable bottleneck but can be overcome with more boost, or maybe try and find a used aftermarket TPI if you can get it for the right price but if not the stock one will work well enough
I wonder would it be possible to port the tpi any
Probably not much. The runners are a bit of a restriction, but honestly you're running a smaller motor, so it isn't as big an issue as some would say.
The heads are also not that great, but then again, many problems of this type can be fixed with the masterful application of boost.
Also, it has to be said, too many changes at once can lead you to run in circles trying to sort it all out and get them working together properly. Keep it simple, get it freshened up, convert it to EFI and once it is running well and you've got the parts gathered to add a turbo or two, you go for it!
Lots of recipes available online and especially in print on how to put together a small-block to do what you want. So a good idea might be to start gathering parts for a bigger/better engine once the current one is running.
I like that plan. It seems like an ideal way to do things. Thanks for the help. Apparently you can port TBI out to 600cfm. I wonder if its possible to get bigger injectors for it.
I don't think the injectors used were anything special, so larger flow rate units should be easy to find. SLP sold better runners, which I believe are actually worth doing if you want to rev this motor much, and there were bigger throttle body units and air foils for said throttle bodies. Honestly though, I'd agree with the KISS-style plan of action and just get the thing running right as stock, then start throwing little improvements at it as budget permits. And it'd give more time for shopping around for good deals on parts.
Im gonna build NA and go from there. But Id like to start with something that I don't have to change completely later. What's KISS?
Old acronym, "Keep it Simple, Sxxx" where X is "Stupid" or "Silly", etc.
Learn something new every day I guess
Hmm, I like where this project is going. The TPI stuff is plentiful and cheap and used MegaSquirts show up on the classifieds here from time to time. A 5-liter with a modest turbo would definitely be build-thread-worthy. Welcome to GRM.
What I described is essentially the scientific method.
http://www.circletrack.com/techarticles/ctrp_0707_motorsports_science/
AKA:
Observe Define Hypothesis Experiment Conclusion
Many times what happens is that people change a bunch of things at once, have a problem, but since so many things have been touched and changed, there's no easy way to sort out where the issue may be.
So start simple, get it running (maybe even on a stock ECU by stealing the entire working EFI setup from a junkyard rig), then start adding changes/improvements that are desired and if something doesn't work quite right, back that change out and see if it improves or changes.
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