A hot fuel tank is usually the result of an EFI engine where fuel is constantly circulated by the fuel pump and heated from the hot injectors. Do you run low-Z (low resiatance) injectors (peak and hold) or high resistance injectors (as most OEM)?
The low resistance have a very high amp flowing through them and get much hotter then the high resistance injectors.

I think insulating the tank from the radiator may not help much, but worth a try at least as its easy and cheap to do and fuel coolers are a lot more work after all.

I was told that the front of the tank is hot while the back is cool. I too believe the wrap will do the trick and it is in the KISS mode. .

Would never disagree with KISS solutions but would note that I get quite a lot of heat in my motorcycle gas tanks from circulating the fuel past a hot engine and back into the tank. BMW injectors and fuel lines are hanging right out in the airstream, so that might be a factor.

But you know what I most want to know is if that sucker is fun to drive. Brakes aside, of course, because it seems you've got that done. It just looks like you built a rocket, so does it feel that way in the driver's seat?

That is a good point. I do have 16mm phenolic spacers between the intake manifold and the heads which should keep a lot of heat out, but I agree some degree of heat will be coming from the circulation.

That said, the front of the fuel tank was very hot to the touch compared to the sides and back of the tank. I will wrap in an insulation material and determine if that helps with the temps.

-Britain

The car is a damn rocketship!!

If you watch the end of the AX video above, you can see where I come out of the 180deg turn and point the car towards the finish and hit the gas...the car accelerates like crazy!

Put it this way, the tuner at Cobb Tuning has driven everything from 600hp Subaru's to 1000hp GT-R's...he said he hasn't had this much fun in a car in 10 years.

-Britain

Brit,

I suspect that you will have a great time trying to sort out the brake balance, moot as JP says it is, but it looks as though there would not be a lot of work involved in swapping the front and rear lines on the master cylinders and giving it a try. Having gone to all the trouble you have, it would be a pity to spend half a season sorting it out.

Cheers,

I didn't mean to minimize the importance of getting it just right to fit ones driving style. Straight line brakers can go with more rear bias than one who likes a to trail brake. Some AXers like the back end to step out a bit under trail braking to help the car rotate. The last time I set the rear bias was so one could trail brake (if you had to ) without upsetting the car tho I pretty much was a straight line guy. It took 2 passes to get it close enough.

As an engineer sometime the solution to a particular problem can be way more complicated than it needs to be.

Case in point -
Problem: Need more HP
Solution: Take out the Porsche engine and replace with a Subaru engine.

Anyway, for the fuel temperature issue I have decided to try out McMark's idea with a simple insulated cover made out of the bubble wrapped foil stuff used on windshield screens in the hot summer. We shall see how it works this weekend.



Regarding the brake bias. All the calculations that have been completed indicate that this set-up should work how it is. I just need a few passes to get it dialed in and if that doesn't work then we can evaluate other options.

-Britain

Fantastic video, that looks like way too much fun. We need to get you to mount an iTouch/iphone on your dash and run an app like this so we can see/feel the G's

Doesn't Home Depot sell AC duct wrap? I use it on my test systems that have to go through temperature cycles. It's a foil based wrap with insulating foam with adhesion. Simple to apply. Just another thought.

-- brett

Yea, that would work as well. I like this solution because I can slip the insulation cover right off the top if I need to. We shall see how it works, I have my hopes up.

-Britain

The development never stops!
While the solution to more HP was indeed far from KISS, my intuition says that if you can avoid full thrashing of that engine (14 lb boost spike, Uh oh!) it will last a while and things will get (relatively more) simple.
Have you had a chance to see/feel/drive the newest Goodyear AX slicks?
I don't envy your situation with the big swings in temps and rough surfaces at home vs. the big SCCA venues!

The 14psi boost was not spike, that was sustained and just about normal for that engine. In fact, that is not even in the peak efficiency range for that turbo...the tuner wants to push around 18psi but I don't want to destroy the transmission and/or clutch. That said, I need to dial in around 7psi in cold or wet conditions and about 14psi in warm, sticky tire conditions.

I have not tried the newest Goodyear Slick. It is actually a DOT tire and not a slick.

-Britain

The good news is that most folks in the country have a similar problem.
Some guys are lucky with big open concrete venues but, I think, the majority are not. So we hammer away on our POS venues & hope for the best.

We went to Wendover last spring. Nowhere will prepare you for the grip that place generated. It ground tires to dust. The car done good.....when we got it running on all 6. I sucked as usual. My goal was not to finish DFL in class....OK, but I still sucked.

There's something to be said for racing in less perfect conditions. Here in So Cal some of our drivers have the problem of not enough rain practice throughout the year. Then they go to Nationals, get dumped on, and then get spanked. I doubt you guys have that problem. Plus the bumps really refine your car control.
Love the video, by the way. You know it's scary fast when it looks fast on YouTube! Keep up the good work.
Mark D.

Directly from Facebook:

Britain Smith
Great day at the SCCA Autocross at PIR. Took TTOD with the Where2Race sponsored Porsche 914. Finally got the boost under control, the brake bias in check, and had some fun driving the car in anger. Can't wait to mount new tires and take the car to Packwood in two weeks.

Isn't it cool to see another 914 race car project start to get sorted out and find success.

Keep up the great work Britain, we've all enjoyed watching your project and are enjoying seeing you compete, with success, at events.

Pretty soon everyone is going to want one of those WheretoRace T-shirt, i.e. the official sponsor of the sh##-bo# 914.

Do you have yellow t's?

Yes, thanks Randal. Great day at the AX, car stayed together well and is getting closer to what I considered sorted out. I actually cleared my head from thinking about the car and focused on driving...even JP noticed.

Here is a video of my fastest run. I am really going to have to look into getting a better camera.

http://www.youtube.com/watch?v=Y-Et-cJPgPM


https://www.youtube.com/watch?v=Y-Et-cJPgPM


-Britain

Indeed, on your 4th run when you came into my view I said to my self....ah, now he's workin' it.......then you looped it.....oops. Some fresh tiars well with help that but keep that trans alive.

Ok guys, it is late and I am going to bed...but before I do, here is a little to share.

Spent the day at COBB Tuning Surgeline finalizing the tune on my car. First off, what a great atmosphere down there and a very knowledgeable group of guys. Many thanks to head tuner Timothy Bailey and Brandon Lumpkins for their work, I know they enjoyed the ride around the parking lot.

We got the cold start enrichment ironed out so that the car is a bit easier to start on the E85 in cold to mild weather. We also tuned the new Turbosmart E-boost boost controller set-up maps at various boost set-points. This will allow me to dial in the boost level depending on weather, track conditions, course layout, and tire life. This set-up is trick and very easy to adjust.

Here are both the low boost and high boost dyno graphs.

Low Boost, 8psi:


High Boost, 14psi:


Now, the motor will easily take 18psi without issue. However, the clutch package is rated at about 400hp and the transmission/CV's are already close to the theoretical limit so I decided that I wanted to stick to this power level and avoid the exponential decay of transmission. Besides, the car is only 1800lbs and just about uncontrollable at the high boost levels.

Just as a side note, I have driven this car in competition for over 5 years and after driving it tonight thru the parking lot I got out and had a good adrenalin rush, complete with shaking hands, for a good 5mins.

Overall, the car is running great and the driving experience is beyond my expectations...it is going to be a fun year.

-Britain

If you were wondering, the 2-speed transmission works perfect for this application. There is not a hint of turbo lag anywhere in the powerband. Low gear is around 60mph and high gear is a measured 83mph at 7400rpm...the motor spins to 8200rpm and should be around 95mph.

-Britain

Wow, you were right, it's a rocket! And you're now officially having more fun than I am.

Holy crap Britain . I know the national level competition is tough but I do believe you now have a car that is able to take 1st . It's now just up to the driver

You can do it

A base model Gopro 170 work wonders even thought it's only a 5mpx non-hd camera with a 170 degree wide lense. Retail they go for $100. I got mine used on craigslist for $80 and spent another $30 on their suction cup mount. Here's a vid of my DD at a local small track:

Driver Side Fender mounted on my 02' IS300 manual 5spd

https://www.youtube.com/watch?v=0yHgz1GmqfU


Roof mounted on my friend's 02' S2000

https://www.youtube.com/watch?v=DlpmtWv1qKo

OK, we get it, you now have to wear a g-suit coming out of corners.

Can you believe those torque figures? And it comes on so early and stays so late.

I'd say that engine is just about ideal.

Thanks guys...like I mentioned in my post last night...the car gives you a shot of adrenalin that takes several minutes to wear off. I can't wait to drive the thing in anger!

dlo914, thanks for the info on the GoPro. I am looking to get a SmartyCam and while I know they are much more expensive, I would like to overlay the data from my AIM dash which will make the videos much more exciting to watch.

-Britain

Awesome

Just my be prepared idea but why not get a 18 psi boost tune? You know you will get aquainted really well with the tune you have and you WILL be able to use more at some point. The higher boost will mean lower rpms overall I would think although it might get a little twitchy. I always thought a new fast motorcycle was fast and it made my knees shake but only for a while.

The tune is good up to 18psi and there is no reason on the engine side not to go there. However, the last thing I want to do is burn up the clutch or blow the transmission on the dyno. Believe me, the car is a handful at 14psi and until I feel I need more power, that will be the limit. There is something to be said about going to an event and not have to wrench on the car or scramble to fix something.

-Britain

IMO Brit needs more rear tire to handle 14 PSI, much less 18 PSI.....having said that, I'm sure it will come.
The car is now nearly as quick as before the swap with Brit driving. It'll be quicker with new 10s but really needs new 12s. The 12s may well induce driveline breakage. Now is not the time for that. Now is the time for learning to deal with the beastie with 50 more hp/ftlbs and concentrating on the driving rather than worrying about the car. It appears to me that the driving style of the turbo vs the NA is different.

Yep espeically low displacement turbo motors like this one. You can see the cliff where power falls off from the dyno. Need to be on early and learn how to left foot brake like a mad man.

AWD cars are a little easier as they allow you to get on turbo early. 2wd is a little tougher but Brit will figure it out.

I liked the torque from my 2.3 DI turbo MS6. It pulled like a tractor from 2400 RPM. Of course I had 2000 more lbs of car to haul than Brit!

Sorry for the lack of updates guys, been really busy with work and spending time with the family. Got some time this last week to get some items in order.

At the last event up in Packwood, I dealt with fuel starvation and fuel temperature issues. Basically, about the 4th or 5th run in the car (with 2 drivers), I would get fuel starvation issues going thru sweepers and long corners. I would bring the car back into the Pits and top off the fuel tank. While the fuel level was not really low, I would fill it up anyway. After doing this, I observed fuel coming out of the vent tube on the tank. There is a check valve in the tank, however it was fluttering up and down and letting fuel thru. I determined that this was a result of high fuel temperature (E85) that was pressurizing the tank once the cap was installed. I was unable to continue running that afternoon and have made some changes to the fuel system that I will test this coming weekend.

In this older image, you can see the position of the fuel pump. I had it mounted about 3" higher than the bottom of the tank and farther forward...meaning the fuel had to go uphill and forward while the car was accelerating. I guess I was under the assumption that these pump had more suction that they really do.



In either case, I have now relocated the pump inside the passenger compartment and level with the bottom of the fuel tank. The fuel line now snakes by the steering rack and thru the front bulkhead.





This configuration will also have the added benefit of keeping the fuel pump cooler and it is not exposed to the heat coming off the radiator. Further tests and observations will be completed at the upcoming events.

I also tried my hand at some sheetmetal work to complete the radiator shroud between the front bumper and the radiator itself. It is really nice when you have access to a shear, brake, and one of those air powered nibblers. It is really hard to take a good picture of this, but it is all sealed up and you get the general idea.



And finally, got the car corner balanced and aligned. I was surprised to see some of my alignment specs out from where I expected them to be, but I got the car where I want them. The corner weights came out perfect and I have a solid 45/55% weight distribution.

-Britain

Despite the work I had done to the fuel system, I continued to have fuel starvation issues. I believe that the combination of fuel slosh and a high flow fuel pump combined to emptying out the sump in the fuel tank quicker than the fuel could return....therefore causing air to be sucked into the system. Therefore, I set about to redesign the fuel system with a much better set-up.

The first thing I did was mock up the approximate size of the JAX Pro Stock fuel tank (8x8x15") in cardboard to determine if I could get it to fit in the stock fuel tank location.



When I called JAZ to discuss the tank, I was able to order it in the exactly specifications that I needed. I went with a high flow AN-10 fitting at the bottom to feed the fuel pump, an AN-6 return line fitting, and an AN-8 vent line fitting.

This is the beginning of the new fuel tank install. I got the tank in "natural" finish so I can monitor the fuel level without having to look down inside.



Here is the tank completely installed. Worked perfectly all the way down to the level of the fuel in this picture. The engine felt so much more responsive and never bogged down...success!



Placing the tank in the stock location not only allowed an elevative position in relation to the fuel pump, it also allow me to fab up a new firewall to separate the radiator heat from the fuel system.



After running the car through 16 runs at the last AX event, the firewall was VERY hot to the touch and the fuel tank was only moderately warm. I am very happy with the results and now I can return my focus on driving.

-Britain

With all he radical changes you made to that car if it only took you that long to sort things out it means you've done an exceptional job. Congrats. Be proud, that's VERY well done and we're all envious.

Many Thanks.

It was actually quite frustrating that of all the changes made to the car, I was fighting the fuel tank. Car is ready to go for the WCR in Medford in two weeks. I also bought a new truck to tow my trailer more efficiently on long hauls...can't wait to make the trip.



-Britain

How did it go? Did you win?

Here is a video from the last event taken with a friend's Go-Pro. I need to pull the video from my camera to compare. I will be the first to admit that my driving is a little behind after spending all my time sorting the car, but now that the car is working well I can focus on having fun again.

The sound of the engine is awesome, gotta love the Suby spinning to 8200rpm. Enjoy...

http://www.youtube.com/watch?v=u8DUqVoMGMk...utu.be&hd=1

-Britain

Looks and sounds great

Awesome venue

Yea...venue sucks. The car is actually a bit to stiff now for that crappy place. I can't wait to stretch its legs down in Medford and then Packwood on the same weekend. Let the fun begin!

-Britain

Here is in-car video from the same run. Little different perspective...just as much!

http://www.youtube.com/watch?v=iNdMq03Zwg8...eature=youtu.be

-Britain

Looking forward to seeing you run down here

Well, it has been a while since I have updated this thread.

Two weekends ago was the Packwood National Tour, me and my co-driver took 1st and 2nd in a field of 14 drivers. While it was nice to finish out on top, we struggled in the car all weekend due to lack of rear grip and changing weather conditions.

Here are the video's of my fastest runs.

Saturday:
http://www.youtube.com/watch?v=L4yHNRq6cbI

Sunday:
http://www.youtube.com/watch?v=u0lQXPahUvw

With the new engine set-up, as more power is dialed in with the boost controller all the shortcoming in the suspension start being amplified. To date I have already corded two sets of rear tires and I have pretty much destroyed a third set after running the Tour and the ProSolo event this past weekend.

To dial out the understeer on the car, I went about stiffening up the rear suspension from 275lb to 325lb rear springs. With that change I had difficulty putting the power down and the rear of the car became very tail happy both on and off the throttle. Adjustments to the front sway-bar did very little to help.

During the ProSolo this past weekend I decided to revert back to the 275lb rear springs and that made a world of difference in getting the power down and settling the rear end. In fact, it was so dramatic that I red-lighted three runs in a row despite leaving the tree at the same time as I did on previous runs. I won't say that it cured the oversteer, but it helped.

Here is a video of the ProSolo fun:

http://www.youtube.com/watch?v=cp4KiVPQSr8

-Britain

Now it is preparation time for Nationals. Due to the struggles that I have had with the current tire set-up...I have seen the light and now realize that it is time to try something different and go big!

Therefore, with the 3 free tires that I won thru contingency with Hoosier, I am going to switch from Bias Ply to Radials. I should be able to get at least 2degs of negative camber dial in, hopefully a bit more. I have also decided to increase the mechanical grip in the rear from 10" to 12" wide tires. This will require me to do a little "modification" to the rear fenders...but as they say, Go Big or Go Home!

I should get the tires in the next week and I will post pictures when I receive them.

-Britain

So, this brings me to the topic of my next project. I want to ditch the '70 era suspension design and move into the 21st century.

Here is my problem.

Front Suspension: Current set-up is McPherson strut design which gives ~2.5" of scrub with 8" wide wheels. You are also limited in available, acceptable, shock designs.

Rear Suspension: Semi-Trailing arm which is making it difficult to get the power on the ground.

My plan is to move to a double wishbone, multi-link suspension set-up both front and rear. With that in mind, I have made some measurements and decided to basically transplant a Lotus Elise/Extige suspension onto my chassis. I will optimize the positioning of the attachment point for my ride height and basically copy the good hard work from Lotus for the rest of the placement. The best part is that the available shock choices are infinite...I have seen sets of Öhlins for around $1000 to $1500.

Here is a good view of both the front and rear set-ups.

Front:


Rear:


I am currently working on locating the necessary parts, so the ball is already rolling. I will post pictures as I go. If you know anyone that might have Lotus suspension parts, please let me know.

-Britain

Wow this is a fantastic build just read the whole thing tonight. I hope to be going down this road by next year sometime. I will definitely be hitting you up for those wiring diagrams. I just cant justify running an ej207 and not utilizing the avcs.

Not to throw another project on you but have you ever thought about doing an electric shift system. I realize its only two gears but it would allow you to keep your hands on the wheel.

Secondly, what is with that rear wing? A class restriction? it looks like its just a wall. If you want to know where to get a really nice carbon dual element wing with real engineering and CFD numbers behind it let me know.

Great build either way and looks like a blast. Im hoping to come out to nationals this year with our race car (Colorado state FSAE). We retrofitted an aero package and gained about 30 hp so hopefully we can be more competitive.

Yea, I would love to get more information on a rear wing from you. The spoiler is left over from the days that I ran E-mod.

I look forward to meeting you at Nationals.

-Britain

Britain,

Have you perhaps considered grafting in a suspension from a Boxster. This reasoning is based on a couple of factors: 1.) parts are plentiful and sure to be lower cost than the Lotus parts, 2.) lots of mature race development with spec Boxster racing; they are a very good handling car. I'm a roadrace guy, so I know nothing really about AutoX, but there should be enough similarities. Just a thought.

Andy1

photos!!
Great job so far, and good luck getting it sorted for the BIG SHOW

Heres the write up on the wing development. It's definitely tailored to road racing but it has real engineering behind it and is sure to work. Good read too, not too complex.

APR dual element wing

It will undoubtedly be a while before production but it might be ready for next season.

Hey Andy. The Boxster suspension was evaluated, however it is built for a heavier car and still uses strut design which is what I want to get away from. I think you would be surprised how cheap the Lotus parts cost.

-Britain

Very interesting article...we will be in touch. I have address the power, now I am working on suspension, and finally I will optimize aero.

-Britain