93 Octane Pump Fuel Recipe Wanted

[greg davis]

I was disappointed to read in the GSXTRA (Nov/Dec 2003) that 12.50@107 with #16psi is the best to expect on 93-octane pump fuel.

Now I know that some of you will post you have gone faster than that on pump fuel and I do not regard Richard Lassiter as an expert by any means.

I am interested in building a combo that will work with pump fuel and provide good street performance to ward off any new ZO6 Vette that may like to play and with only 1or 2 trips at the strip a year where I may want to turn up the boost and go with race fuel.

I would think that I want to make boost as efficiently as possible and keep the intake charge temperature as cool as possible to run as much boost as possible with the given octane.

I am starting with a ’87 T-Type 72,000 miles, Posi, with only the current mods being a XP+ pump, Volt Booster, “237” regulator, KN filter with Kirban half lid, valve cover vents, throttle body coolant bypassed, Reds 93 chip (older model), OTC 4000E. It ran the 1/8mi at the BCA Nat’s at Bunker Hill, IN Dragstrip 9.27@76.88. These numbers do not mean much to me since they are not quarter mile times.

So after this springs currently planned mods of a TA49, 3” THDP, 2-1/2” exhaust, Hot wired pump, Adj. fuel regulator, Heated O2, 2400 stahl lock-up converter, Boxed upper and lower control arms, 275/50-15 BFG DR, New valve springs, New turbo oil line, New waste gate Y hose, RJC power plate? (haven’t made up my mind), Injectors (size to be determined) where does one turn next?

It would seem if my theory of making efficient cool boost has merit then does an intercooler upgrade make sense at this performance level. Would aluminum cylinder heads provide enough combustion cooling to allow more boost or does just the better airflow allow this? If better airflow obtains more allowable boost then are ported iron heads an advantage? I understand more air in more air out theory but was asking from a boost standpoint for the steel heads and I realize the cost of either of these items.

Or is mid twelve’s the limit of 93 pump octane?

I do not have a make or break set goal of E.T.’s but as low into the twelve’s or very high elevens would be nice in an everyday state of boost and tune.

I realize most posted signature times from people are with lots of octane and boost, if anyone would share the times with 93 octane vs. their race fuel times of their combo it would help me get a feel of where to proceed with my next mods.

So I guess really my question is what should my next bolt ons be for building a pump fuel recipe.

I also have not made up my mind on 3” cat vs. straight pipe. No emissions testing is required yet but if the negative performance difference is minimal (.2 E.T.) at this level I will use the cat and be limited to unleaded fuel only. Does the cat increase backpressure enough to cause a result on limiting boost?

An alky system is not out of the question but I am unfamiliar with all the systems in detail. I just checked out the SMC from a link here and at $349 seem like a good next step bang for the buck. Except when things go wrong in a system like that bad things are soon to follow. Are the alky systems causing problems with the cat or O2 sensor?

The car is not a daily driver and is running great at present.

I am not trying to beat a dead horse with this type of thread and I have read as many of the past threads as I could find but I am interested in my specifics and would like this to be a start to open a dialogue with some of you.

Thanks to all interested in helping.

 

[ULYCYC]

Do a search this topic has be discussed many times. The basic rule is you need a High 10's combo in full race trim to run high 11's with pure pump gas in full street trim. I run 11.90@ 119 with 17lbs of boost and pure 94 pump gas on drag radials.
This is how I drive my car daily. Good luck in your goal

 

[BLACK6PACK]

Do the SMC kit, best bang-for-your-buck mod you can do for a street car. With a bad tune and 95 degree weather, I can drive to the track, pull up to the starting line and bust off a 12.0 @115 mph without any tinkering. The alky is pretty easy to tune also!

 

[strikeeagle]

So many numbers get thrown around on this board.

My GN has a 52, a V-2, and on and on, and I seriously doubt it would do 12.5 in street trim...

Think about 12.5. 12.5 is a full second faster than, say, an LS-1 Camaro - nothing to sneeze at...

Judging by your 1/8 mile times it will be very easy for you to improve dramatically. But, low 12's/hi 11's in street trim? All I can say is - good luck, my friend.

 

[greg davis]

BLACK6PACK…the more I read about the SMC Alky kit I might forget all the mods and do it only. Just kidding the mods and alky seem to be the ticket.

Strikeeagle…. I agree about a lot of lofty numbers being thrown around , I went thru the same thing with my big block car, I can not tune it to touch the #’s the big boys turn and I will never run those numbers with the same combo. A lot of those good #’s are developed in the 60’ times I believe.

 

[JDSfastGN]

I am positive you can get more mph out of a TB on 93 octane. If you run 117 on race gas, i don't see any reason why you could not run 110-112 on pump gas. Thats a difference of 50-70 hp and that is about what you see on the difference between race gas and a better race chip verses a good street set up(I do know that aerodynamics plays a role as well). If you have a good set of flowing heads and a decent cam to match I think the goal becomes that much more atainable. Its not as impossible as a lot of guys say, it just takes a really good tune with Alcky/propain, or a good set of heads and the matching components to use them to the best of there abilities.

 

[NEARING]

I don't see why you couldn't run those times you set as your goal.
My best time is on 93, the 1st pass on the car at VMP last spring closed dump pipe and 5 psi launch.

It wasn't on a radial tire but a street slick and it was cold out side,
about 40 or maybe a little less.
I think you will need some head work and a converter.
Just my 2 cents, I am by no means an expert on TR's.

 

[TType85]

So far my best on pump gas (crappy 91 octane) was 12.30@115 at 14ish psi. That was with a 2.2x 60' no traction at all....

It did take a big turbo, mild cam, stock ic, stock heads and some other stuff.

I'm sure if I got the 60' down it would be an 11sec street trim car.

I'm going to a smaller turbo (63e) a FM IC and Propain. I expect to have it running 11's on 91 octane and propain

 

[UNGN]

Since boost is the "resistance to flow", lowering resistance will lower the boost for a given airflow.

Ported heads, larger intercoolers, larger turbine wheels, better flowing exhaust all reduce the resistance to flow and all can result in more power at a lower boost level.

Ported heads will give you the most low boost bang for the buck and will alow you to go faster than 12.5@107 on true 93 octane pump gas.

One trick I used to use was add a 1-2 gallons of 116 octane to a tank of 93. This will usually allow 18-19 psi and a little more timing than a regular 93 chip. This adds about $10 to a tank of gas, but will net low 12's even with stock heads and a small turbo.

If you add up the extra cost it's only about $300-$400 a year, which will buy you 1 ported head or 2/3's of a new intercooler, while safely removing about .75 - 1 second from your ET.

 

[ijames]

Like others have said, this has been covered many times and the short answer is to run 11's on 93 octane build a car that will run 10's on race gas. You are right that charge cooling is everything when you are octane limited so I think you want a bigger turbo than the 49 and a front mount. My best on a 60 deg day on QuickTime Pros is 12.15 at 111.00 and a 1.80 60', on 93 octane Exxon gas, bone stock long block, V2, PTE54, Yank 10" billet 3200 stall converter, good single fuel pump, and 72 injectors. You need bigger injectors when you are octane limited but my 72's are way overkill - I wanted them to have to develop chips for a friend who does need them. MSD50's are nice but don't go smaller and if you can, go bigger, to 65's if you find a chipmaker you like who does them well, or the 72's. At least a V4 stock location but preferably a front mount (CAS, Precision, or Cottons, whatever you can get a good price/delivery/deal on). Going from a stock big-neck intercooler to a frontmount is worth about .5-.7 seconds and 5-7 mph on a car already running 11's to 13's. Good ported iron heads are about the same jump but are much more labor to install. Unported GN1's are worth up to 1 sec over stock iron heads. The pump you have is okay, hotwire it, you need a K&N cone filter and cold air intake setup instead of the stock style you have now, the THDP and 2.5" exhaust are good choices, get the adj. fuel pressure reg, get some msd50 injectors at least and a 93 octane chip, and with a frontmount and ta49 I'd expect you should get 12.50's on 93 octane. I ran 12.60-12.80 with basically that (TE34, a hair smaller than a 49, the V2, and redstripe injectors that weren't enough). Going up in injector got me into the 12.50's and going up to the PTE54 got me to the 12.teens but that was with a modified stock converter that stalled at about 2800 rpms which wasn't enough to spool the 54. I wouldn't bother with the 2400 stall you have listed. Get a 9/11 from PTS for not much more money and lots more performance, and that will let you spool a turbo like a 60, 61, 54, or 62, which will get you into the low 12's on 93 octane on a 70 deg evening. You'll lose .2-.4 sec on a 90 deg summer day. To get into the 11's add the good heads and maybe an even bigger turbo like a TE45A or TE63 or a BB66 if you can afford it. Either the turbo or heads will get you 11's on a cool evening and both will get you 11's on a hot day and push 11.50's on a good evening. Oh, a good alcohol injection setup will basically equal one of the big steps I've listed, so a TA49, frontmount, stock heads and alcohol should run a high 11.

 

[NEARING]

How do you like that Yank converter?
Is it a lock up or non lock up?
Thanks.

 

[V6POWER]

I have run 11.96/117 mph with my combo on drag radials and a 1.8xx 60'. This is with 93 octane + SMC alcohol (denatured/distilled water).

 

[ijames]

Originally posted by NEARING
How do you like that Yank converter?
Is it a lock up or non lock up?
Thanks.

It's a 10" billet with lockup, but I've only locked it at wot a couple of times. They said it would take it, though. It does not have the posilock. It's turned my 54 from a lazy "get spooled up at the 60' lights at the top of first gear" into a tire frying monster with full spoolup in a couple of feet and the poor Nittos just get smoked now. I guess it's okay .

 

[REDS HOT AIR]

Originally posted by NEARING
I don't see why you couldn't run those times you set as your goal.
My best time is on 93, the 1st pass on the car at VMP last spring closed dump pipe and 5 psi launch.

I plan to do some street trim passes at begining of the season ..hopefully we can meet up and show some race cars up on pump gas ..

I dont think I'll have a problem with mid 11's on pump gas ..

I got tired of getting told I cant run no more last year without a roll bar so this year I think I'll be doing more street trim passes till someone talks poop then it'll be race trim and $ on the line ..

 

[NEARING]

With that LT70 I think VMP will tell you to go home on pump gas!
Bobby is trying to put together a track day rental in the near future, wouldn't have to worry about getting thrown out.
I get back from the Gulf and everyone is running 10's now!
Guess I need to get my slug to run right!

 

[NEARING]

Originally posted by ijames
It's a 10" billet with lockup, but I've only locked it at wot a couple of times. They said it would take it, though. It does not have the posilock. It's turned my 54 from a lazy "get spooled up at the 60' lights at the top of first gear" into a tire frying monster with full spoolup in a couple of feet and the poor Nittos just get smoked now. I guess it's okay .

What converter did you have before?
Why did you not go with the posi lock up unit?
Do you feel they are too hard on the tranny?
I want to get a Yank also but am on the fence about the posi lock up option.
Thanks

 

[fuzzyGN]

I think the 12.50 is the limit ASSuming you still have the stock injectors. My best so far on the stock injectors is a 12.64 in Las Vegas. Only 16 psi boost and WAY lean in third. If that run would have 60'd the way it did the previous run it would have been about a 12.53 ish. Run was made on slicks. My combo is faily mild. Just have a 206 cam, THDP, Vigilante converter, on a rebuilt bottom end. The turbo, intercooler, inj are stock. I have a lot left with just an injector change. I think a 12.50 is possible with a well matched combo that is capable of running 11.70's or so in kill mode.

 

[REDS HOT AIR]

Originally posted by NEARING
Bobby is trying to put together a track day rental in the near future,

you'll have to let me know ....I could really use a track rental..I've been talking with a couple people about renting MIR at first of season but I guess VMP would work just not gonna hook as good as MIR

also one of my buddy's did get shut down at VMP on a rental in his pinto only went 11.0 but they said something about his 138 mph trap speed (4 cyl. stock chassis no cage )

back to regular scedualed pump gas talk.

 

[ijames]

Originally posted by NEARING
What converter did you have before?
Why did you not go with the posi lock up unit?
Do you feel they are too hard on the tranny?
I want to get a Yank also but am on the fence about the posi lock up option.
Thanks

Do a search in the trans forum for "ijames" to get the full story. I ordered a gn turbo thruster 3000 with posilock and it failed. After lots of development they made me this one, and decided to leave out the posilock because "I didn't need it because this 10" is so efficient at 6000 rpm". Wasn't my choice or decision, grrr, and I had several conversations with them about the fact that these motors don't see 6000 rpm, but they are still learning. That's the main reason I went Yank in the first place. I had a modified 2800 stall D5 before. The Yank is just as tight at 5000 rpm (same mph in the 1/4 and same rpm at 100 mph as the 2800 stall D5) but stalls about 3200 at 0 psi boost and flashes up from there at launch. The Yank has a lot of torque multiplication. I know Bruce's 9/11 is a great converter, also, but I can't give numbers to compare them except that his is a few hundred $$ cheaper and will definitely take wot lockups. I was really torn between the two and the posilock sold me on the yank, plus the desire to try something new and different in the tr world. In the past I've never locked up at WOT to save the wear on the converter and trans.

As for a 12.50 on stock injectors, I'd be shocked to see that done on 93 octane. I was way out of fuel with redstripes at 12.50 on 93 octane. Race gas, some timing, and lean it out some, sure, but not on 93.