What does it take to run 13 seconds?

[Tooky]

I am looking to hear detailed accounts of owners who have VERIFIABLY ran 13 seconds in the quarter mile at an actual dragstrip, with timeslips.  I have heard a lot of tales 3rd hand and I am sure a portion of them are true but I am looking for what main modifications were required to accomplish this.  I will be honest and say that I have some doubts as to whether or not the stock T25 could push this 3600+# pig into the 13s.

So if you ran 13s, what was your timeslip, what was the vehicle's weight, what boost did you run, what fuel, what tires, and finally what main modifications made you so much faster than a standard "Chip and air filter" TGP that is common here (like mine).  Thanks,

[Cookies]

I am too curious.. I at the moment just have custom air filter and top gun thanks to jeff. I dont know what my quarter is though.

[ShuGTXTurbo]

PM JeffM his car is running 13.5 in the quarter with the stock t-25 turbo.  He can probably give you a list as to what you can do to the car along with a list of parts that you can bolt on.  I plan on hitting 13's by the end of summer.  Here is just some of what I'm doing.

TopGun 160 chip
Custom Air Intake setup (Home Depot Special)
Phantom Grip LSD
FFP dogbones and underdrive pulley
A/C and power steering unit removal
Chill Factory fuel pressure regulator (www.chillfactory.us)
Chill Factory Mr. Freeze CO2 charged front mount intercooler
Stronger Drive Axles
MSD Ignition Coil Packs
Accel 8.8mm Plug wires
NGK Iradium Spark Plugs($9.50 a Piece)
3" Exhaust Straight through Hi-Flow Cat with no mufflers
:twisted:  :twisted:  :twisted:  :twisted:  :twisted:  :twisted:
If that doesn't put me down in the 13's I don't know what will.

[dbtk2]

When I get done with my STE it should be running consistant mid-high 13's on the stock turbo (I hope).

I will hopefully have all of these mods:

K&N Filter on Turbo
2.5" Exhaust w/no cat spliting into 2 straight through 2" mufflers
Removed A/C Fins
TopGun 160 Chip
160 Degree Thermostat
FFP Dogbones
FFP Underdrive Pulley
3100 Topend Swap (heads, intakes, throttle body)
1.6:1 Roller Rockers
Custom Headers
Custom Larger Crossover (to try to get exhaust pressure down)

If I don't hit 13's consistantly with that, I'll be pissed!!!

Shawn

[Tooky]

PM JeffM his car is running 13.5 in the quarter with the stock t-25 turbo.  He can probably give you a list as to what you can do to the car along with a list of parts that you can bolt on.

JeffM is a great guy and his dedication to the McLaren Turbo Grand Prix is unrivaled.  So with that said and with all due respect, your statement leaves a number of serious questions regarding the validity of your claim.

First off, the Garrett T-25 stock turbo appears to only be stretchable to about 250HP-275HP tops.  According to information on http://www.dune-buggy.com/turbo/turbo.htm, they say it's "good for 125-210bhp, maybe up to 250hp."  So how did he manage to get an extra 40% air flow out of the T25 over what is beleived to be the limit of this turbo?  I've never seen the answer to this question.  Let's allow for the possibility that the motor was enhanced internally to flow the extra air that the T25 compressor cannot (perhaps a stroked crankshaft, better flowing heads and camshaft); in such a situation how would this extra charge mass be exhausted when the stock crossover outlet and T25 turbine housing presents two of the largest bottlenecks in a STOCK power level?  This also has not been explained to us.

We also have no answers as to what fuel, what timing, what boost, or what other major modifications would make his car so much faster than any similar TGP (stock turbo equipped).  For years now, I've been hearing reports that he ran 13s. If Jeff wanted to share this information, I think he would have done it by now...  

So while he may have run 13s (verification/confirmation of those results remain to be seen), he hasn't let on to the "secret" and it certainly is NOT representative of what any board member might reproduce with THEIR TGP and the stock turbo, so it's a pretty worthless point of reference as far as I'm concerned.

Hopefully someone else can still provide a quantifiable report of their car running 13 seconds with a timeslip and the story on how it was accomplished, and especially the steps that any regular TGP owner might take to achieve the same results.

[Tooky]

When I get done with my STE it should be running consistant mid-high 13's on the stock turbo (I hope).

I will hopefully have all of these mods:

K&N Filter on Turbo
2.5" Exhaust w/no cat spliting into 2 straight through 2" mufflers
Removed A/C Fins
TopGun 160 Chip
160 Degree Thermostat
FFP Dogbones
FFP Underdrive Pulley
3100 Topend Swap (heads, intakes, throttle body)
1.6:1 Roller Rockers
Custom Headers
Custom Larger Crossover (to try to get exhaust pressure down)

If I don't hit 13's consistantly with that, I'll be pissed!!!

Shawn

To help achieve your goal, I would recommend that when you do the Custom Larger Crossover, you do it with a T3 flange and put on a larger turbo, for I beleive this mod will give you all the performance of the rest of your mods put together, for 1/3 their collective price.  The only problem is fabricating a downpipe but it should be a snap compared to fabricating custom headers.  On the other hand if you were someone to not do any custom fabricating, I'd recommend trying some of the largest T2 style bolt-on turbos you can find, they do exist if you look carefully... in sizes up to 450HP  :shock:

[maximage]

Shawn, I'd drop the headers out of your equation. Turbo cars tend to not like them as much, especially single turbo V-engines. The reason is the exhaust pulses. Unless you have equal length headres(which are impossible in our engine compartments), you would actually lose power over the stock manifolds. I would port the stockers, and go for more time on the x-over pipe.


Speaking of the crossover, why in the hello do these things need those stupid bellows joints? I see no reason wht they can't be solid pipe, anyone else have a better answer? I'm looking to do the same whne I build my spare engine for the turbo I have from my Supra project.

[90TGP]

When you rev the motor, it likes to rock back and forth. The bellows are flex joints which allow movement for the motor. No flex joints, cracked pipe from stress.

Back to the subject. Here's my list of mods. I'm hoping to break into the high 14s this year with good tires and traction. I ran a best of 15.09 while spinning all the way through first. I need better tires :oops:  

TopGun 180 chip.
Cross-X Pipe.
180 thermo.
FFP Underdrive pully.
FFP Upper motormounts with polyurethane bushings.
CarSound 2.5" in/out high-flow cat.
Dynomax 2.5" in/out bullet mufflers.
2.5" Cat-Back exhaust.
K&N filter on turbo.
Blitz Super Sound BOV.
DEI turbo insulation wrap.
DEI intake tube cover. It's placed around the upper intake pipe to keep the heat from the turbo out of the freshly cooled intake.
Removed a/c condensor.

Spring Plans:
Custom front mount intercooler.
Lighter 17" 17lbs/wheels.
Z-Rated tires.
Light weight race seats.

Hopefully I'll break into the mid-low 14s with the spring plans.

[turby]

My thoughts on the flex joints in the x-over. :roll:  Yes they are there to prevent stress cracks when the motor rocks. BUT the front and rear of the motor rock together. So, if the turbo bracket was built so it could flex, why couldn't the x-over be solid?

[Chris A]

The metal and fittment tolerances. Stainless expands at a higher rate than regular steel. The bellows allow for the turbo, and both manifolds to line up properly and seal. I've seen it that without the bellows the metal will crush and fail, and there can be leaks because of bad alignment. It has NOTHING TO DO WITH THE MOVEMENT OF THE MOTOR. The turbo, crossover, and downpipe move together as a unit. The downpipe is attached to the back of the engine and uses a donut gasket with spring stud retainers to connect to the exhaust. The movement is there for the engine rocking.

The original bellows failed mostly because they were of poor quality, and moisture buildup. Straight pipes would probably crack in a similar fashion. At the very least it would crumple.

Chris

[4PASNU]

It has NOTHING TO DO WITH THE MOVEMENT OF THE MOTOR.

Finally someone said it.  Thanks Chris.  I've been wanting to say something about this for a while now but didn't want to get into a pissing match with anyone.

[Jeff M]

It has NOTHING TO DO WITH THE MOVEMENT OF THE MOTOR.

Finally someone said it.  Thanks Chris.  I've been wanting to say something about this for a while now but didn't want to get into a pissing match with anyone.

Me too, especially since I can?t be everywhere all the time to help out, nor want to spend time arguing a learning curve :roll: .  From previous owners who have welded their crossover pipe solid, and in sending them to me as a restorable pipe/core for mine :evil: , I have found out first hand, and painfully as well when it comes to using these solid pipes, that the expansions and contractions destroy these solid pipes, and I mean destroys them from nearly collapsed pipe sections, horrible bends and deformed pipe sections, and huge gapping cracks, bad idea to go solid specially if you do not have some compensation for this. And a little info on what puts the pipes into extreme temperature cycles and expansion/contractions is the range of exhaust heat/or lack of heat going from WOT power runs to deceleration fuel cutoff/DFCO.  Obvious we understand the heat in the exhaust from running safely rich under boost, but then toss in the computer shutting the fuel off during DFCO when under heavy deceleration brings an exhaust that has no heat from combustion, damn cold as compared to regular exhaust temps cruising or during a power pull.  And before you get mad at the DFCO, think of its benefit in cooling down a hot piston and combustion chamber readying it for the next blast down the road :twisted: .  Very glad to hear maximage make this point of not just throwing some headers on the engine, managing the exhaust pulses is very important, very much so!!  That also includes the crossover pipe as well!!!  Crossover pipe you say??yes it is receiving exhaust pulses as well and if not built to coordinate/time properly those pulses, exhaust pulse from each side of the block will meet against each other at the Y joining part of the crossover pipe!  Looking at the design and pipes of the stock OEM crossover, the short end has nothing to complain about, smooth transition bend all the way through, the long end makes a nice gradual bend as well, with a very small single bulge on the short radius of the curve, no effect in disturbing the air flow!!  All in all a design that compromises little aside from poor workmanship and components that can be rectified!  Now if we had a bigger turbo that was showing some signs of turbo lag, some properly designed headers would be of value but how much  :?: without tests you won't know, but like anything, if you don?t got money to make your car run right (fix overheating, fix a tranny, fix whatever) then you should not be spending time and money on coming up with custom parts to go faster yet, make it run right before you make it run faster!

Bottom line, people need to first not get mad at the items on their car 8) , but keep an open  mind and just ask how good they are, and if there is better, but MORE importantly, just how much better something could be AND worth the time and effort and $$ to make or buy it.

Jeff M

[TGPilot]

When you rev the motor, it likes to rock back and forth. The bellows are flex joints which allow movement for the motor. No flex joints, cracked pipe from stress.

The cross-over pipe flange (where the turbo bolts to) is a fixed mount to a tranny bracket. As said by others they are not there for flex during the tilting of the motor. An analogy that might explain what the bellows are for goes something like this :wink:... Remember every Thanksgiving when people would fight over the wish-bone? Two people would put their thumbs on the top of the wish-bone where it comes together. Then you and the other person would put their fingers towards the bottom of the bone. You and the other person would pull until the bone snapped. Your thumbs don't move...but your fingers pry the bones apart until the bone breaks. One person would get the fat portion of the bone the other would get just the skinny portion.

Ok...picture the wish-bone which is now the cross-over. Your fingers are now the heads and exhaust manifold. Your thumb is the turbo mounting flange and tranny bracket.

If the wish-bone isn't dry it will flex and not break right? But if the bone is dry and rigid it will snap real clean. Well if you make the cross-over solid (rigid) it will work against itself with the extreme heat expansions and contractions and break or mangle itself... 8)

[dbtk2]

Shawn, I'd drop the headers out of your equation. Turbo cars tend to not like them as much, especially single turbo V-engines. The reason is the exhaust pulses. Unless you have equal length headres(which are impossible in our engine compartments), you would actually lose power over the stock manifolds. I would port the stockers, and go for more time on the x-over pipe.

I am getting headers only because I have to get custom manifolds for the 3100 heads anyways (different shaped exhuast ports).  Otherwise I would just leave the stock manifolds on there.  So I am hoping to have a guy make me some headers and a custom crossover (since the crossover is suposedly the biggest exhaust restriction we have)

To help achieve your goal, I would recommend that when you do the Custom Larger Crossover, you do it with a T3 flange and put on a larger turbo, for I beleive this mod will give you all the performance of the rest of your mods put together, for 1/3 their collective price. The only problem is fabricating a downpipe but it should be a snap compared to fabricating custom headers. On the other hand if you were someone to not do any custom fabricating, I'd recommend trying some of the largest T2 style bolt-on turbos you can find, they do exist if you look carefully... in sizes up to 450HP

I am planning on going to a larger turbo among many other things eventually, but I want to hit 13's on the stock turbo and what I listed above first, just to see if I can.  If not, then a larger turbo, as well as a few other things will be going on.  I haven't been able to find any big enough to support 450hp with the stock flanges though.  Are there any in the 300-350hp range with the stock flanges?  If so, let me know where I can find one, preferably fairly cheap, I would be very interested.

In my dads TGP I ran a 14.819 @ 92.72 with JUST a Topgun 160, 160 T-stat, and no cat, and it backed that up with a 14.842 @ 92.62, so it wasn't a fluke run or anything.  Everything else was stock, even the VERY restrictive stock air intake.  Not to mention that it needed a tune-up BAD at that point.  We put new plugs in it, and a K&N filter on the turbo, and there was VERY noticable difference, I would say 15-20hp.  It feels like a ~14.5 car now.  And my STE was significantly quicker stock than that one ever was, so I am hoping it will perform at least as well as that one did with the same mods.  So I find it hard to believe that with a little bit better launch, an underdrive pulley to reduce drag, a much better flowing intake and heads, and a larger crossover that I can't pull 13.9's consistantly.  Maybe you're right, maybe I can't, but I'm sure as hell gonna try.  I'm 16, I'm too stupid to know any better.

Shawn

[TGPilot]

Maybe you're right, maybe I can't, but I'm sure as hell gonna try.  I'm 16, I'm too stupid to know any better.

Shawn

Give 'em hell man!! 8)