Why did my 1/4 ET go up after mods?

Bolt On John · May 10, 2004

Hi guys, it's been a while since I posted here (long story) and the same long while since I've taken my stang to the track. Well over a year ago, my last time at the track, my stang got a 13.8 @ 97.4 in the 1/4 without the intake, TB, and Nos kit listed in my mods below, (ie: with the stock intake/TB). On that trip to the track, my car was runnin consistently in the 13.8 - 14.0 range with mph's between 96-98. 2 years and $1000 in mods later, the best I pulled at the track this last saturday was a 14.1 at 95 mph. At first it was runnin in the mid 14's, but that was with some horrible reaction times and 60 ft's that I chalked up to my rustiness as a driver, but after my 10 runs in the day I felt like I had gotten back in the groove, with .5 - .7 second RT's and 1.9 60ft's, yet I could not get any better than 14.1. I know the intake and TB alone shouldn't give me more than 20 hp extra if I'm lucky, but why does it seem slower now? It doesn't actually feel slower than before, and even if it was my driving alone I should still have a slightly improved mph shouldn't I? What are some of the things I should look at to improve this (other than my driving)? Nothing else has really changed since the previous trip until now except for the parts. It hasn't gained a whole lot of miles or had any real problems in the past two years, and it was running at the same weight, tire pressure, timing, TPS setting, etc, as before. Would a standard tune-up help (plugs/wires/etc)? Should I be shifting higher/lower with my new intake? (I was launching at 5500, shifting at 6) Any ideas?

blk9450 · May 10, 2004

that intake is meant for a built motor that can rev high, with that intake and the bigger tb, i think you lose velocity in your intake, plus some torque from the shorter runners.

IndyBlk5.0 · May 10, 2004

intake..... your motor would like a cobra style, but not that style of intake with stock longblock thats for sure...

Bolt On John · May 10, 2004

Ok, well that intake was chosen because of the nos kit and because that's what I want on my future motor, but while it's on this block what are some thing I can upgrade to help give me back some torque and hp? Will a bigger MAF and injectors help?

IndyBlk5.0 · May 10, 2004

bigger isnt always better. The only way you will see more power is with heads that can flow enough air to satisfy the intake and make it "happy"... the tbody is also too large for your setup.

blk9450 · May 10, 2004

you should sell the rpm and get a cobra or tfs

Bolt On John · May 10, 2004

Well I don't think I'm going to sell the intake. That would make my nos plate worthless and it would be a lotta trouble to goto over 3 tenths. Would switching back to my stock TB help with this same intake?

2NDTIME · May 10, 2004

6k is way too high to be shifting with stock heads and cam. I would try closer to 5200. I switched from 6 to 5-5.2 and picked up 5mph

Bolt On John · May 10, 2004

Hmm.. I will definately try that next time. I was definately shifting higher than I used to thinking this intake would make more power at high rpms, but it looks like I was wrong.

HO93LX302 · May 10, 2004

2NDTIME said:
6k is way too high to be shifting with stock heads and cam. I would try closer to 5200. I switched from 6 to 5-5.2 and picked up 5mph

that all depends though.. if you don't have a power adder.. i was shifting at 6k with my stock long block but i had a blower which made 10psi @6,000

90mustangGT · May 10, 2004

You have some good mods but on the stock heads, they just can't put out thier potential. Maby you should get the Performer regular upper with longer runners, which bolts right on the lower you have. I am sure you could find someone to trade with you, maby with a little cash also, so you can come out ahead.

Or maby you just need some heads. You have everything else. That would wake up your combo. I mean like a bucket of ice water wake up call!!!

MustangMulch · May 10, 2004

I'm sure the 6k RPM shifting has somthin to do with it. Go back to the track and try shifting around 5000-5400 and see what happens. A good tune up can never hurt either.

millhouse · May 10, 2004

I have to shift at 5700 rpms with my performer intake. I imagine with that rpm, 6000k is about right. The problem is though, because you shifted your power higher up in the rev's, you may be experiencing some valve float due to it, which can definatly hurt your power.

Like it was mentioned before, you'd be better off buying a performer upper and keeping the rpm for later engine mods.

Also, did you re-check your timing after the intake install? When I removed mine, I marked everthing and called it good. After a dissapointing trip to the track, I found out that it was now set at 8' timing. If you havent checked it, you'll want to do that.

Bolt On John · May 10, 2004

Maybe I will look into a trade for a regular Performer upper. What heads would you recommend for this setup or should I just port the stockers? How much would I normally pay for porting them?

nitroponynj · May 10, 2004

the rpm isnt to big you were shifting to high, look at your MPH its way low unless your clutch is spent you were shifting way to high,,,coming off the line at 5500 with anything other than slicks is gonna be tricky to launch without wheel spin here was my setup before heads cam intake

1991 GT longblock, professional product RPM replica intake with yes a 75mm t/b stock injectors mass air meter, cold air induction and 41o gears and a motor with 185,000 with the stock clutch it went 13.4 at 99.?? with 26x10 slicks with a 1.74 60ft so your headed towards the low 13s check your timing set it to 16-20 advanced remove the sway bar and drive it like youstole it ,,,shift the car no higher than 5500 and youll be writing us back next week saying damn i went 13.6s lol pm me when you go back to the track again,,,ooooohhh get a few bqags of ice and a garbage back throw the ice in the bag and put it ontop the intkae between rounds the garbage bag will keep the water from getting al over the place good luck.......

3" exhasut with flowtech 1 5/8 longtubes with warlock mufflers all through full exhaust with 410 gears it was fun but after 5000 it lost its steam ...my new top end seems to scream past 6000 with no effort at all and its now spinning the 28x10 sportsman pros with ease im putting the clicks back on it come track time

90mustangGT · May 10, 2004

Bolt On John said:
Maybe I will look into a trade for a regular Performer upper. What heads would you recommend for this setup or should I just port the stockers? How much would I normally pay for porting them?

I have Thumper heads which are ported E7's and I got the double valve springs, which are real nice, no valve float to the rev limiter. Paid about $700 total. The heads made a huge difference.
www.thumperoforangepark.com

Some aftermarket aluminums are better but much more expensive. When all is said and done your going to pay around $1500 for some really nice ones, but you can pick up some decent Edelbrocks and base model TFS's for a little over a grand. Valve train upgrades are recomended. You can also get some GT40 series heads out of a junk yard pretty cheap. Once again your going to need a spring upgrade for those also. Well maby not really "need" but you'll be glad you did in higher rpms or if your running any decent cam.

You can get some good results just by doing a home job grinding off the EGR bumps on the exaust side and doing a cleanup elsewhere. There is more to porting than just using a grinding tool and making the ports larger.

88stangmangt · May 10, 2004

talk to THUMPER he can port them his heads put people into the 12's and with nitrous and that intake with his heads i can see you in the high 11's.

Bolt On John · May 10, 2004

Thanks for all the help ppl. I forgot how great the community was here I am gonna hit the track again in 2 weeks, and I will try playing around with my shift points a lot, namely shifting and launching lower, as well as seeing if I can turn the timing up any higher and I might even try the old short-belt trick again. I want to see a 13.5 @ 100 mph out of this current setup (even if it takes a few track-only tricks like the short belt). After that I will probably be interested in talking to thumper about portin my heads. It would be awesome to see 12's out of my stang w/o the nos. I was able to install my nos kit and intake upper&lower myself without any huge problems (there was a nasty vacuum leak but I eventually fixed it), but I'm kinda afraid to mess around with removing and installing the heads. Does this take any special tools or super-precision or can anyone with mild mechancial skills do it?

maverick0716 · May 10, 2004

Bolt On John said:
...first it was runnin in the mid 14's, but that was with some horrible reaction times and 60 ft's that I chalked up to my rustiness as a driver, but after my 10 runs in the day I felt like I had gotten back in the groove, with .5 - .7 second RT's and 1.9 60ft's,

Reaction time has nothing to do with your final ET. You could sit there for as long as you want and still get the same time. Time starts when YOUR car breaks the beam for YOUR lane. Just making that clear.

Bolt On John · May 10, 2004

maverick0716 said:
Reaction time has nothing to do with your final ET. You could sit there for as long as you want and still get the same time. Time starts when YOUR car breaks the beam for YOUR lane. Just making that clear.

Oh yeah, I forgot about that, but when I mentioned it I was mainly referring to it as a measure of how well I was doing with my driving. For me, at least, a bad R/T and a bad ET go hand in hand.

Why did my 1/4 ET go up after mods?

Bolt On John

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